1 
 
 
 Photography • 
 [5hs iSHsasasasHSTaisasHsasasaHsg 
 
 pj Dr. William H. Trueman s [jj 
 LIBRARY. I 
 
 
 FRANKLIN INSTITUTE LIBRARY 
 
 PHILADELPHIA, PA. 
 
 Class jL2L£L. Book(^i^.4?.2. Accession ...7-8 32.^ 
 
 Given by .-Z7r^:^..i^x^.,.../^.....Z^^.^.^^.^.^ 
 
THE '•LUND" LIBRARY OF PHOTOGRAPHY. 
 
 In Two Shilling Volumes, Net. 
 
 These books cover collectively a wide field, and include not only 
 text books on the numerous branches of both art and science, but also 
 volumes presenting photography in a popular aspect. Those dealing with 
 technical branches aim at plain wording and explicit teaching. 
 
 THE STEREOSCOPE AND STEREOSCOPIC 
 
 PHOTOGRAPHY. Translated from the French of 
 F. DROUIN by MATTHEW SURFACE. 180 pages. More 
 than ioo illustrations. 
 
 THE HALF-TONE PROCESS. By julius 
 
 VERFASSER. A Practical Manual of Photo-Engraving in 
 Half-Tone on Zinc and Copper. 126 pages and 59 illustrations, 
 with three engravings in half-tone by the Author. 
 
 PHOTOGRAPHIC LENSES : how to choose 
 
 AND HOW TO USE. By JOHN A. HODGES. An Elemen- 
 tary and Practical Guide to the selection and use of Photographic 
 Objectives. 148 pages and 36 original illustrations, including 
 eight half-tone engravings. 
 
 HALF-TONE, on the American basis. From the 
 
 Personal Experience of WILHELM CRONENBERG. Trans- 
 lated by WILLIAM GAMBLE. 164 pages, with 56 illustrations 
 in the text, and twelve supplement illustrations. 
 
 IN THE PRESS. 
 
 PHOTOGRAPHY FOR ARTISTS. By hector 
 
 MACLEAN. Over 150 pages, with 40 illustrations and diagrams. 
 
 IN PREPARATION. 
 
 SENSITIZED PAPERS : how made and used. 
 
 By Dr. H. C. STIEFEL. 
 
HALF-TONE 
 
 ON THE AMERICAN BASIS 
 
 FROM THE PERSONAL EXPERIENCE 
 OF 
 
 WILHELM CRONENBERG 
 
 (Proprietor and Conductor of the Practical Institute for Photography 
 and Mechanical Reproduction at Schloss Gronenbach, 
 Bavarian-Algan.) 
 
 With 56 Illustrations in the Text and Twelve Supplement 
 . IllustyajtiofiA, , 
 
 TRANSLATED BY 
 
 WILLIAM GAMBLE 
 (Editor of " Process Work " and " Process Year Book.") 
 
 Percy Lund & Co., Ltd., The Country Press, Bradford 
 and 
 
 Memorial Hall, Ludgate Circus, London. 
 1896. 
 
PERCY LUND AND CO., LTD. 
 PRINTERS AND PUBLISHERS 
 
 THfc: „c,c|u^^rv , pass's brad;f{)R(> 
 
 AND LONDON 
 
5 
 
 CONTENTS. 
 
 INTRODUCTION. 
 Photo-Engraving in America . . . . . . . . 13 
 
 CHAPTER I. 
 Apparatus for Negative Making . . . . . . 27 
 
 CHAPTER II. 
 The Negative . . . . . . . . . . . . 49 
 
 CHAPTER III. 
 Stripping and Reversing the Negative . . 80 
 
 CHAPTER IV. 
 The Printing Process .. .. .. .. ..87 
 
 CHAPTER V. 
 Etching .. .. .. .. .. .. .. 124 
 
 CHAPTER VI. 
 Finishing Work. Engraving . . . . . . . . 139 
 
 CHAPTER VII. 
 Vignettes .. .. .. .. .. .. .. 156 
 
 Conclusion . . . . . . . . . . . . . . 161 
 
7 
 
 PREFACE. 
 
 F all methods of reproduction none deserve 
 our attention in a higher degree than that 
 of Autotypy, or half-tone, not perhaps be- 
 cause its results are of so perfect a nature — in this 
 respect it stands far behind collotype and photo- 
 gravure, and hardly approaches lithography — but 
 rather in consequence of its speed in making a 
 plate, and from a plate printing an edition, and its 
 suitability in all respects for letterpress printing, 
 whilst on these two grounds it is also cheap. 
 Moreover, the productions of the half-tone process 
 are well suited for distribution among the people 
 as a cheap educational medium which will find 
 entrance to every household, and by presenting in 
 this way faithful copies of works of art will do more 
 to disseminate knowledge than lengthy descrip- 
 tions. We had long recognised the value of 
 pictorial representations, and had sought a more 
 decided method of mechanical reproduction for the 
 
8 
 
 HALF-TONE 
 
 deservedly high-developed printing press, until 
 Meisenbach solved the problem. 
 
 Look back to the earliest days of the process, 
 which commenced so modestly and insignificantly, 
 and consider the short space of time — not more 
 than twelve years — that the young process has 
 been developing, and realise the industry that has 
 sprung up from the idea of one man. As yet we 
 cannot see the end of these developments, for the 
 process of Autotypy has only just been adapted 
 to three-colour printing. A little space of time, 
 and where now only the form is presented, 
 sketched in grey monotone, we shall see the cheeks 
 redden, the eyes reflect their prismatic sheen, the 
 mouth display its purply lips, and Nature unfold 
 the whole of her colour charms. 
 
 I have endeavoured in the present little book 
 to leave out all matters of secondary importance, 
 and have only described with amplitude the kernel 
 of the process. As a practical man speaking to 
 practical men I have found theoretical considera- 
 tions of little value, but it seemed to me they could 
 not be overlooked when— as in the chapter on the 
 negative process— they were absolutely necessary 
 for the understanding of the work. I also thought 
 
ON THE AMERICAN BASIS. O, 
 
 it superfluous and only page-filling padding to 
 describe the elementary process of Autotypy, and 
 in this way dish up methods which have long since 
 been consigned ad acta, and only distract the atten- 
 tion of the reader from essential to secondary 
 things. Further, I have abstained from treating 
 photographic operations, as such. Who would 
 have the impertinence to attempt to write some- 
 thing new of a subject, on the practice of which 
 there is already so extensive and excellent a 
 theoretical literature ? I have made it my 
 principle in this little work to apply to no other 
 source than my own practical experience, a rule in 
 which I have been supported by noticing the often 
 incorrect formulae and directions given. On the 
 other hand, I thought it my duty to give to 
 Brother Jonathan the honour which he deserves 
 as the foster father of Autotypy, and to speak 
 as an authority of the arrangements and appli- 
 ances I have seen there. As to the supplements 
 to be found in this book, they are all produced in 
 my studio school, and for the most part are the 
 work of my students. This circumstance is to me 
 more precious, as it proves that the principles of 
 Autotypy which I teach to my students, and which 
 have also been laid down in this book, are the 
 
IO HALF-TONE 
 
 right ones, and that the efforts of those who hold 
 to them must be at last crowned with success. In 
 consequence of these favourable results I venture 
 to hope that the following pages will not have been 
 written in vain. 
 
 In conclusion, I must acknowledge the assist- 
 ance of my students, by whom the whole of the 
 illustrations in this work have been made, and to 
 their teacher in the etching process, Herr C. Fleck, 
 my best thanks are also given. 
 
ii 
 
 TRANSLATOR'S PREFACE. 
 
 HEN consulted by the publishers as to 
 the advisability of issuing a translation 
 of this work, I was pleased to testify to 
 its technical value. Herr Cronenberg has, more- 
 over, considerable reputation on the Continent as a 
 practical teacher of long experience in process 
 work, and this fact alone would be a guarantee of 
 its reliability. On account also of the fact that the 
 book covers ground upon which there is a consider- 
 able dearth of information it will be welcome. 
 The author does not pretend to be exhaustive in 
 the treatment of this subject, and the inexperienced 
 must not assume that the processes here described 
 cover the whole scope of American photo-engrav- 
 ing. I think, however, it will be recognised by 
 those who are familiar with American methods that 
 it gives a fairly complete resume of the principal 
 processes, and the details given are sufficient, at 
 least for those who have passed through the 
 
12 HALF-TONE 
 
 elementary stages of process engraving, or who 
 have practised the older processes, to enable the 
 work to be carried out with successful results. 
 There are some deductions and recommendations 
 of the author's with which personally I should not 
 agree, but I have not thought it advisable to 
 interlard the book with foot-notes and detract from 
 the work of the author, whose opinions as a careful 
 and successful worker are entitled to thoughtful 
 consideration. In the translation I have aimed 
 rather to present the author's meaning in words 
 intelligible to English readers than to adhere 
 strictly to the text. If there is anything 
 I have not made plain, I will endeavour to answer 
 any brief questions sent me through the publishers. 
 
 William Gamble. 
 
 London, January, 1896. 
 
i3 
 
 INTRODUCTION. 
 
 PHOTO-ENGRAVING IN AMERICA * 
 
 New York ! There it lies at my feet ! I stand 
 on the highest arch of the suspension bridge and 
 cast my eyes on the beautiful scene before me. 
 There flows past me the never-resting stream of 
 traffic between the two great cities, New York and 
 Brooklyn, thundering and tumultuous, but my 
 glance rests on the distance from whence no sound 
 penetrates, and where the glistening undulations 
 of the crystal atmosphere have laid the soft veil 
 of poesy on the blue waters of the port crowded 
 with ships, on their countless masts, and on the 
 far-extending sea of houses of America's greatest, 
 richest, and most interesting city. Nothing dis- 
 turbs the quiet charm of this striking picture. But 
 by degrees, as the colossal arch of the suspension 
 bridge plunges more and more into the heart of the 
 city, the gables of the houses grow, the noise and 
 
 * Reprinteil from the " South German Photographenzeitung " 
 
HALF-TONE 
 
 tumult increases, the storm grows in strength, and 
 the charm vanishes. Whilst on the top of the 
 suspension bridge we were far removed from the 
 every-day world, and gazed with an eye of idealism ; 
 here we now come to a picture typical of America 
 — a scene of exciting, restless, hurrying industry. 
 There is no place for Art, and no opportunity for 
 the principles of beauty. In this sense-confusing 
 wave of extremely competing industry, only one idea 
 prevails, calling forth all the sharp-senses, all the 
 spirit of perseverance, to profit by every advantage 
 offered, in the annihilating war of competition in 
 general, and in the battle of the individual, which 
 is here carried on. All that is original, new, 
 cheap, or beautiful, is thrown with uncomfortable 
 speed on the market. To-day one possesses it, 
 to-morrow it is the property of every one, and the 
 day after it is superseded by a new invention and 
 thrown into the lumber room. That this is not 
 accomplished without the trumpet of advertise- 
 ment is understood. Even the keen competition 
 is one important factor by which this young 
 country, in the course of a few decades, has 
 attained such an unexpected height. Naturally, if 
 this country demands constant innovation to im- 
 press the public, and secure a market for its 
 products, its industries must profit thereby, and as 
 the buildings in New York increase from storey to 
 storey in height, so increases within the capability 
 
ON THE AMERICAN BASIS. 
 
 15 
 
 of production in business. From day to day it is 
 sought to simplify the present working processes, 
 and to invent new mediums for accomplishing 
 more work in a shorter time. 
 
 Could the circumstances be otherwise with 
 the industry of reproduction ? Twelve years ago, 
 hardly more was known than the slow and expen- 
 sive method of wood engraving. The mechanical 
 reproduction by photography was still in its 
 infancy, and etching in metal was almost unknown. 
 The process of washed-out gelatine, and swelled 
 gelatine were next introduced. The results were 
 very beautiful, and these methods subsist even to 
 the present day. They proved a dangerous enemy 
 to the woodcut. It was soon found that instead 
 of engraving on wood it paid better in many cases 
 to draw upon a photograph in wood-cut style, and 
 then bleach the photo out, the resulting drawing 
 being converted by a mechanical process into a 
 printing plate. The wood engraver was changed 
 into a pen draughtsman, and in him originated an 
 entirely new industry, which now gives employ- 
 ment to thousands of busy hands. 
 
 The swelled and washed-out gelatine processes 
 were brought to a high state of perfection, enabling 
 them to be worked with certainty. At the same 
 time appeared the epoch-making innovation of 
 Autotypy (the half-tone process). The success of 
 this process has been remarkable, for here was a 
 
1 6 
 
 HALF-TONE 
 
 method which dispensed with the draughtsman, 
 working much quicker than the latter, and quite 
 distinct from the wood engraver. Anyone who is 
 familiar with the quickness and readiness of 
 American business routine can easily conceive that 
 the invention of the half-tone process was neces- 
 sarily a more important advantage for America, 
 than for slower-producing Europe. If we consider 
 further that industry and commerce is everything 
 there, and what is accomplished is mostly for these 
 purposes, whilst for art and abstract sciences 
 very little room is left, it is safe to conclude that 
 the process of Autotypy was required in the service 
 of industry for advertising purposes, and still 
 serves to that end. Advertising in America is a 
 very important word. Could we conceive an 
 easier, quicker, or more beautiful process for pro- 
 ducing a printing plate than by Autotypy. The 
 existing methods of swelled and wash-out gelatine 
 already employed for the purpose, even with 
 inferior negatives produced by bad screens, obtained 
 tolerable results. 
 
 It is only about nine years ago that the Moss 
 Engraving Co., of New York, as the first and 
 almost the only firm, nearly monopolised this pro- 
 cess in New York and far beyond its borders. One 
 can form some idea of the extensiveness of the 
 business, when we know that only to finish the 
 blocks, sixty-four men were employed as engravers. 
 
ON THE AMERICAN BASIS. 
 
 17 
 
 At that time the swelled gelatine process was at 
 its highest development and in its most flourishing 
 state. Etching was nearly ignored, because it was 
 at that time a rough and circumstantial method 
 held in very little esteem. Yet despite the faulty 
 screens, the inexperienced photographers, and 
 defective means of printing, astonishingly good 
 work was turned out. It was desired to imitate 
 the woodcut by making the lines not diagonal — 
 giving the same exposure to each set of lines — but 
 disposing them parallel to the sides, and giving the 
 horizontal a shorter and the vertical lines a longer 
 exposure. By this means one obtained in the high 
 lights definite points, but in the shadows horizontal 
 lines, which by their up and down swelling were 
 not unlike the long-trained or wavy lines of the 
 woodcut. Whilst the half-tones produced in this 
 way had the hardness of line work, they had also 
 some similarity to the cool, hard colouring of the 
 woodcut. 
 
 But it could not rest here. It was but 
 the beginning of the business. Such half-tone 
 blocks were expensive, but the high price was of 
 minor importance, so long as the production of 
 them lay in the hands of one maker. A much 
 more serious inconvenience was the waste of time 
 if quick delivery were desired. One could not wait 
 two or three days, but might well do so for as 
 many hours, and it was in this respect that the 
 
 B 
 
1 8 
 
 HALF-TONE 
 
 etching appeared of advantage. In the latter 
 process was found a helpful method of turning out 
 urgent work. Then commenced a battle between 
 the gelatine and the little-valued zinc. And 
 much despised was the latter. For instance, 
 the foreman of the swelling process department 
 of the Moss Engraving Co., pointed to an 
 etched zinc plate, a portrait in line work, and 
 laughing ironically said : " What a beautifully 
 dilapidated landscape ! " Since then the times have 
 changed very much, and the prejudice against 
 etched work has turned to the contrary. With 
 the improvement of the processes the time of pro- 
 duction of the plates has become shorter and 
 shorter, the work more and more beautiful, but 
 the price has gradually become worse and worse. 
 No one would use gelatine again except in certain 
 cases. Out of fifty engraving establishments in 
 New York, only one or two, so far as I know, 
 work, besides the etching, the wash-out process. 
 The swelled gelatine process has very properly 
 been abandoned entirely. The establishments 
 referred to use the wash-out process to make half- 
 tone blocks, and accomplish admirable work. A 
 third establishment has made use of the process 
 until recently for the reproduction of large books, 
 music, etc., but this work pays only in quantity at 
 a price which is hardly half that paid for etching 
 on zinc. Were we able to work even as quickly 
 
ON THE AMERICAN BASIS. ig 
 
 or nearly so quickly as on zinc, so that the finishing 
 of a plate, together with the necessary electrotype, 
 would not exceed one day, then the gelatine could, 
 in my judgment, compete with the zinc because 
 of its cheapness, and in many cases its beauty. 
 But the disadvantage remains of having to use 
 dense negatives. Very often we are not able to 
 make such a negative at all. Pencil drawings, 
 grey lithos, drawings in pale washes of colour or 
 ink, soiled, old, or yellowed paper, reproductions 
 of prints in blue colour, or on red or yellow paper, 
 or from very fine steel engravings, baffle all skill in 
 obtaining at the same time a fine and yet equally 
 dense negative. Besides, the advantage of zinc for 
 the making of colour blocks is indisputable. All 
 these causes turn the scale very heavily in disfavour 
 of the wash-out process. Again, if an establish- 
 ment be not very large, the existence of two 
 radically different processes, requiring, moreover, 
 double space, double arrangements, double labour 
 and wages, brings only disadvantages, and the 
 gelatine is, as we have pointed out, unable to exist 
 alone under present conditions. 
 
 Therefore zinc maintains the field in this long 
 battle, and has been used exclusively for the half-tone. 
 But this did not prevent a stand being made at the 
 last halting place in this process of development. 
 It was left for copper and the alloys of copper to 
 step in to meet the requirements of half-tone 
 
20 
 
 HALF-TONE 
 
 etching. The density and even texture of the 
 copper were recognised, as also its capability for 
 polishing, the easy way of etching it, and its 
 durability in printing. Here the firm of Moss has 
 the credit of bringing copper first into general 
 use. And when above all, in the enamel 
 preparations, a direct copying method was found 
 which for its beauty, its certainty, and its in- 
 destructibility, has quite outrun the albumen 
 process, it is not surprising that the copper etching 
 has found a place in every engraving business in 
 spite of the fact that only three or four years have 
 elapsed since the introduction of the process. 
 Copper being in America very little dearer than 
 zinc, there is not much to be taken into considera- 
 tion, so that the cost of the metal plays no part in 
 estimates of expense. What enhances the price 
 of the metals most is the polishing, but this is 
 mostly done by the etching firms in their own 
 establishments. Besides this, very pure copper 
 plates can be produced in an electrolytic way, so 
 as to make the expense very trifling in an estab- 
 lishment having an electrotyping plant. 
 
 As to the interior arrangements of American 
 engraving businesses, these are adapted to the 
 conditions imposed by intense competition, and 
 the work is carried on with the most reduced 
 labour, in the smallest space, and with the simplest 
 materials possible. The well-known American 
 
ON THE AMERICAN BASIS. 
 
 21 
 
 principle of division of labour finds here also its full 
 application and confirmation. The necessity of 
 confining the workrooms to a very small space 
 arises from the enormous value of the ground rents 
 in large cities. The most space is wanted, of 
 course, for the studio. The greater number are 
 daylight studios, and we find them generally on 
 the top floor. As most of the roofs are flat or with 
 very little inclination a part and sometimes a large 
 part of the roof is covered in with ground glass, 
 which gives a free entrance to the light. Very 
 often a part of the studio is without cover 
 at all, and the work is done in the open 
 air. On dull days which, of course, are more 
 rare in the sunny climate of New York than here, 
 the electric light in the form of arc lamps is made 
 use of. In all branches of industry use is made of 
 machinery, which fills the buildings from top to 
 bottom with machines of the most varied kind, and 
 which need a special system to supply the motive 
 power. Large buildings intended for industrial 
 purposes have their own engine standing in the 
 basement. Some of them are of several hundred 
 horse power, and these give by means of long 
 transmissions the necessary power to the busi- 
 nesses on the different floors. If there is no steam 
 power the steam is led from a central supply 
 station into the surrounding buildings at a very 
 low price. The gas meters of Otto Deutz are very 
 
22 
 
 HALF-TONE 
 
 much liked. They can be set in movement at any 
 time of day or night. The consumption of gas 
 is regulated automatically according to the neces- 
 sary power, and requires no supervision whatever. 
 With the low price of gas in New York the 
 expense of running these engines is unimportant, 
 and one is entirely independent of outside eventuali- 
 ties. Cleaner, but expensive in establishment, as 
 well as in cost of labour, is the use of electricity, 
 for which the Edison Co. possesses the monopoly 
 for New York, and exploits to the best advantage. 
 
 That there is much vibration with such a 
 mass of machinery is a matter of course, and the 
 violent shaking of the buildings makes a special 
 and careful arrangement of the photographic 
 apparatus necessary, especially as the studios are 
 mostly on the top floor. Of all constructions the 
 swing camera is the most approved, because of its 
 cheapness, comfort, and the little room it requires. 
 It gives to the American studio a typical character. 
 
 If several photographers have to work at the 
 same time in a dark-room, it is of advantage to give 
 the dark-room no door and to build an entrance 
 in the nature of a rectangular tunnel, which ex- 
 cludes the light sufficiently for the wet plate 
 process, and allows of the workers leaving and 
 entering without hindrance. For sensitizing the 
 plates dipping baths are generally used. The dark 
 slides for half-tone work are notable for their con- 
 
ON THE AMERICAN BASIS. 23 
 
 venience ; they have not the troublesome extra 
 carriers, yet they take every size of plate. The 
 negatives are washed best, most quickly, and at 
 the same time most economically under rose taps, 
 from which the water flows with a strong pressure, 
 but only plates prepared with albumen can bear 
 such a heavy shower. 
 
 The division of work in large studios is worthy 
 of attention. First the line and half-tone work is 
 separated and placed in the hands of different 
 operators, who have at their disposal a certain 
 number of cameras and separate dark-rooms. In 
 the half-tone process, which depends on very exact 
 working and the utmost possible cleanliness, the 
 photographer undertakes mostly the whole of the 
 work up to the finishing of the negatives. For the 
 taking of line originals very large firms have hardly 
 more than two photographers, each of whom has 
 several cameras at his disposal, and works them 
 all at the same time. It is not uncommon to find 
 good workers who, with the help of several boys, 
 have five or six cameras in active use at once. 
 One boy fastens the originals upon the copying 
 board, another prepares the plates, and a third one 
 intensifies them. The most important duties, such 
 as the focussing, the right exposure, and the 
 developing, the photographer undertakes himself, 
 besides supervising the other photographic opera- 
 tions, and in this practical, and at the same time 
 
24 
 
 HALF-TONE 
 
 economical manner, an enormous quantity of work 
 is turned out without excessive expense, because 
 the operations which cause the most waste of time 
 are done by boys at low wages. Also for turning 
 and stripping the negatives a boy is employed. 
 
 The studio, printing, and etching room are, of 
 course, absolutely separated to keep the dust of the 
 latter away from the first. On the arrangement 
 of the room for direct printing there is nothing new 
 to say. The essential features are : Whirlers and 
 copying frames, of which there are a number of 
 good make. The etching also is primitive. A heat- 
 ing stove composed of an iron plate heated under- 
 neath with gas, the etching tubs, dusting boxes, 
 a stoneware or lead trough for potash solution, a 
 few rollers and ink slab for occasional use, brushes, 
 sponges, etc., makes up the whole arrangement. 
 
 The methods of etching are radically different 
 from those customary in Germany. First of all, 
 rolling-up and covering in with ink, and also the 
 deep or finishing etch is omitted. The maximum 
 time allowed for etching a line plate of fair size, 
 say, for instance, of 14x18 inches, must not ex- 
 ceed, with a good worker, two hours, whilst urgent 
 and small-sized work has to be etched in half or 
 three-quarters of an hour. Deep etching is com- 
 pensated for by the routing machine, which has 
 been naturalised from the commencement of photo 
 engraving. Besides the router there are running 
 
ON THE AMERICAN BASIS. 
 
 2.5 
 
 a host of other machines, of which the most im- 
 portant are the circular saw, the polishing machine, 
 the wood trimmer, the bevelling machine, and the 
 drilling machine. 
 
 Much care is taken in the selection of hand 
 printing presses ; the most preferred being the 
 Washington Press. The art of proof-taking has 
 obtained a high degree of perfection, and good 
 provers are well paid. Mechanical printing has not 
 been introduced, perhaps because of the original 
 unevenness of the plate and the further inequalities 
 made purposely by the burnisher of the engraver, 
 which renders special hand pulling necessary. 
 
 Perhaps it will be interesting to many to know 
 the average wages earned by workers employed in 
 an engraving establishment in New York, but as a 
 matter of course we do not refer to exceptional 
 salaries. A capable half-tone photographer earns 
 from £5 to £7 a week; a line photographer £2 10s. 
 to £3 ios.; a printer, well up in albumen and 
 enamel process, £2 ios. to £3 ios. ; an etcher in 
 line and half-tone on zinc and copper, £3 to 
 £4; boys for washing the glass plates, making 
 silver prints, or otherwise employed in the studio, 
 copying or etching room, earn from 12s. to 30s. 
 according to their knowledge and qualification ; a 
 retoucher for negatives or prints, £2 ; capable 
 engravers, knowing how to cut vignettes, ^4 to £5 ; 
 line engravers, £3 to £3 15s., and the same for 
 
26 
 
 HALF-TONE 
 
 provers. A man working the routing machine 
 gets £2 15s. to £ 3 10s. ; a blocker, who fastens 
 the plate on to the blocks, £2 10s. to ^3 : a plate 
 polisher, £2 ; and a carpenter, £ 3 
 
 The price paid for blocks has dropped in the 
 last few years very low, and the golden time in this 
 branch belongs to the past. The competition is 
 overwhelming. It should be remembered that in the 
 City of New York alone there are more than fifty 
 establishments. By all of them beautiful and rapid 
 work is done, but thus the public is spoilt, and the 
 customer screws his claims always lower. Not- 
 withstanding this, it must be said that photo- 
 engraving is flourishing. We must not forget the 
 requirements, not only of the huge population of 
 three millions in the city, but also of the inland 
 States, from whence many orders come. Further- 
 more, the methods of working have been more and 
 more improved, the workers becoming more 
 accustomed to the routine, whilst with the improve- 
 ment of the businesses within, the aptitude for 
 production has grown, so that against the low 
 prices for the blocks a cheaper rate of production 
 can be opposed. The average price for blocks in 
 line is about 3 Jd. to 5|d. per square inch ; those 
 for half-tone, irrespective on what metal they are 
 engraved, is. ; and for vignettes the price is is. 3d. 
 per square inch. For plates of very small size a 
 minimum is charged. 
 
27 
 
 CHAPTER I. 
 
 APPARATUS FOR NEGATIVE MAKING. 
 
 Alike in all photographic andphoto-mechanica 
 processes the negative is the most important fatter 
 for obtaining a good ultimate result, and the pro- 
 duction of a succession of good negatives of all 
 subjects taken in hand requires the utmost care, 
 skill, and intelligence. In the same way the 
 reproduttion of an original by the half-tone process 
 also depends for its success for the most part on 
 the quality of the negative. Once in possession 
 of a good negative the subsequent processes are 
 easy. In consequence of this fact the centre of 
 gravity in an establishment is in the arrangement 
 of the photographic department, and by reason of 
 the importance of this part of the work no expense 
 is spared. 
 
 The first requirement in a studio intended for 
 working the half-tone process is a strong and even 
 light, and the best is where there is free entrance 
 of direct sunlight. I know many of the establish- 
 
2 8 
 
 HALF-TONE 
 
 ments in New York, but I cannot say that they 
 possess any particularly practical feature in the 
 arrangement of their studios. Nearly all of them 
 are in the highest part of the building. To obtain 
 light a large part in the roof, which is only slightly 
 inclined, is cut out and the opening filled in with 
 more or less transparent or ribbed glass. Some- 
 times the studio is very high, so that though there 
 may be a considerable area of glass only a small 
 amount of light reaches the floor. In this case a 
 proportionately high platform is built up. Several 
 establishments have cameras permanently on the 
 roof so as to work by dull light in the open air. 
 All deficiency of daylight is met by the electric 
 light, and we could not conceive of a rational 
 establishment without this illuminant. The lamps 
 hang between the cameras, in front of the copying 
 board, and are of 1500 to 4000 candle power. They 
 are provided with reflectors to illuminate the original 
 evenly. Instead of hanging the lamps they are 
 sometimes supported on moveable stands (figs. 1 & 2) 
 so that they can be placed in front of the original 
 in any desired position. One or two establish- 
 ments work without daylight and are wholly 
 dependent on artificial light. If the electric light 
 is not so strong as good sunlight it has neverthe- 
 less the advantage of being much more constant 
 than daylight. The electricity is sometimes 
 taken from the mains, but other establishments 
 
ON THE AMERICAN BASIS. 2Q. 
 
 generate it on the premises by means of 
 dynamos. 
 
 The reproduction establishments being, as be- 
 fore mentioned, in the highest part of the buildings, 
 
 Fig. i. Fi g- 2 - 
 
 which are sometimes ten to nineteen stories high, 
 it occurs that in such colossal buildings where 
 machinery of 100 to 400 collective horse power are 
 running, that there is a continual vibration, and 
 
HALF-TONE 
 
ON THE AMERICAN BASIS. 
 
 3 1 
 
 this requires a special and careful arrangement of 
 the camera stand. Of the apparatus in use the 
 hanging or swing camera is the most favoured, 
 and fig. 3 shows the most popular shape. Close 
 to the glass roof and running parallel with it is a 
 rafter or iron bar, and the cameras are at such a 
 
 Fig. 4- 
 
 distance from one another that an easy movement 
 of the operator is possible. The bed on which the 
 camera is moved to and fro is composed of a long 
 rigid frame (fig. 3), or of narrow planks of dry 
 wood placed on edge (fig. 4). The length depends 
 
32 
 
 HALF-TONE 
 
 on the focus of the lens used and the size of the 
 originals, ranging between eight and twenty feet. 
 On one end of the frame is the copying board for 
 the originals to be reproduced ; it may be movable 
 or fixed, and is a flat board 
 running in a groove. It keeps its 
 position by means of a spring. 
 To place the original quickly under 
 glass the arrangement illustrated 
 in figs. 4 and 5 is used. On the 
 top and bottom edge of the copying 
 board are two channels formed of 
 long strips of wood. To mount the 
 original the board is taken off, and 
 laid down, the drawing being then 
 placed in position, and a thick piece 
 of plate glass put upon it. Two 
 narrow strips of wood of the same 
 length as the board and with tapered 
 ends are laid over the edges of the 
 glass plate at each end, the tapered 
 ends being under the groove at 
 the top and bottom of the board, 
 where they are fastened with small 
 wedges. The pressure of the wooden 
 strip is sufficient to hold the glass plate 
 when the board is brought to its vertical 
 position. This arrangement is so easy and 
 quick to handle that it seems to me worth 
 
ON THE AMERICAN BASIS. 
 
 33 
 
 describing. Care must be taken to avoid the light 
 coming direct from the front, otherwise a reflection 
 on the glass is unavoidable. The frame on which 
 the camera stands is suspended with four iron 
 bands or wire rope to a second beam of the same 
 length, but of very little breadth, in order to avoid 
 as much as possible the formation of a shadow on 
 the original, and the whole swings free on a wire 
 rope hanging from the iron rail or rafter. As the 
 centre of gravity changes by shifting the camera 
 on the swing, the base is kept a little sloping, to 
 allow the light to fall as much as possible vertically 
 on the original, and a running weight of about 
 100 lbs. is attached to a tightly extended wire rope 
 running the whole length underneath the base of the 
 camera. Such a swing arrangement destroys all 
 vibration. The camera can be directed as required 
 to the light, and no blurring is to be feared through 
 anyone knocking against the swing. It is even of 
 advantage when using the electric light to keep up 
 a swinging movement to avoid reflections or uneven 
 light. Other constructions seek to avoid vibration 
 by means of springs and indiarubber bands. Figs. 
 6 and 7 give representations of these arrange- 
 ments. The last one I know by my own ex- 
 perience, and have tested by working it for a long 
 time. One establishment in New York uses a 
 peculiar kind of floating or water-balanced camera, 
 but I do not know anything particularly about this 
 
34 
 
 HALF-TONE 
 
ON THE AMERICAN BASIS. 
 
 35 
 
 construaion. Under all circumstances the swing 
 is unsurpassed for its cheapness and simplicity, and 
 I cannot see any reason for preferring any other 
 system. 
 
 Besides the camera, the construction of the 
 dark slide is of great importance. A good dark 
 slide for half-tone work must have the following 
 features. It must be possible to make use of the 
 
 Fig. 7- 
 
 full size of the screen, and of the negative, within 
 the size of the camera. The screen and plate must 
 stand quite parallel and not closer than i mm. 
 distance one from the other. Otherwise the silver 
 finds its way into the cementing of the screen. 
 Further it must be possible to easily regulate the 
 distance of the plates without shifting the focus 
 and parallelism. There has not been made until 
 now any dark slide having all the qualities required, 
 
36 
 
 HALF-TONE 
 
 and many establishments are satisfied with very 
 simple arrangements. Certainly the process can 
 be worked with an ordinary dark slide, but the 
 chances of obtaining a good result are lessened, 
 whilst such makeshift means, with the resulting 
 failures, combined with the vexation and dis- 
 appointment of the worker, makes one consider 
 the price of a suitable half-tone dark slide not too 
 high. If an ordinary dark slide is used for half- 
 tone the necessary distance from the wet plate is 
 obtained by interposing strips of cardboard or 
 by fixing drops of wax at the corners of 
 the screen, and after focussing to rack in 
 to the extent of the thickness of the screen, 
 plus the chosen distance, towards the front. 
 This is the most simple and not the worst of half- 
 tone dark slides. Of course, the size of the wet 
 plate must not exceed that of the screen, and the 
 screen cannot be used up to its full size. Besides, 
 in the matter of sharpness, the shifting of the 
 ground glass does not allow of very sure working. 
 Should it be desired to avoid shifting the focus, the 
 position of the carriers taking the screen and nega- 
 tive must be changed in such a manner that the 
 screen is held in a deep rebate by means of springs, 
 and is pushed up again, the four silver corners 
 holding the negative. Little pieces of cardboard 
 fixed on the corners enables the regulation of the 
 distance to be made. 
 
ON THE AMERICAN BASIS. 
 
 37 
 
 To use the full size of the screen, the size of 
 the sensitive plate must exceed the screen in every 
 way by about an inch. Both the screen and the 
 sensitive plate must be separately fastened in their 
 respective positions. As things are, the use of 
 carriers has no particular advantages. Without 
 considering the number of them which have to be 
 always at hand for the different sizes, they are 
 always warping and shrinking, owing to the 
 weather and temperature, and for half-tone pur- 
 poses, where exact parallelism is needed, this 
 renders them almost useless. Besides they bend 
 very easily by the pressure of the springs, and 
 cause soiling of the screen by silver, even if not 
 sticking to the collodion film. This inconvenience 
 is avoided in America by the generally used 
 Bensterand Bonanza dark slides, which arrangement 
 fig. 8 illustrates. The cogwheel movement in the 
 Benster dark slide is not necessary, the cross- 
 piece on which the plate rests being fixed in the 
 desired position by means of notches (fig. 9). The 
 top cross piece moves in grooves up and down. 
 All sizes within the frame can be used with these 
 dark slides. If a screen holder is placed between 
 the sensitive plate and the shutter of the dark slide 
 we have then a dark slide for half-tone answering 
 very well for the purpose. The most perfect half- 
 tone dark slides up to date are Levy's patent. 
 They permit the use of different sizes of screens 
 
38 
 
 HALF-TONE 
 
 and plates, and the distance is regulated 
 by an outside arrangement. This dark slide is in 
 a certain measure a double Benster dark slide, the 
 arrangement for the screen holder being the same 
 as for the negative. An ingenious adjustment 
 
 Fig. 8. 
 
 system, which is worked by two buttons 
 from the outside of the dark slide, enables the 
 distance to be varied to about i cm., and also to 
 be enlarged whilst exposing, a circumstance 
 which will be referred to later. Ingeniously 
 as these dark slides are constructed they are not, 
 
ON THE AMERICAN BASIS. 
 
 39 
 
 to my mind, entirely satisfactory. On the one 
 hand such mechanism is so much more easily sub- 
 jea to deterioration, the more complicated it is ; 
 on the other hand, because such an exactness of 
 parallelism as the use of a half-tone screen requires, 
 
 Fig. 9. 
 
 exceeds any demand that can reasonably be 
 required of a camera maker, and because the screen 
 cannot be brought closer to the wet plate than 
 determined by the mechanism. It is always better 
 to have a hand one's self in the regulation of the 
 position of the screen. This can be done by the 
 
4 o 
 
 HALl'-TONE 
 
 arrangement illustrated in fig. 10 and n. It 
 shows in principle a simplified Levy dark slide, 
 with the difference that the fixing of the screen is 
 obtained by four movable screws. 
 
 Of all necessaries for half- 
 tone work the matter of the 
 screen claims the highest interest ; 
 and with good reason, for nothing 
 exercises a more lasting influence 
 on the result than does the screen. 
 Now that in Europe the paper 
 
 i 
 
 FJf. 10. Hg . u.* 
 
 screen seems to be in the dying out stage, it is useless 
 
 * It not being easily possible to alter the German words 
 on this diagram block, it may be stated here that " Raster " 
 is Screen, and " Nasse Platte " Wet Plate.— Trans. 
 
ON THE AMERICAN liASlS. 
 
 41 
 
 to waste words over this rudimentary process. The 
 progress of half-tone is intimately associated with 
 progress in the manufacture of screens, and we can 
 only speak of the consequences of laying aside the 
 paper screens, and of the work since the use of 
 original glass screens or copies of them began. 
 All the progress in the printing and etching pro- 
 cesses, in the education of a new school of special 
 operators, and in the training of etchers and proofers, 
 have not contributed so much towards raising the 
 interesting and beautiful half-tone process to the high 
 position which it now occupies in America, as has the 
 progress made in the production of suitable screens. 
 With these, stands or falls the half-tone process. 
 We have given up the single lined screens which 
 had to be crossed during exposure, and the question 
 as to the proportion of black and white lines 
 has also been decided. Not less has experience 
 taught us to what degree of fineness the screens 
 may be used without asking more of the printing 
 press and ink and paper than they can render. 
 Since it has been possible to obtain good screens 
 comparatively cheap, the half-tone process has 
 made unexpected progress, giving a flourishing 
 life to many establishments. 
 
 The most preferred and most appreciated are, 
 very rightly, the glass screens of Max Levy, of 
 Philadelphia. So far as the patented process of the 
 manufacture is known, faultless polished plate glass 
 
42 
 
 HALF-TONE 
 
 is coated with an etching ground — perhaps com- 
 posed of asphalt, indiarubber and turpentine — and 
 ruled in one of Levy's improved line machines, by 
 means of a suitably ground diamond, the surface of 
 the glass being bared. The machine must not be 
 interrupted in its progress for a moment, as every 
 interruption leaves a perceptible fault in the regu- 
 larity of the ruling and spoils the plate. Of course, 
 everything depends on the composition of the 
 coating, in fact, upon it depends the fineness and 
 sharpness of the lines. The diamond* cuts through 
 the coating without injuring the glass, and the 
 plate is afterwards exposed for a short time, about 
 two minutes, to the action of fluoric acid. After 
 removing the coating, the plate is covered with a 
 black film, and the excess of colour afterwards 
 removed by means of a polishing machine so that 
 the black remains only in the etched parts. Two 
 plates with their lines crossed are then cemented 
 together with Canada balsam under hydraulic 
 pressure, and after grinding the edge the screen is 
 finished. As a matter of course . such screens if 
 carefully handled are very durable and not easily 
 attacked by silver. As a rule the thickness of the 
 transparent and opaque lines are the same, or does 
 not exceed the proportion of two of the latter to 
 three of the former. These screens are manu- 
 factured in all sizes and shapes, and vary between 
 75 and 240 lines to the inch. They are of unsur- 
 
ON THE AMERICAN BASIS. 
 
 43 
 
 passed transparency and sharpness, and only one 
 who has never handled a Levy screen would say 
 that screens etched with fluoric acid have ragged 
 lines. Whilst original screens are preferable to 
 copies, Wolfe, of Dayton, Ohio, nevertheless, 
 makes good screens produced by means of collodion 
 dry plates, and these are much below the price of 
 Levy's. Many establishments in America use 
 these screens exclusively, and the results obtained 
 with them are hardly to 
 be distinguished from 
 those obtained with origi- 
 nal screens. 
 
 From the way of man- 
 ufacturing these screens 
 it will be understood that 
 they are composed of a 
 network of black lines, 
 crossed at right angles, 
 forming square transparent openings (fig. 12). 
 Until now this kind of screen has been used with 
 advantage for the half-tone process, and my subse- 
 quent remarks will relate only to this type of 
 screen. I may mention, however, that screens 
 have been made which are the negative of the 
 beforementioned, having rectangular crossed 
 transparent lines and opaque squares; also a 
 system of round opaque dots on a transparent 
 ground, or the contrary, transparent grain on an 
 
44 
 
 HALF-TONE 
 
 opaque ground. To obtain more modulation from 
 a fiat original, Gaillard recommends screens com- 
 posed of two engraved plates, each with semi- 
 opaque single lines, which are sealed together. By 
 this means a three-fold tone is obtained — trans- 
 parent, semi-transparent and opaque — the points 
 where the lines cross having a double density. 
 These different forms of screens are almost alto- 
 gether discarded, as they are for the most part 
 without advantage over the American screen, even 
 if the execution were faultless to the same degree. 
 But the method of exposing through a single line 
 screen, and after the first half of the exposure 
 turning the screen for 90 degrees, is of importance, 
 and has been practised until recently by large 
 establishments with the best results, till at last 
 even there the crossed screen conquered the field. 
 
 Whoever finds himself in the position of 
 having to decide on a screen should for general 
 work not get anything finer than 1 50 lines to the 
 inch nor coarser than 75. On the one hand, by 
 working with fine screens the difficulties of the 
 process increase enormously, and the prints from 
 the blocks on the machine do not turn out in most 
 cases so well, except when the best paper and the 
 most expensive ink is used. On the other hand, 
 with coarse screens there is too much loss of fine 
 detail. The following are the prices of the various 
 makes of cross-lined screens : — 
 
ON THE AMERICAN BASIS. 
 
 45 
 
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ON THE AMERICAN BASIS. 
 
 47 
 
 Screens are also made in my instruction establish- 
 ment from original American ones by photography 
 and sold at one penny per square centimetre. 
 
 Every original can be reproduced by the half- 
 tone process, but not all give equally good results. 
 Indian ink or sepia drawings, good and clean 
 photos, burnished, but not with high gloss— nor 
 cracks nor spots (particularly if of a yellow or 
 greenish nature)— and with detailed shadows, can 
 be beautifully reproduced. In retouching, the 
 work should be broad in effect, without going into 
 minute detail, and in this way one can learn to 
 brighten up a bad original by washes of colour. 
 The most difficulty is experienced with dirty skies 
 in landscapes, and damaged backgrounds in 
 portraits. In such cases the parts are painted over 
 with white pigment, or they are cut out and the 
 picture pasted on white cardboard, or white paper 
 is pasted over the sky and the contour, with such 
 projections against the sky as lightning conductors, 
 leaves and branches of trees, etc., drawn in. 
 It is entirely left to the taste of the artist to insert 
 clouds or smoke from the chimneys, to put in 
 lights, introduce figures, or work up shadow detail, 
 giving the picture a more picturesque and lifelike 
 appearance. Delicate modelling in the lighter 
 tones, such as the folds of drapery is almost lost 
 in reproduction, but through retouching a stronger 
 effect may be produced, It is further recom- 
 
+8 
 
 HALF-TONE 
 
 mended to burnish badly mounted photos, or in 
 the case of cracked albumen prints to rub them 
 with glycerine. If unmounted and crumpled 
 photos are sent in they should be squeegeed down 
 like gelatine pictures on to collodionized glass, 
 receiving thereby a high brilliancy. They may be 
 copied through the glass or pasted on to it like a 
 cardboard mount. Of photographic papers the 
 collodion is the most advantageous to use on 
 account of its unusually clear and detailed shadows, 
 its exceedingly sharp detail and its structureless 
 film. It is not absolutely necessary to tone the 
 pictures, but it is preferable, because it increases 
 the brilliancy, the intense red of the untoned prints 
 prolonging the exposure very much. Originals 
 in line can be copied with the screen very well, and 
 give plates of highly artistic feeling. 
 
 One word on lenses suitable for half-tone. 
 The light has to pierce the thickness on the screen 
 and to diffuse behind it, whilst contrary to line 
 copying, where clear lines only have to act, the 
 shadows have also to reflect so much light on to the 
 sensitive plate that a fine, but dense dot is pro- 
 duced. Lenses giving poor illumination are 
 therefore not suitable. An ordinary rapid recti- 
 linear landscape lens renders good service. In 
 general, quick- working lenses giving with large 
 apertures an evenly-illuminated, well-defined, and 
 not too soft picture, are the most suitable, 
 
49 
 
 CHAPTER II. 
 
 THE NEGATIVE. 
 
 I turn now to the description of the most 
 interesting and important part of the work, namely, 
 the production of the negative. I presume that the 
 operator is in possession of a not too hard-working 
 collodion, as well as a strong and perfect silver 
 bath, and is well acquainted with the handling of 
 wet plates. Until gelatine plates can be made 
 which are as rich in contrast, transparency and 
 sharpness, and can be developed, intensified, and 
 dried in the same time as wet plates, there is no 
 hope of using them for half-tone work. Any 
 collodion is suitable that will work clear and 
 strong, and it is superfluous to give a new recipe. 
 Every operator swears by his own formula. In 
 reality the success depends less on the composition 
 of a determined solution than upon an intimate 
 knowledge of its qualities, and the extent of the 
 practical experience of the operator. 
 D 
 
5« 
 
 HALF-TONE 
 
 The demands of a half-tone negative are of a 
 varied nature. It is similar to an ordinary portrait 
 or landscape negative, in that it must be exposed, 
 developed and printed, but the half-tone negative 
 must be also treated in accordance with the follow- 
 ing processes to which it is subject. It has not 
 only to render the high-lights, half-tones and 
 shadows of the original in their relative tone value, 
 but within these limits it has to take into account 
 the conditions imposed by the making of the 
 printing plates. If the process of making them is 
 by etching, then it is evident that the lights of the 
 negative have to be more open, because the etching 
 liquid strives to round off and reduce the dots. It 
 is quite indifferent whether a short first etch is 
 given, the surface of the plate representing the 
 picture being then protected with resin against the 
 action of the etching solution, and then deep 
 etched, or whether the plate is etched through in 
 one bath. In the latter case the encroachment is 
 not prevented, it is even preferred that the dots in 
 the lights etch a little finer. The negative has to 
 take these circumstances into account. 
 
 Suppose the negative has to be printed on to 
 chromated gelatine and the latter washed out, it 
 follows from the action of the light, with the 
 necessarily prolonged exposure, and the conical 
 penetration of the rays, that to print the dots large, 
 the negative should be as far as possible rich in 
 
ON THE AMERICAN BASIS. 51 
 
 contrast and plastic in the high-lights. If we con- 
 sider further that in the electrotype made from the 
 gelatine relief the shadows come always a little 
 more shallow than in the matrix, this circumstance 
 has to be accounted for by giving detail to the 
 shadows. The differentiating of the negatives can 
 be pushed much further by taking into considera- 
 tion the fact that the zinc produces clearer, and 
 somewhat harder proofs than copper, which print 
 softer and fuller in tone, but differences are so 
 imperceptible that while a photographer may talk 
 about such distinctions he cannot carry them 
 through practically, because other much more 
 important difficulties require his whole at- 
 tention:* 
 
 Besides the considerations of modelling, and 
 the applicability to block making, the negative has 
 to accomplish a third condition, the complete 
 breaking up of the tones into sharp, black, opaque 
 dots and lines. A perfect half-tone negative must 
 be free from all greyness, unsharpness, or veiling in 
 the dots. Next to the deepest shadows, which 
 for the most part have to be left transparent 
 without dots, there should commence to form a 
 fine, sharp, black dot, the size of which increases in 
 the middle tones, until in the high-lights it joins by 
 a ragged line to its neighbouring dot, producing a 
 clear opening, and spreading in the highest lights 
 into increasing size (fig. 13). 
 
52 
 
 HALF-TONE 
 
 In the production of such negatives, in which 
 the three requirements are fulfilled of faithful 
 rendering of the original, 
 adaptation to the method of 
 block making in use, and the 
 exact breaking up into black 
 and white, there are some 
 hypotheses to be noted, 
 which I will proceed to ex- 
 plain. 
 
 If a bundle of rays of 
 light falls perpendicularly 
 on the plane of a slit, we 
 observe on a screen placed 
 behind and directly opposite 
 to it, not the sharp image of 
 the slit which we perhaps 
 expected, but a lighter centre, 
 surrounded by a darker 
 zone, the light of which 
 decreases to nil towards 
 the borders. That is to 
 say, the motion of the light 
 which reaches the slit creates 
 there new waves of spherical 
 form, which spread beyond 
 the opening, and in this 
 manner produce the veiled images of the slit. 
 Let us suppose, now, the half-tone screen as an 
 
 • • • 
 
 Fig. 13- 
 
ON THE AMERICAN BASIS. 
 
 53 
 
 accumulation of numerous slits, through which the 
 light falls on the sensitive plate ; the same appear- 
 ance of light distribution will happen here. From 
 every opening in the screen comes forth a diverging 
 bundle of rays of which the maximum of light lies 
 in the centre, corresponding to a central point, with 
 a darker fringe on the sensitive plate. With the 
 strength of the light the divergence increases or 
 decreases, and by the uneven illumination of the 
 screen, dots are produced, not only of different 
 intensity, but also of different size. There is 
 formed on the sensitive plate not only the reversed 
 image of the screen, with equally large but un- 
 equally intense dots, as we might at first surmise, 
 but actually there is attained in the camera a 
 picture in dots, and as the dots come together by 
 increasing in size, these are lines of different size 
 and thickness, yet formed by means of a network 
 with openings of the same size. 
 
 Result of Differently Distancing the 
 Screen. — The possibility of the rays diverging 
 behind the screen presupposes a certain distance 
 between the latter and the sensitive plate, and it is 
 clear that by increasing or decreasing this distance a 
 change takes place in the size and the sharpness 
 of the dots. The greater the distance, the more 
 opportunity has the cone of light to diverge on its 
 way from the screen to the sensitive plate (see fig. 
 14), but at the same time the dots lose their sharp- 
 
54 
 
 HALF-TONE 
 
 ness. On the other hand, by decreased distance 
 dots of greater sharpness and smaller size are 
 formed, and if the distance is nil — that is to say, if 
 screen and sensitive plate are in contact — an un- 
 evenly graded negative will be the result. It is 
 evident that the original to be reproduced can be 
 rendered with a different appearance according to 
 the chosen distance. If the original has very deep 
 
 Screen 
 
 Wet Plate 
 
 Wet Plate 
 
 Fig. 14. 
 
 shadows and chalky lights, it is advisable to keep 
 back the diffusion of the lens by decreasing the 
 distance. Naturally, the detail of the shadows can 
 only be obtained by prolonged exposure. But this 
 does no harm to the lights, because here, in conse- 
 quence of the short distance, the excess of exposure 
 is more to the advantage of the density than the 
 divergence or joining up of the dots. Whilst we 
 have at hand, in this way, a means of softening 
 
ON THE AMERICAN BASIS. 
 
 55 
 
 contrasts, this can also be augmented by increasing 
 the distance. This is to be preferred with a soft 
 flat original. But we must take into consideration 
 that increase of distance goes hand in hand with a 
 prolongation of exposure. Behind every opening 
 in the screen extends a conical ray of light, which, 
 by diffusing over a larger surface, naturally 
 increases in intensity. The latter is just what is 
 desired in the lights. That, in spite of prolonged 
 exposure, the shadows remain clear, is also partly 
 caused by the dispersal of the light. In this 
 process, where we have to work with an already 
 feeble light action, the dispersal of the rays further 
 weakens the effect ; this results especially when 
 using a greater distance. Should we thus require 
 an action of the light to take effect in the shadows, 
 a prolonged exposure is necessary. The choice of 
 increased distance is further advised generally if 
 the process of printing requires strong negatives, 
 rich in contrast, with closed lights ; for instance, in 
 the swelled gelatine and wash-out gelatine process, 
 and in the case of many enamel preparations 
 having strong relief. The dots in the lights of the 
 negative round off more, and it is relatively easy 
 to obtain an evenly dense closing up between the 
 dots. Good strong light is requisite, so that we 
 have not to give a disproportionate exposure, when 
 it is necessary to use small stops, to which I shall 
 refer later on. With feeble light it is not possible 
 
56 
 
 HALF-TONE 
 
 to break up the shadows sufficiently, and it will 
 always give, with a large distance of the screen, a 
 hard negative. 
 
 The Effedt of Different Sizes of Stops 
 and the Focus of the Lens— The position 
 of the screen is not the only means available 
 of modifying as desired the character of the 
 negative. A more simple and certain method 
 
 Screen » 
 
 Wet Plate 
 
 Fig. 15- 
 
 is to take advantage of the circumstance 
 that different sized stops, by equally long 
 exposure, produce different sized dots. If the 
 light passes through the full aperture of the lens, 
 the angle of incidence is greatest, but gradually 
 decreases by the use of smaller stops. If we now 
 interpose in the path of the rays a screen through 
 which the light passes in straight lines, but diverges 
 
ON THE AMERICAN BASIS. 
 
 57 
 
 on the other side, the angle at which the light 
 strikes the screen and passes through its openings 
 must influence the result. Nearly parallel rays, 
 such as pass through small stops, will produce less 
 spreading artion behind the screen than rays 
 coming more obliquely from large stops, these 
 latter being further diffracted behind the screen, as 
 
 Screen 
 
 Wet Plate 
 
 Fig. 16. 
 
 will be seen in figs. 15 and 16. Besides this, the 
 sideways spreading behind every opening increases 
 with the strength of the light. From these two 
 farts, as well as the general experience that small 
 stops produce soft, and large stops harder nega- 
 tives, it follows that by changing the diameter of 
 the stops a different effecT: in the half-tone negative 
 is produced. In fart, negatives exposed through 
 
5« 
 
 HALF-TONE 
 
 large stops, even with a short exposure in propor- 
 tion to the diameter of the stops, give more 
 contrast than those exposed with smaller stops, 
 and one is able to obtain by proper choice of stops 
 every desired modification of strength or softness 
 in negatives from hard or feeble originals. The 
 action of the stops can be summed up in the 
 following words: Small stops give the shadows, 
 and large stops give the lights. We have, there- 
 fore, an action equivalent to placing the screen at 
 different distances, and the operator has at com- 
 mand a most effective means of breaking up the 
 tones, and inducing the modulation of the dots. 
 The choice of suitable stops for the purpose is, 
 therefore, of primary importance. 
 
 For the same reason— viz., that the rays fall 
 at an oblique angle— lenses with short focus give . 
 more contrast than those with long focus. One 
 must, in this case, work, as a rule, with a 
 shorter distance between the screen and sensi- 
 tive plate, or use a smaller stop, a circumstance 
 which has to be taken into consideration when 
 working new and unknown lenses. 
 
 The Action of Different Shapes of 
 Stops. — The appearance of the dot in the half- 
 tone negative is influenced by two factors, namely, 
 in a slight measure by the shape of the opening in 
 the screen, and in a far greater degree by the shape 
 of the stop. Suppose the screen and the sensitive 
 
ON THE AMERICAN BASIS. 
 
 59 
 
 plate are in contaft, there is produced in the 
 negative a dot of exaftly the same shape and size 
 as the openings in the screen. As we have already 
 seen, the dots undergo from different causes, with 
 increasing distance of the screen, changes in size, 
 and not less is the shape altered, indeed, if we 
 examine a negative exposed with an ordinary round 
 stop we find besides the reproduftion of the drawing 
 of the original not square black 
 
 dots but perfectly round ones. 
 
 For the explanation of this 
 
 appearance we must conceive an 
 
 aperture of the screen, placed at a 
 
 certain distance from the sensitive 
 
 plate and from the stop, as forming 
 
 the system of a pinhole camera. 
 
 The dots on the negative are, 
 
 indeed, nothing else but minute 
 
 images of the opening in the Fig. 17. 
 
 diaphragm . By using other shapes 
 
 of stops, variously shaped dots will be the result, 
 
 but it will be noted from my subsequent remarks 
 
 that in consequence of the lateral spreading behind 
 
 the screen the dots always tend to approach a 
 circular shape. To carry out some beautiful 
 experiments on this point a piece of tissue paper is 
 fastened over the lens, and the camera exposed 
 directly towards a window. According to the 
 desired size of the dots a longer or shorter 
 
 ♦ 
 
6o 
 
 HALF-TONE 
 
 exposure is given through stops cut out of 
 paper. 
 
 If a square stop (placed in a position corres- 
 ponding to the openings of the screen) is chosen, 
 the aclion is very little apparent, the dots preserv- 
 ing essentially their spherical shape, but an 
 evident tendency will be perceptible towards a 
 prolongation in the direction of the corners of the 
 stop. If we make a square stop with the sides a 
 
 Fi ^ l8 - Fig. I9 . 
 
 little concave (like fig. 17) the efferft is surprising. 
 Squares are formed, which in accordance with the 
 position of the stop have a definite situation to 
 each other. If the diameter of the stop is parallel 
 to the lines of the screen the dots turn their corners 
 towards each other (fig. 18). But if the diameter 
 of the stop cuts the lines of the screen at an angle 
 of 45 degrees, then the squares in the negative lie 
 as in fig. 19. Similar, but somewhat more charac- 
 
ON THE AMERICAN BASIS. 
 
 6l 
 
 teristic, is the effect of using the cross-shaped stop 
 (fig. 20). One can in this manner devise numerous 
 variations, but most of them are only interesting as 
 amusement, and without practical value. For 
 instance one can obtain with a double slit stop, a 
 negative with double the number of lines 
 possessed by the screen. Only two shapes of stops 
 of this nature offer any advantage, viz., the single 
 and crossed slit stop. If we 
 choose an oblong shape with the 
 sides parallel to the lines of the 
 screen, oval shaped dots in the 
 direction of the stop are the result 
 (fig. 21), and these with a suffi- 
 ciently long exposure join and 
 form wavy lines. If the stop is 
 altered in such a way that the 
 slit decreases in the centre, as fig. 
 22 shows, the result will be equi- 
 valent to a single lined screen with 
 sharp straight lines as fig. 23. If two of these 
 slits are crossed at right angles as fig. 24, and ex- 
 posed under the same conditions of parallelism 
 with the lines of the screen, the result will be the 
 highly interesting and remarkable fact that we 
 obtain from a positive screen a positive image, and 
 by correct experimental conditions the result will 
 be black straight lines as fig. 25. If intensified 
 and, when dry, covered with a protecting glass, 
 
 Fig. 20. 
 
6 2 
 
 HALF-TONE 
 
 the plate can be used as a working screen. 
 
 The question is, which is the best stop for 
 half-tone reproduction. Such a stop should 
 modify the dots in the lights in such a manner as 
 to bring about a spreading and intimate joining 
 
 Fig- 21. Fig. 22. Fig. 23. 
 
 together at their four corners. This is obtained 
 by the pointed square or the cross-shaped stop. 
 In the shadows we have to direct our efforts to 
 concentrating the rays on the smallest possible 
 surface. This is obtained by the round stop. A 
 stop which is between these two forms will do the 
 
ON THE AMERICAN BASIS. 
 
 63 
 
 best service. Of the numerous possible stops those 
 having about the shape of figs. 17 and 26 will 
 answer best for the purpose. But we have to be 
 careful to give the right position, diagonally parallel 
 to the sides of the screen, or we shall obtain the 
 opposite effea to what we desired, as fig. 19 shows 
 very instructively. If one is accustomed to work 
 with two stops it is of advantage to use for the 
 
 X 
 
 Fig. 24. 
 
 Fig. 25. 
 
 shadows the round stop, and for the lights a more 
 pointed one than illustrated in either figs. 26 or 17. 
 By this it is not meant that the round stop is 
 entirely to be rejected. For years we have worked 
 with it, and still use it, and we can yet accomplish 
 good work with it. 
 
 Influence ofthe Light, the Duration of 
 Exposure, and the Development.— The light 
 is so changeable that it is seldom or never possible 
 
6 4 
 
 HALF-TONE 
 
 in process studios to regulate it, and this is the 
 greatest difficulty to overcome. But there are ways 
 of meeting all inconveniences, and we must take 
 the light as we find it, with all its tricks and 
 caprices. If there is no electric light available it 
 will be best not to take a hard red-toned photograph 
 on a dull winter's day, or the result will be 
 pitiful. If we are, nevertheless, compelled to 
 work under such circumstances, 
 we must in this case choose the 
 shortest possible distance for 
 the screen, and prolong the 
 exposure even to one hour. 
 But it will never be possible to 
 obtain a really good result. 
 Strong diffused light or soft 
 sunlight gives the best results, 
 a strong illumination being 
 requisite. Only wash draw- 
 ings or grey photographs are 
 best suited for subdued light, the colour in 
 which they are executed being more actinic than 
 the red-brown of albumen prints. The darker the 
 shadows, the more light is wanted to clear them 
 up. If the light is decreased beyond a certain 
 limit, the action in the shadows stops altogether, 
 and even by very long exposure no light impres- 
 sion is obtained. Accordingly subdued light gives 
 more contrast than strong, and generally small 
 
 ♦ 
 
 Fig. 26. 
 
ON THE AMERICAN BASIS. 
 
 65 
 
 stops are necessary to bring about the result, 
 whilst with strong light larger stops can be used. 
 
 A further important influence on the modula- 
 tion of the dots is the duration of the exposure. 
 It is well known in ordinary photographic work 
 that prolonged exposures give soft negatives, and 
 over-exposure gives feeble negatives. The same, 
 as well as the opposite fact, that short exposures 
 give hard negatives, prevails, within certain 
 limits, in the half-tone process. But we must 
 keep in mind that other matters come into play 
 (such as the stop and distance) and that a half-tone 
 negative is never ready for use after developing and 
 fixing; it has to go through a series of further 
 operations before it is finished, and this changes 
 the appearance of the developed picture. It does 
 not follow that hardness is in all cases due to 
 under-exposure, because it may be that the action 
 of the light in the lighter tones has been counter- 
 acted by the use of a small stop or short distance 
 of the screen. The light thus acted more towards 
 the production of density than in causing the 
 spreading of the dots. A prolonged exposure may 
 absolutely give more contrast ; for instance, if the 
 development is interrupted at the right time and a 
 strong intensification given. In disregard of such 
 cases, every negative should be slightly over- 
 exposed and fully developed. The reason for this 
 is described later on in the chapter relating to the 
 
66 
 
 HALF-TONE 
 
 after-treatment in the negative. Strongly exposed 
 and under-developed negatives show great imper- 
 fection. There is a lack of strength and density in 
 the dots, because the whole of the silver acted upon 
 by light has not been reduced owing to the short- 
 ness of the development. The dots in the shadows 
 instead of being small, sharp, and dense, are thin, 
 scattered patches, with which nothing can be 
 done. The same want of sharpness prevails in the 
 lights, where the joining of the dots into lines is 
 lacking. 
 
 I have described at some length the principles 
 which are the basis of the work with the screen, 
 because I believe that with this knowledge a 
 quicker understanding of appearances which come 
 into evidence in the practical working of the half- 
 tone process will be attained, so that the 
 operator can meet all exigencies. The manipula- 
 tions of negative making I presume to be well 
 known, and I shall only describe those operations 
 which apply to work where the screen is used, 
 together with any new matters appertaining to 
 the subject. 
 
 The Practice of Half-tone Operating. 
 
 The photographer who undertakes to make a half- 
 tone negative must first examine his subject as to 
 its colour, strength, and detail, and take into con- 
 sideration the size of the reproduction, because by 
 reduction of size the relative clearness of the picture 
 
ON THE AMERICAN BASIS. 
 
 67 
 
 increases. From these facls, as well as upon the 
 conditions of the light, the charafter of negative 
 desired, and above all the distance of the screen, 
 he has to determine the diameter of the stop, and 
 the approximate duration of the exposure. After 
 this he fastens up the original on the copyboard in 
 such a manner that it is central to the axis of the 
 lens, so as to avoid inequalities of surface, 
 uneven lighting and reflections, etc., and focusses 
 sharply. On the last point greater care has to be 
 taken than with line originals. Any carelessness 
 in this respect gives trouble afterwards, and want 
 of sharpness is capable of making even the best of 
 negatives valueless. 
 
 Much care has to be bestowed on the cleaning 
 and polishing of the screen. Even though it may 
 seem trivial such matters must be learnt and 
 understood. It may happen that drops of silver 
 solution come on the surface, and these must be 
 removed with blotting paper. The polishing is 
 done in the same way as with negative glass, with 
 mixtures of alcohol, ammonia, and Vienna chalk, 
 or whiting, using clean and soft pads of Joseph 
 paper. The final polishing is given with a soft 
 leather, and the dust which the glass attrafts 
 (being elearic through the rubbing) is removed 
 with a soft brush. It is not out of place to observe 
 that a grain of sand or grit may entirely spoil the 
 screen ; therefore all materials for cleaning must 
 
68 
 
 HALF-TONE 
 
 be carefully preserved free from impurities. After 
 cleaning, the screen is fixed in the dark slide, and 
 covered with a preserving glass, which is only 
 removed when the sensitive plate is inserted for 
 exposure, and replaced afterwards. Anyone who 
 takes this precaution saves the screen very much, 
 as it has not to be so often cleaned ; it may even go 
 whole days without being taken out. 
 
 The distance of the screen from the sensitive 
 plate is subject to the 
 number of lines to the inch 
 and to the focus of the 
 lens. For a screen of 
 150 lines it will be about 
 T 3 gths of an inch, measured 
 from the cementing of the 
 screen. This makes about 
 Jgth to -^nds of an inch 
 between the surfaces, and 
 this separation may be 
 made with three strips of blotting board. For 
 shortening the exposure, or because larger stops 
 are used, we can place the screen a little closer to 
 the sensitive plate. 
 
 Polished plate glass is necessary for the nega- 
 tive making. On account of the numerous washings 
 which the collodion film has to undergo under a 
 strong rose tap (fig. 27) to save time, the glasses 
 are, after cleaning, coated with albumen. The 
 
ON THE AMERICAN BASIS. 
 
 6 9 
 
 white of an egg is well beaten in about two quarts 
 of water. This is poured twice over the plate 
 whilst wet, and is then dried. This substratum 
 makes the collodion film very resistant without 
 hindering the subsequent process of stripping the 
 film. Those who prefer to use polished plates 
 without substratum must not forget to border 
 them. 
 
 , A full exposure with a medium stop, about 
 //16 or//22 is given, and the plate developed. We 
 have now to determine whether the exposure on 
 the one hand, or the choice of the stop on the 
 other, was correct. The first is determined, if 
 after developing the plate, without considering the 
 lights, a small dot has commenced to form in the 
 shadows. But the correctness of the stop is 
 known, if in disregard of under-exposure of the 
 shadows, the high-lights in comparison with the 
 shadows, possess the necessary contrast. By 
 over-exposure the shadows are too clear, and the 
 lights are too intense ; whilst by under-exposure 
 the shadows are too transparent, but at the same 
 time the high-light dots are not sufficiently closed. 
 By experience it can soon be seen for certain 
 whether a negative is serviceable, after developing 
 and fixing (in a weak solution of cyanide of 
 potassium), and with this knowledge a great deal of 
 trouble is saved. From an original of medium 
 strength, the dense dot in the high-lights must 
 
Jo ■ 
 
 HALF-TONE 
 
 have the relative size of the dots in fig. 28, without 
 the dots being joined up and blended into each 
 other in the highest lights, and the general appear- 
 ance of all the dots will be wanting in sharpness. 
 Of possible intensifiers those only are of advantage 
 which build up most powerfully, such as lead ; mer- 
 cury is less satisfactory ; and the best is the copper 
 intensifier with the subsequent blackening with 
 silver, this intensifier being almost without excep- 
 tion in use. Equal parts of 12 per cent, sulphate 
 
 washing under a rose tap the plate is flowed or 
 bathed with a dilute solution of nitrate of silver, 
 about 5 per cent. The chief advantage of this 
 intensifier is the possibility of repeating it several 
 times on the same negative. If after the first 
 intensification the necessary strength and density 
 is not obtained, the operations can be repeated a 
 second, third, and even a fourth time. Thorough 
 washing must not be omitted, or a yellow veil will 
 be left after the further blackening with sulphide of 
 
 ••• 
 ••• 
 ••• 
 
 Fig. 28. 
 
 of copper solution, and 
 6 per cent, bromide of 
 potassium solution are 
 mixed together, and with 
 this the negative is 
 flowed over from wide- 
 mouthed bottles or 
 immersed in a dish. 
 After very careful 
 
ON THE AMERICAN BASIS. 
 
 71 
 
 ammonia. In case of a slight veil a clearing bath 
 of dilute hydrochloric acid is a remedy, and this 
 should generally be used after blackening with 
 sulphide of ammonium. If the yellow veil is con- 
 siderable a concentrated solution of cyanide of 
 potassium may be tried, but this must be done 
 carefully, as the density of the dots is also attacked 
 by it. Even if the choice of stop or exposure be 
 correct it is very seldom that a half-tone negative 
 is serviceable after one intensification. In no case 
 is the best quality of the negative obtained at the first 
 attempt. If we examine the shape of the dots with 
 a magnifying glass (one of three-fold power is the 
 best) we see that they have after the first intensifying 
 attained such a size that they overlap one another, 
 with moderately sharp edges, but when using the 
 round stop the density at the points where the dots 
 join is insufficient, and the shape of the transparent 
 openings is advantageous, being star - pointed. 
 Further the shadow dots are seldom brought out 
 well after one intensification ; they lack the neces- 
 sary density and sharpness. Therefore, in such 
 cases, we use the intensifier a second time, and 
 compare the result. The entire closing up of the 
 lights will now be attained and the transparent' 
 openings will have changed into a more square 
 shape with blunt edges, whilst the dots in the 
 shadows appear sharper and denser. The en- 
 larged negative illustrated in Supplement VI. may 
 
7 2 
 
 HALF-TONE 
 
 be turned to for an example of the right ap- 
 pearance. 
 
 But even in these ways the best negative ma)' 
 not be attained, it being difficult for the operator to 
 choose every time, not only the correct stop, but 
 to guess also accurately the duration of the ex- 
 posure so that the dots in the shadows possess the 
 necessary fineness. I had occasion to recommend 
 previously that as a rule a little over-exposure was 
 advantageous. In such cases we intensify once as 
 ordinarily with copper and silver, and after washing 
 well, pour over the negative a solution of wine- 
 yellow or wine-red iodine in water dissolved by the 
 addition of any iodide salt, for instance, iodide of 
 potassium (iodine dissolving alone in water only in 
 the proportion of i-6ooo) until the silver on the 
 surface of the negative is converted into iodide of 
 silver. It is useless, and needless, to pursue the 
 conversion until the whole picture is formed into 
 iodide of silver. As soon as there appears a green 
 sheen in the shadows, the treatment with iodine is 
 interrupted, the plate washed superficially, and a 
 very dilute solution of cyanide of potassium is 
 poured over in one even flow. According to the 
 strength of the solution a quicker or slower dis- 
 solving out of the iodide of silver takes place, and 
 it is easy to follow this by holding the negative 
 against a dark object, for instance the bottom of 
 the washing tank. Instead of using iodine and 
 
ON THE AMERICAN BASIS. 
 
 73 
 
 cyanide of potassium separately they can be mixed 
 beforehand, or instead of this a solution of ferrid- 
 cyanide of potassium and hypo may be used. The 
 ground of the negative becomes clear glass, the 
 dots sharpen, whilst all the granular deposit 
 attacked by the iodide varnishes, and in the 
 shadows a very sharp and small round dot is formed. 
 If thereby the lights, as is generally the case, 
 have cleared up too much, or the dots in the 
 shadows have lost in density, then the negative 
 should be re-intensified until the desired effect is 
 attained, and in this way will be obtained a perfect 
 negative. If the exposure was too much prolonged, 
 and consequently the shadows are filled up with a 
 thick black deposit, the reduction with iodide and 
 cyanide of potassium is difficult, because the 
 solutions have to be used strong, so that with the 
 reduction of size a reduction of density goes hand 
 in hand, the dots becoming transparent to such a 
 degree that the subsequent intensification does not 
 repair the damage. In this case it is better to 
 intensify and reduce alternately, whereby a gradual 
 increase of contrast takes place. Over-exposure 
 is easily recognisable by the time the picture takes 
 to make its appearance in development. I have 
 nothing new to add to my earlier explanation on 
 the shape and density of the dots. If the over- 
 exposure is very great we ultimately get a result 
 in which the dissecting influence of the screen 
 
74 
 
 HALF-TONE 
 
 altogether disappears and it gives the impression 
 of a negative produced without it. Under some 
 circumstances it is undoubtedly advisable to some- 
 what over-expose with a shorter development, so as 
 to force contrast in feeble originals. In this 
 manner the shadows are kept back, and can be 
 vigorously intensified without the necessity of 
 weakening the high-lights with strong reducers of 
 iodine and cyanide of potassium. If the stop 
 chosen has been unsuitable, i.e., if the negative taken 
 with it does not show the desired modulation, then 
 the exposure must be made with a larger or smaller 
 stop, either for the full time, or by changing for a 
 fraction of the time. The desirability of a further 
 exposure is best determined by comparing the last 
 finished negative with the first one. As we have 
 already explained large stops give the lights and 
 small stops the shadows. By strict observance of 
 this rule, and by considering that the duration of 
 exposure increases inversely as the square of the 
 relative diameter of the stop, we shall, supposing 
 the distance chosen at the outset was not too great, 
 arrive at the desired result. It is quite sufficient to 
 work with the stops only. The changing of the 
 distance is circumstantial and is for several reasons 
 risky, so that we need only decide to resort to it as 
 a last extremity. In making exposures with 
 changed stops two sizes from the customary set of 
 diaphragms should be chosen, with not too sudden 
 
ON THE AMERICAN BASIS. 
 
 75 
 
 a jump between their relative proportions, or the 
 different exposures will be exaggerated, and with 
 these successive exposures are made for a pro- 
 portionate time, that is to say, the exposure with 
 the larger stop must not be too short, or it will 
 not give enough strength, according to its value, 
 and the result in the finished negative will be 
 recognised by a zone of weaker density (fig. 29). 
 
 If it is necessary to take a hard original in a 
 bad light it is advisable, 
 according to what I have 
 already said, to use a very 
 small stop in order to keep 
 back the high-lights as 
 much as possible. It occurs 
 sometimes that owing to 
 over-exposure the clear 
 parts of the negative are 
 slightly veiled through 
 diffused light, and when we come to in- 
 tensify, the high-lights close up to a nearly 
 uniform blackness. It is impossible to reduce 
 strongly without weakening the feeble detail in the 
 shadows. In such case a dodge which renders 
 good service may be resorted to, viz., exposing for 
 a fraction of the time on a clean white sheet of 
 paper covering the original. The result is that the 
 negative is covered evenly with fine dots. Naturally 
 in this manner the shadows are a little lightened, 
 
76 
 
 HALF-TONE 
 
 but are not better detailed. The original must, 
 therefore, be exposed until the detail is at least 
 indicated by feeble dots. The exposure on the 
 paper is then resorted to, to strengthen the latter. 
 Glaring lights can be smoothed down in a similar 
 way whilst exposing, by moving about a piece of 
 black velvet fastened to a blackened wire. It often 
 occurs that large spaces, such as skies, on the 
 original are not clean and uniform or have too 
 much tone. . If the contour of the landscape is 
 rather simple a pattern of white paper may be cut 
 out, and held with a little movement (to prevent 
 sharp borders) over the space on the original which 
 has to be cleared up, exposing for a short time. 
 
 In the winter time, the veiling of the screen 
 with dampness is very vexatious. This occurs in 
 studios which are warmer than the dark-room. If 
 the latter is not warmed the only expedient will be 
 to warm the screen. The aclion of the damp veil 
 is easily distinguished on the negative by the 
 raggedness and unevenness of the dots. 
 
 A beginner will often find in the course of his 
 work that phenomena make their appearance for 
 which he cannot for the moment account nor prevent. 
 He should, as I have done, keep a diary, and note 
 in it carefully for every negative the circumstances 
 under which it was taken, the character of the 
 original, the light prevailing, the duration of ex- 
 posure, the size of stops used, the speed with 
 
ON THE AMERICAN BASIS. 
 
 77 
 
 which the picture developed, the nature and size of 
 dots before and after intensifying and reducing, and 
 the final result. This may seem circumstantial, 
 but I am assured from my own experience of this 
 method of work that it leads the beginner to a 
 knowledge of such phenomena, and how to secure 
 a successful result. One must not rely on memory, 
 the best forsakes one sometimes. If we have a 
 long series of notes at hand then a systematic com- 
 parison will give the reason for any difficulties. 
 Though the half-tone process is entirely a 
 mechanical one it is notwithstanding necessary to 
 avoid working like a machine, especially in the 
 photographic part. What else can be the cause of 
 such a large percentage of bad half-tone photo- 
 graphers ? A boy is apprenticed to a photo- 
 grapher, and sees the manipulation of the process, 
 which he learns, without thinking very deeply 
 about it, and without bothering his head much 
 over the why and wherefore of it. When he is 
 advanced later on to an independent position as 
 operator he knows nothing more than he has seen. 
 If the conditions and exterior circumstances under 
 which he works are the same, and the manner of 
 working which he has learnt a good one, he will 
 turn out a good photographer. But if it happens 
 that some trifling difficulty, ridiculous in itself, yet 
 quite new to him, comes in his way, then his whole 
 process is thrown out of gear, because he has not 
 
78 
 
 HALF-TONE 
 
 learned to think. He will seek in the silver bath 
 for the cause of streaks when actually the screen 
 was not cleanly polished, or complain that the 
 lens is not strong enough when the real cause 
 is that the screen distance was much too 
 great. However highly we may estimate the 
 practice, the theory is nevertheless the animating 
 spirit of it. 
 
 In the following I give a comprehensive 
 summary of the usual faults presented : — 
 
 Dots sharp and dense, but too Urge in the 
 shadows, the high-lights not closed : ovsr-exposure 
 and too small a stop (for the distance). 
 
 Dots sharp and dense, shadows correct, but 
 the high-lights not joined : exposure al. right, but 
 too small a stop (for the distance). 
 
 Dots sharp and dense, too large in tie shadows, 
 lights closed too much : stop correct but over- 
 exposed. 
 
 Shadows too transparent, with \ery feeble, 
 and partly lost dots, lights not closed : stop correct 
 but time of exposure too short. 
 
 Dots in the lights too square, lacking sharpness, 
 and without good joining, dots in the shadows very 
 grey and too much spread out : over-exposure and 
 under-development. 
 
 Dots in the high-lights too mtch closed, 
 shadows transparent : exposed with too large a 
 Stop (for the distance). 
 
ON THE AMERICAN BASIS. 
 
 79 
 
 Dots very indefinite, and hardly recognisable, 
 feeble in density, grey : very much over-exposed 
 (with large stop or too great a distance). 
 
 The transparent spaces in the high-lights 
 veiled : due to long exposure (generally in bad 
 light) or too large a stop. 
 
 No contrast, in spite of using large stop, par- 
 ticularly in bad light ; too great a distance, for 
 instance, with lenses of long focus. 
 
 No contrast, in spite of using small stop, 
 especially in good light: too much distance, i.e., 
 for lenses with short focus, or owing to strong 
 reduction. 
 
 Circular streaks : screen not cleanly polished. 
 
 Negative with uneven contrast : original not 
 evenly lighted, or screen not parallel to sensitive 
 plate. 
 
 Dots ragged and shapeless, looking like a 
 grained negative : screen veiled with dampness 
 (usually occurs in the winter). 
 
So 
 
 CHAPTER III. 
 
 STRIPPING AND REVERSING THE NEGATIVE. 
 
 In America only the direct printing process 
 on metal is used. The result of this is that 
 reversed negatives are required. Prisms are for 
 vaiious reasons not popular there. Apart from 
 their great cost it would necessitate an entirely 
 different arrangement of the copying stands and 
 putting the comfortable and cheap swinging camera 
 base out of use. A further reason is the rather 
 considerable increase of exposure, and the fact that 
 it is impossible to combine a number of negatives 
 on one plate for printing and etching. How would 
 it be possible, with the low prices now obtained, for 
 a process establishment to exist without obtaining 
 a number of prints on one plate ? Of course the 
 combination of large plates can only be used to a 
 limited extent, because of the difficulty of the half- 
 tone process, but after all there is not sufficient 
 reason for giving up the old plan of taking the 
 negatives direct and rt, versing them by means of a 
 
ON THE AMERICAN BASIS. 
 
 81 
 
 very short process. In large establishments a boy 
 is employed for this work, otherwise the photo- 
 grapher, printer, retoucher, or some one else finds 
 time in spare moments — the operator for instance 
 during an exposure — to do this little duty. 
 
 If the work is hurried, hardly more than a few 
 minutes is required for reversing. For quickly 
 drying of the negative either the direct flame of a 
 bunsen burner is used or the negatives are placed in 
 a drying box ; they may also be dried by being leaned 
 against a steam tube or by applying heat under the 
 plate rack, by means of a tube provided with small 
 bunsen burners. When the negative is dry and cool 
 it is coated with indiarubber solution. The way of 
 making this is to dissolve commercial indiarubber 
 cement in benzole until entirely liquid, and after 
 coating and drying it forms a very thin film which 
 can be rubbed away w^th the finger. Solid india- 
 rubber, which must not be vulcanised, should be dis- 
 solved by soaking it first in chloroform and allowing 
 it to stand until it swells a good deal and forms a 
 thick syrupy mass. This is diluted for use with 
 benzole, the solution being shaken well until all is 
 dissolved, and then filtered through cotton wool. 
 The solution will filter quickly enough if no more 
 solid portions are present. The benzole evaporates 
 from the film on the negative in a short time, and 
 may be hastened by holding the plate over a flame 
 for a few moments. When cool it is coated with 
 
 F 
 
82 
 
 HALF-TONE 
 
 leather-collodion, i.e., two per cent, plain collodion 
 with a little castor oil added. An excess of alcohol 
 in the collodion is of advantage by increasing the 
 flexibility of the film. The addition of oil must not 
 be carried too far, as the pyroxylin being only two 
 per cent, strength the film will be too much 
 softened and will cause a flattening out in the 
 printing frame. Too little oil, on the other hand, 
 makes the film hard and wrinkled and prevents 
 strong adherence to the glass. The following 
 recipe has been well tried : — 
 
 Alcohol 65 parts. 
 
 Ether 35 
 
 Pyroxylin 2 
 
 Castor oil 1 to i£ 
 
 In order to secure even thickness of the film, and 
 because where there is no indiarubber covering, the 
 negative film is dissolved by, the collodion, and the 
 picture soiled by the silver running over, it is better 
 after the second coating to pour off from the 
 opposite corner. To ensure the easy stripping of 
 the film it must be perfectly dry before each 
 coating. Never pour the solution on to the warm 
 negative, or air bubbles will be the result, rendering 
 the negative under some circumstances, useless. If 
 the leather collodion tears up raggedly it is too 
 thick and must be diluted with equal parts of ether 
 and alcohol. If thicker films are preferred leather 
 collodion can be poured on a second time. When 
 
ON THE AMERICAN BASIS. 
 
 83 
 
 this film is dry (to hasten drying heat can be 
 applied), a cut is made in the margin of the picture 
 and the plate immersed in watei to which has been 
 added acetic or sulphuric acid. According to the 
 strength of albumen solution with which the nega- 
 tive has been coated at the outset, the film loosens 
 either immediately or after a short time so that it 
 is possible to take it with the fingers and lift it off. 
 It is then turned and laid on a wetted piece of plate 
 glass. This operation is with a little practice and 
 care, quite certain without any danger, and even 
 with the largest sizes the loss of a negative except 
 through carelessness is impossible. The film is 
 then squeegeed to the glass with a very light rubber 
 squeegee of the thickness of a cardboard, or with 
 strips of copper-plate printing paper, scraping from 
 the centre to the edges of the glass, any remain- 
 ing drops of water being removed with blotting 
 paper. If contrary to expectation a loosening at 
 the edges occurs it is sufficient to apply a touch of 
 gum solution to them. When the film is at last 
 dry by warming for a few moments, the process of 
 reversing is accomplished. If, as is generally the 
 case, a fine line round the picture is desired, a cut 
 can be made in the desired place before stripping 
 the negative. The margin will print solid black 
 and the engraver can cut the thickness of the line 
 as desired. It is more certain if the negative after 
 stripping (for which operation it is of advantage to 
 
*4 
 
 HALF-TONE 
 
 leave a margin to take hold of the film by) is cut 
 sharply along the limits of the picture, and the 
 useless strips removed by damping them slightly. 
 A third way is to make the margin line with a 
 pointed piece of wood, on the dry uncoated negative, 
 in such a manner that only the superficial deposit 
 on the film is removed, without injuring the 
 supporting collodion. 
 
 The collodion films offer a further advantage 
 which is worth noting. It often happens that half- 
 tones are wanted with borders of line work. 
 Nothing is easier than cutting the two negatives so 
 as to fit the half-tone into the line negative, when 
 both may be etched together. A particularly 
 experienced hand is necessary to combine etched 
 plates in this manner, and even when great care is 
 exercised, to obtain the exact type height of all 
 parts it requires increased attention on the part of 
 the printer to equalize by means of overlays the 
 unavoidable defects. 
 
 The Direct Printing of Negative Films 
 on the Metal. — In conjunction with the stripping 
 and turning of the negatives, I shall speak directly 
 on how to print negatives on the metal without a 
 frame. This method, especially for line negatives, 
 in certain cases has great advantages and is also 
 applicable for half tones. If for instance, an 
 original has to be reproduced of a size exceeding 
 the capacity of the lens and printing frame, it had 
 
ON THE AMERICAN BASIS. 
 
 85 
 
 formerly to be photographed, printed, and etched 
 in several parts ; but the following method will be 
 found better, and will lead to a direct result whilst 
 avoiding double work. For coating the different 
 parts to be combined, more concentrated solutions 
 of indiarubber and collodion are used or, after the 
 drying, the plate is coated a second time and 
 allowed to dry in a horizontal position so as to 
 obtain thicker and more resisting films. The 
 negatives are cut to match, and stripped ; and can 
 then (the coated side upwards) be laid together on 
 a glass plate. Another coating with indiarubber 
 and collodion is given and the whole stripped as 
 an ordinary negative. The single pieces may, 
 however, be joined together and used at once 
 without stripping for printing on the metal. It is a 
 condition of success that the films should be perfectly 
 dry. The best way is to put them between layers 
 of blotting-paper and dry with heat. Meanwhile a 
 zinc plate has been prepared with albumen or 
 enamel solution as described in the following 
 chapter. If the plate is dry it may be flowed over 
 with spirit of turpentine free from water, and the 
 negative films, also dipped into the turpentine, 
 are then laid on the plate and squeegeed with a 
 flat, light, felt squeegee. After exposure the plate 
 is brought again into the printing-room and the 
 films taken off. When the turpentine has 
 evaporated over a stove, the further manipulations 
 
86 
 
 HALF-TONE 
 
 are taken in hand in the manner described later on. 
 Instead of turpentine some use castor oil, a few- 
 drops of which is distributed with a little gelatine 
 roller. Paraffin is also used as a cement. In any 
 case no trace of water must come in contact with 
 the prepared plate — even atmospheric dampness 
 may harm it ; the films will not come off and are 
 irreparably lost. If printed on asphalt the process 
 is much simplified because the films are put down 
 wet as they come from the glass and can be taken 
 off under water. 
 
«7 
 
 CHAPTER IV. 
 
 THE PRINTING PROCESS. 
 
 When the negative is finished, reversed, and 
 dried, as described in the preceding chapters, it 
 comes into the hands of the printer. The latter has 
 to make on a flat metal plate a print from it 
 adapted to resist the acid solution, by deepening 
 the bare parts of the metal. For this purpose a 
 planed zinc, copper, or brass plate is coated with a 
 solution of albumen and chromate salt, exposed to 
 light under the negative, coated with a fatty ink, 
 and the parts not acted upon by the light, washed 
 away with water. We then secure from a negative 
 a positive on metal, which after deepening of the 
 uncovered parts serves as a printing surface for the 
 press. The metal may be coated with other 
 substances, made sensitive to light, such as gum 
 arabic, fish glue, or thicker solutions of albumen, 
 and developed without rolling up, with fatty ink. 
 Printing with asphalt is mostly out of use, as is 
 also the transfer printing process. Both require too 
 
88 
 
 HALF- ['ONE 
 
 much time or a too complicated apparatus. All pro- 
 cesses for letterpress reproductions must possess 
 simplicity and speed. A process may give better 
 results, but as soon as it exceeds the shortest time 
 attained by other processes it is abandoned, because 
 time is money. It is for this reason that the 
 ingenious swelling process has been entirely dis- 
 carded, and the gelatine wash-out process is on its 
 death-bed, whilst the carbon process offers no new 
 advantages in practice. Of all methods, business 
 has adopted the diredt printing albumen process 
 as the shortest, the cheapest, and the easiest to 
 handle. It needs hardly any arrangements worthy 
 of the name, and its results are amongst the best, 
 though undoubtedly surpassed for beauty in the 
 half-tone process by the diredt printing enamel 
 preparations. 
 
 The Zinc. — Of the materials coming under 
 consideration, zinc and its handling deserves first 
 attention. If the zinc is bought in raw rolled 
 sheets, the plate polisher, employed in every large 
 firm, chooses first the best side of the zinc by 
 etching a corner of both sides in a weak (about 
 five per cent.) nitric acid solution ; the zinc is 
 liquid at the commencement of rolling it into sheets, 
 it bubbles, and particles of grit mount to the surface. 
 Thus every sheet has two different surfaces of 
 which the better one is easily ascertained by 
 applying the etching brush. After etching, pure 
 
ON THE AMERICAN BASIS. 
 
 8 9 
 
 zinc should have a silvery lustre. A slight per- 
 centage of lead is of no consequence, but an excess 
 causes the plate to become rough and to etch 
 unevenly, because the nitric acid dissolves the lead 
 much more slowly than the zinc. The presence of 
 lead is to be distinguished by its brilliancy and 
 the colour of the metal. For the same reason carbon, 
 next to lead, disturbs the uniformity of the etching. 
 If little cracks and holes are present, and the metal 
 blisters in different places, or shows a streaky 
 structure, there has been some fault in rolling the 
 sheets, and this makes the metal unfit for etching 
 purposes. The acid finds its way through the 
 porous surface, and undercuts the fine dots and 
 lines. In general, Belgian zinc is regarded as 
 the best. It is possible that an inferior quality is 
 exported to America, or the etchers there do not 
 understand the advantages of it. In short it is not 
 much liked, because of its slow etching and its dark 
 colour. The superiority is left to the native pro- 
 duct. The grinding and polishing of the zinc plates 
 is troublesome work, especially if the latter are in- 
 tended for half-tone purposes. The best plan is to 
 etch the plates first with a diluted nitric acid solution, 
 until they are cleaned of oxide, and then to grind 
 them down wet with a piece of finest pumice stone 
 in the direction in which they have been rolled into 
 sheets. If large depressions are present which cannot 
 be levelled by grinding, mark them with a marking 
 
HALF-TON E 
 
 gauge, punch them out and grind again. Small but 
 deep holes or cracks which cannot be punched out 
 are covered with shellac or asphalt varnish, and by 
 further etching the plate elevations are created 
 
 Fig- 30. Fig. 31. 
 
 round the holes, so that the latter can be removed 
 by treating the plate again with the stone. The 
 stone polished plates are still too rough for etching 
 purposes, and to remove this, rotten-stone, and 
 afterwards charcoal or emery powder of increasing 
 
ON THE AMERICAN BASIS. 
 
 9 1 
 
 fineness, is used. It is to be remembered that the 
 polishing must be done always in the same direction. 
 Instead of etching the plates a scraper (fig. 30) can 
 be used, but the handling of this tool requires 
 practice and skill. All comparatively large estab- 
 lishments in New York run a polishing machine, 
 
 Fig. 32. 
 
 which executes the polishing work far better and 
 more quickly. This machine is in principle a very 
 quick rotating axle, on the ends of which are two 
 discs composed of circular pieces of linen or flannel 
 screwed together in the middle (see fig. 31). 
 Through the centrifugal force the separate layers 
 stretch out and form a complete, hard but elastic 
 
9 2 
 
 HALF-TONE 
 
 wheel which with the assistance of a polishing 
 medium composed of tallow and emery powder or 
 English rouge, polishes admirably. Instead of linen 
 or flannel, rhinoceros leather pads are used with 
 advantage. The cutting up of the plates to the 
 desired sizes is done with the zinc cutter, which is 
 a piece of steel bent into an angle, or with a circular 
 saw (fig. 32). When the burr of the edges has 
 been filed down the plate is delivered to the 
 printing-room where it receives the last operations 
 before printing. 
 
 These consist of freeing the zinc from any 
 greasiness by washing it with a solution of soda or 
 potash, or by mechanical rubbing with a tuft of 
 damp cotton wool dipped in the finest emery 
 powder until the water is not repelled by the plate. 
 Many workers hold that a highly polished plate is 
 undesirable, preferring a matted one. For this 
 purpose a solution of nitric acid and alum is poured 
 over the plate, or it is put into a bath of this 
 solution, and left to its aclion for a short time until 
 the polished surface has taken an evenly dull matt. 
 In this state the plate is ready to be coated with 
 a sensitive solution. If this is not done directly, 
 care must be taken that the plate is quickly dried 
 or kept under water. Copper is also treated in 
 the same manner as zinc. Because of its hardness 
 and the difficulty in working it, it is generally bought 
 highly polished or at least evenly ground down. 
 
ON THE AMERICAN BASIS. 93 
 
 Materials for Printing. — For the plant in 
 the printing process in the first instance, a whirler 
 is necessary. This is for the purpose of dis- 
 
 Fig. 33- 
 
 tributing the solution evenly on the plate, and for 
 removing the excess. The most simple construc- 
 tion consists of two small flat wooden legs of about 
 16 to 28 inches long, which are connected at one 
 
94 
 
 HALF-TONE 
 
 end with a hinge or strip of leather. Near to 
 the other end on the inside are cut two notches, in 
 which the plate rests, clamped between the two 
 legs. An indiarubber band round the legs holds 
 the plate whilst in rotation. The whole arrange- 
 ment hangs on a short piece of string or wire, and 
 
 Fig. 34. 
 
 by turning the latter it can be set into the quick 
 rotation desired (fig. 33). Simple and unpretending 
 as this construction is, it renders good service. It 
 is certainly a little awkward to work with ; never- 
 theless, printers who have used it prefer it to 
 many other more elaborate kinds, as it gives the 
 
ON THE AMERICAN BASIS. 
 
 95 
 
 cleanest and most even films. In other construc- 
 tions the turning movement is operated by means 
 of a handle or cog wheel. They are built partly of 
 wood and partly of iron, and are more or less 
 practical. To prevent splashing of the solution, 
 and also to keep the dust out, the disc or cross is 
 surrounded by a flat case with cover. The disc is 
 provided with numerous holes, in which four short 
 pieces of wood are fixed, between which the 
 
 Fig. 35- 
 
 rotating plate is fastened, or the latter is fixed as 
 in illustration (fig. 34), between two or four 
 moveable screws. The clumsy wooden disc can 
 be omitted, and an iron cross can be put in its 
 place. The kind illustrated by fig. 34, in the 
 form of an interrogation mark, is especially to 
 be recommended. The axle with the cross can 
 be taken off. The plate is fastened with the four 
 screws, then prepared and whirled film downward 
 to avoid the dust. At the same time the plate can 
 
96 
 
 HALF-TONE 
 
 be dried by means of a gas burner placed under it. 
 In the same manner as with the film downward, the 
 plate can be whirled film upwards by fixing the 
 axle from the top. By this means the unmounting 
 of the cross after every coating is avoided, whilst 
 the case with a cover prevents the entrance of the 
 dust. I have replaced the cross with its flat 
 divided arms, by solid square iron rods, and con- 
 
 Fig. 36. 
 
 strutted the catches with turned up edges in such a 
 manner that they are able to keep the plates down 
 (fig- 35)- The whole machine stands under a 
 table, and is fastened with screws to a strong 
 board. The cross only rises over the table, and is 
 protected against dust by a flat case, which can be 
 opened entirely or only partly in the middle. The 
 drying of the plate is done in this case over gas or 
 on a hot stone, which receives its heat from a gas 
 
ON THE AMERICAN BASIS. 
 
 97 
 
9 8 
 
 HALF-TONE 
 
 stove or steam tube. A further arrangement for 
 whirling and drying at the same time, is shown in 
 fig. 36. All these constructions are good so long 
 as they fulfil their purpose, which is to distribute 
 evenly the solution which has been poured on a 
 flat surface. 
 
 Besides the whirler with the necessary arrange- 
 ment for drying, the printing-room requires a water 
 sink for washing the plates, and a flat tray for 
 developing. This may be a wooden tray, zinc 
 lined, provided with cover and tap, a couple of ink 
 rollers and ink slab (a fixed plate of glass) and a 
 number of printing frames, the size of which are in 
 comparison to the size of the combined negatives, 
 and is in general not smaller than 11 x 14 inches, 
 and not larger than 18x22 inches, the plate glass 
 being not able to support the weight of the screws 
 and wedges in larger sizes. The old kind of 
 printing frame is sufficiently known to be omitted 
 here ; instead of wedges wooden screws were used, 
 which to the number of 9 to 12 for n x 14, or 16 
 to 20 for 14 x 17 frames, allowed a better distribu- 
 tion of the pressure (see illustrations, figs. 37, 38, 
 and 39). To avoid the handling of so many screws 
 the number of these has been reduced to two or 
 one, and the others compensated for by a construc- 
 tion which is very similar to a copying press. The 
 back has been constructed from a flat iron plate 
 with sufficient resistance to distribute the pressure 
 
ON THE AMERICAN BASIS. 
 
 99 
 
IOO 
 
 HALF-TONE 
 
 of one or two screws over the whole surface. The 
 pressure of wedges is entirely sufficient to press 
 zinc plates of ordinary thickness perfectly against 
 the negative. It is more difficult to obtain suffi- 
 cient contact with copper plates, and therefore the 
 massive screw frames have been introduced. In 
 proportion to the high pressure the thickness of 
 
 Fig. 39- 
 
 the printing frame glasses has been increased, and 
 plates three-quarters to one inch thickness are 
 generally used. Figs. 40 and 41 show a frame 
 with two screws. After exposure of the sensitive 
 plate it is covered with a thin film of greasy ink — 
 i.e., transfer ink, or a special preparation is used 
 for this purpose. The ink must be easy to dis- 
 tribute and sufficiently greasy to develop with 
 
ON THE AMERICAN BASIS. 
 
 IOI 
 
102 
 
 HALF-TONE 
 
 sharp edges and without smearing. For many 
 years I have made my rolling-up ink myself, 
 
 according to the following recipe, and have the 
 pleasure of knowing that both printers and etchers 
 are very well satisfied with this for its easily 
 
ON THE AMERICAN BASIS. 
 
 developing properties and acid-resisting qualities : — 
 
 Asphalt i part. 
 
 Resin 1 
 
 Wax i .. 
 
 Mutton tallow i 
 
 Letterpress ink 9 parts. 
 
 Venice Turpentine i to ,, 
 
 These are dissolved in the order given, and thinned 
 with turpentine to the consistence of soft soap. 
 Two very soft leather or compo rollers serve for 
 the even distribution of the ink. Besides the 
 greasy ink, solutions of asphalt may be used 
 instead for coating the printed plates, but, so far 
 as I know, they are not much in vogue. 
 
 The preparation of the albumen solution is 
 very simple, and consists of white of egg, chromate 
 salt and water, with or without the addition of 
 ammonium or alcohol. The white of a fresh egg 
 is beaten to froth, diluted with 7 to 8 ozs. water, 
 with about 15 grains bichromate of ammonia 
 powdered in a mortar and added; the whole is 
 filtered through cotton wool once or more until 
 entirely clear, avoiding the formation of air 
 bubbles. Instead of ammonium bichromate, 1 oz. 
 of a saturated solution of potassium bichromate 
 may be used. A few drops of liquor ammonia 
 makes the solution keep better. By increasing the 
 amount of the chromate salt, and also by diluting 
 with water, the sensitiveness of the film increases 
 so much that after a few seconds exposure in sun- 
 
HALF-TONE 
 
 light a picture is obtained ready for development. 
 But nothing is to be gained by such extremely 
 sensitive preparations, except in case of bad 
 light, as very dense negatives are required. The 
 chance of the success of the print, on account of the 
 probability of easily over or under-exposing, are 
 much less, and besides this the excessive thinness, 
 of the film renders the development more difficult. 
 An excess of the chromate salt makes the film 
 porous. The solutions will keep for a certain 
 time ; according to an experiment I have made, an 
 albumen solution of my own make, six months old, 
 gave a print which on development was not to be 
 distinguished from a fresh one. The solution is 
 made in the following manner : white of egg is 
 beaten to a froth and allowed to stand until clear. 
 Meanwhile, a larger quantity of the following 
 solution is made : — 
 
 Liquor ammonia 12 parts. 
 
 Alcohol r g 
 
 Ammonium bichromate 6 
 
 A part of the albumen solution is mixed with 
 an equal part of the chromate solution, diluted with 
 two parts of water, and filtered through cotton 
 wool. The best way is to tie over the pouring 
 bottle (a tall wide-mouthed one is preferred) a linen 
 or coarse bolting cloth, and to thus obtain whilst 
 pouring a second filtration. As a matter of course, 
 
ON THE AMERICAN BASIS. 
 
 in this case we have to provide for the necessary 
 circulation of air by introducing a tube in the neck 
 of the bottle. Instead of fresh eggs the commercial 
 egg albumen may be used with equal success. It 
 must be dissolved in the same quantity of water as 
 is contained in the white of egg, viz., 14 parts 
 albumen in 100 parts of water. Possibly the 
 commercial albumen may not be pure, and at any 
 rate its sensitiveness is about half that of fresh 
 white of egg. Taking into consideration this cir- 
 cumstance, the solution should be diluted further, 
 according to the following formula, and thereby the 
 cost of making the solution is very much less. 
 Solution i. 
 
 Dried albumen 14 parts. 
 
 Water 100 
 
 Solution 2. 
 
 Alcohol 18 parts. 
 
 Ammonium bichromate 6 
 
 Liq. ammonia 12 
 
 Water 100 » 
 
 The solutions are mixed together, diluted with 400 
 parts water and filtered. The dissolving of the 
 albumen is assisted by adding liquor ammonia to a 
 reasonable extent. The chromated albumen is not 
 very sensitive to light, and it is not necessary to 
 fear daylight affeaing it much, nor is it necessary 
 to be over-careful in making the printing-room into 
 a dark-room. If it" should happen that the day- 
 light has an influence on the plates, we can at all 
 
io6 
 
 HALF-TONE 
 
 events pour over the window of the printing-room 
 a well filtered and very thin yellow solution of 
 asphalt in turpentine. Any further precautions are 
 superfluous. 
 
 To complete the arrangements of the copying 
 room an electric arc lamp is required, so as not to 
 depend entirely on the fitfulness of sunlight. It is 
 not necessary to have a lamp of 16,000 candle 
 power as is used by the Moss Engraving Company, 
 of New York. With one of 4000 candle power, 
 provided with a reflector for the concentration of 
 the rays, we have a source of light which repre- 
 sents for small sized plates, with the frame at a 
 convenient distance, more than half the strength of 
 sunlight. 
 
 Coating the Plate with Albumen.— When 
 the solution is ready for use, the zinc plate clean, 
 the whirler freed from dust by means of a damp 
 rag, and the drying stove at the right heat, the 
 coating of the plates can be proceeded with. The 
 plate is well washed under the water tap, drained, 
 laid flat on the left hand, and a sufficient quantity 
 of the solution poured on it a little to the left side. 
 When the opposite left-hand corner is covered, 
 allow the solution to flow to the right-hand side 
 driving the water before it as the excess flows off 
 at the lowest corner into the sink. The plate is 
 inclined back so that the solution flows again to 
 the centre, then fixed on the whirler, and quickly 
 
ON THE AMERICAN BASIS. IO7 
 
 rotated. The speed is difficult to determine, and is 
 mainly subjeft to the construction of the whirler, 
 but it should be a rule to whirl always for the 
 same time, and with the same speed. In this 
 way films will be obtained of equal thickness and 
 sensitiveness. Whirling either too quickly or too 
 slowly results in an uneven distribution of the 
 solution. If the plate is not dried on the whirler, 
 it is now taken off and dried over a gas-stove or 
 heating-plate. It is not necessary to be very 
 careful in warming the plate. So long as the 
 metal can be borne on the hand there is no danger 
 that insolubility will occur through coagulation of 
 the albumen. In damp or cold weather it is of 
 advantage to warm the negative to prevent moisture 
 forming between the negative and zinc, which would 
 stick together. The best way of bringing them 
 together is to lay the zinc across a corner of the 
 table, and to place the negative, film downwards, 
 upon it in the desired position. The two are then 
 pressed together with both thumbs and fingers, 
 lifted and turned over quickly. All uncleanliness of 
 the glass side of the negative and the glass of the 
 printing frame must be scrupulously avoided, and 
 it must be remembered that a most insignificant 
 grain of sand or grit is sufficient to smash the glass 
 plates under the high pressure to which they are 
 subjected. The screws must be tightened by com- 
 mencing at the corners, and evenly distributing the 
 
io8 
 
 HALF-TONE 
 
 pressure over the whole plate ; in the same way in 
 opening the frame one must be careful that the 
 whole pressure is not allowed to rest on one 
 screw. 
 
 The time of exposure depends in the first place 
 on the light, the composition of the printing 
 solution, and the density of the negative. In 
 average good sunlight in the summer, it is from one 
 to two minutes for line work, and two to three 
 minutes for half-tone work." The more vertically 
 the rays fall on the frame, the more sharply the 
 dots develop, and by using a tube, blackened inside 
 over the printing frame, the best results are 
 attained, yet the difference is so infinitesimally 
 small in direct printing on metal that it is hardly of 
 any advantage to use it. The case is different 
 when during a long exposure, the light has to pierce 
 a thick gelatine film. For the wash-out and swelled 
 gelatine processes it has been customary to use 
 printing frames with a series of long square tubes 
 extending in front. The frames were also arranged 
 on a turntable so that they could be directed 
 towards the sun irrespective of its position. By 
 this arrangement lateral action was avoided, the 
 lines were not so much thickened, and extremely 
 sharp dots in the shadows were easily developed. 
 In the albumen films relief is out of the question, 
 and the dots are far less subject to spreading, hence 
 the rare use of tubes. 
 
ON THE AMERICAN BASIS. IOO, 
 
 After exposure the plate is taken out of the 
 frame and the film coated with transfer ink. The 
 ink is evenly distributed on the ink slab with a 
 roller and the plate well warmed, then rolled until 
 it has taken a grey coating. With a single roller 
 an even film is seldom obtained, hence a second 
 rolling is given, - as soon as enough ink is on the 
 plate, with a clean soft leather, velvet, or compo. 
 roller. The plate if desired can be warmed again 
 and rolled over in different directions. There is no 
 need to be afraid that the albumen film will be 
 injured. I have never had a single case where 
 damage has been caused by even the heaviest 
 rolling, except when the roller was gritty or 
 had fragments of the metal sticking to it. A 
 light grey, shiny coating is just right. If too 
 much ink has been put on the plate, it can be 
 removed by sprinkling with turpentine, and rolling 
 again, or the second roller is cleaned with turpen- 
 tine, the plate once more heated, and the excess of 
 ink removed by a quick rolling. The development 
 can be commenced at once. If the exposure has 
 been correct the albumen unacted on by light dis- 
 solves directly it comes in contact with the water, 
 and it needs only a slight circular rubbing with a 
 tuft of cotton under water to remove the ink which 
 has lost its albumen support. If the ink smears 
 through rubbing too strongly in the shadows too 
 much has been applied, or it is too greasy, and has 
 
no 
 
 HALF-TONE 
 
 then to be remedied by drying in the air. If on 
 the contrary it is difficult to rub off the ink it has 
 been too stiff. In this case rolling up on tie slab 
 with a few drops of turpentine or oil of lavender is 
 useful. If the plate develops in some parts with 
 difficulty whilst the other parts are all right, the 
 cause may be want of contact in the printing frame or 
 that the part in question was overheated. A slight 
 over-exposure can be corrected in most cases by 
 developing in water containing ammonia or bichro- 
 mate. Add to a glass of water a few drops of 
 ammonia until the smell is distinctly discernible, 
 and develop with this solution. Too much 
 ammonia will dissolve the ink. If the negative 
 was all right the making of a perfect print is very 
 easy. The picture develops plainly and surely, and 
 the finest dots in the shadows can be opened with 
 the same ease as the lights. On the other hand if 
 the negative is faulty, and with the best operator it 
 is not always possible to make a perfect negative, 
 simply because there is no time, owing to the 
 urgency of the work, to make a second or third 
 exposure, the printer has to make up the defects 
 as far as lies in his power. A very frequent 
 case is that the dots in the shadows have 
 insufficient density ; here it is best to make the 
 exposure as short as possible, and use very little ink. 
 On the other hand, if the shadows are too open, or 
 the high-lights too closed, the exposure should be 
 
ON THE AMERICAN BASIS. 
 
 Ill 
 
 increased and more ink applied in the rolling up. 
 Besides this we must take into consideration that 
 as a rule clear sunlight gives softer, and diffused light 
 harder prints. When the plate is developed rinse 
 it with clean water, and dry at once with a soft leather 
 pad, or with heat, to avoid water markings. The 
 plate is now ready to pass from the hands of the 
 printer to the retoucher. It will be seen that the 
 albumen process is so simple, certain, and quick as 
 to enable in urgent cases a print to be made in 
 less than fifteen minutes from commencing the 
 coating. 
 
 The Enamel Process. — Now I come to a 
 process which in an incredibly short time — it is 
 hardly more than three years since the appearance 
 of the first vague reports of it — has been introduced 
 into all the engraving establishments in the United 
 States, and has very quickly won the hearts of all 
 practical men. I mean the enamel process on 
 copper. A long time before its introduction, here 
 and there etching was done on copper, and 
 generally with good results. In this matter the 
 Moss Engraving Company was in advance of all 
 others in America. Printing on copper does not 
 differ from zinc, and it is not necessary to add a 
 single word to the description of the process already 
 given. The advantages of copper over zinc were 
 soon recognised, because of its purity, close 
 structure, polishing quality, its durability in the 
 
112 
 
 HALF-TONE 
 
 press, and the property of giving smoother and 
 softer proofs than zinc. In perchloride of iron, too, 
 we have an excellent medium for etching, and thus 
 in all ways attention has been directed to copper 
 blocks. They very soon gave a better quality work 
 and were better paid for. But the highest step in 
 perfection of copper etching was attained when in 
 the enamel preparations — the originator of which, 
 so far as I know, was Ives, of Philadelphia, or after 
 others, Levy, of Philadelphia — two new acquisitions 
 to the existing qualities were obtained, viz., a 
 durable etching ground, and a better printing 
 surface for the press. Since the process became 
 known it has been re-invented many times, new 
 formulae have been worked out, and have been 
 carefully guarded by the initiated. Owing to the 
 ease of etching such prints on copper, half-tone 
 etchers have sprung up in America like mushrooms 
 from the ground. Those who were not much good 
 for anything else called themselves copper etchers, 
 and were engaged on good wages. The continual 
 changing of the workers from one establishment to 
 another soon put an end to the last traces of the 
 secret, and to-day the enamel process has almost 
 entirely supplanted the albumen process for half- 
 tone in America. In a way that can be seen at a 
 glance, I give on the opposite page the composition 
 of a series of preparations, some tried by myself 
 and others obtained from capable printers, who 
 
ON THE AMERICAN BASIS. II3 
 
 have worked and become acquainted with their 
 qualities. 
 
 
 I. 
 
 II. 
 
 III. 
 
 IV. 
 
 V. 
 
 VI. 
 
 VII. 
 
 Water 
 
 7 oz 
 
 7 oz 
 
 7 oz 
 
 7 oz 
 
 7 oz 
 
 7 oz 
 
 7 oz 
 
 Fish glue .... 
 
 2 oz 
 
 
 
 44 oz 
 
 i4 oz 
 
 34 oz 
 
 
 Gum arabic . . 
 
 
 1 oz 
 
 
 
 
 
 4 oz 
 
 Albumen .... 
 
 
 
 4 oz 
 
 44 oz 
 
 
 
 2 OZ 
 
 Sugar 
 
 
 
 
 
 
 ioogrs 
 
 
 Ammonium 
 
 
 
 
 
 
 
 
 bichromate. . 
 
 4 8grs 
 
 ioogrs 
 
 i20grs 
 
 90 grs 
 
 30 grs 
 
 200 grs 
 
 i20grs 
 
 Chromic acid . 
 
 
 
 12 grs 
 
 3 grs 
 
 15 grs 
 
 
 
 Liq. ammonia . 
 
 idr 
 
 some 
 
 
 
 17 mms 
 
 
 some 
 
 Alcohol 
 
 1 dr 
 
 
 
 
 
 
 
 Chrome alum . 
 
 15 grs 
 
 
 
 
 
 
 
 (In translating the above table from metric weights and measures, 
 fractional calculations have been omitted, but the figures given will be 
 found near enough for all practical purposes.— Trans.) 
 
 We see from the above what a wide difference 
 exists in the concentration of the solutions, and the 
 chromate contained in them. Consequently the 
 adtion, according to their composition, is somewhat 
 different. The recipes I. and II. are excellent in 
 every way, and have been " tried in the fire," being 
 worked under my supervision for a long time. 
 
 The principle of all enamel processes is that a 
 metal plate is coated with a sensitive solution, 
 exposed under the negative, and developed with 
 water, the film being finally hardened by means of 
 heat (enamelled), and thus rendered durable 
 against the action of the acid. To illustrate the 
 necessary manipulation I choose the gum prepara- 
 tion (Formula II.) The work with it requires 
 
 H 
 
ii4 
 
 HALF-TONE 
 
 more skill than with the glue preparation, and for 
 that reason, therefore, it seems more fitting to de- 
 scribe it and direct attention to all possible troubles, 
 accustoming the operator to scrupulous exactitude. 
 The entire enamel process is more delicate than 
 the albumen process, and the careless work which 
 is allowable with the latter, generally leads to want 
 of success with the former process. The claims 
 on the photographer and also on the printer are 
 increased. 
 
 The easiest way is to buy the gum arabic 
 powdered, the powder being quickly dissolved. 
 Weigh out the desired quantity, put it in a good 
 sized mortar ; add as much alcohol* as will evenly 
 damp the powder, and whilst uninterruptedly 
 grinding with the pestle, pour in gradually half 
 the necessary quantity of water, until a thick liquid 
 is obtained. If the work is done well the trouble- 
 some lumps formed by the gum are avoided, and the 
 solution is effected in a few minutes. After this 
 the second half of the water, in which the chrome 
 salt has been dissolved, is added. A few minims 
 of ammonia are added and the whole poured into a 
 boiling flask, which is put into a water bath and 
 warmed until the contents are entirely dissolved. 
 After the solution is cold it is tested up to n° 
 with a hydrometer for heavy liquids, and filtered 
 
 *The Author does not give alcohol in formula II. in 
 preceding table; probably an inadvertent omission. — Trans. 
 
ON THE AMERICAN BASIS. 115 
 
 through damp cotton wool. The preparation 
 keeps for at least eight days. Its sensitiveness to 
 light increases thereby, until at last insolubility of 
 the film is produced. If there is a suspicion that 
 the gum arable is adulterated, then the arabin acid 
 is precipitated with alcohol, and the gum washed, 
 dried, and afterwards dissolved in the necessary 
 quantity of water. 
 
 It is a condition in obtaining a good film that 
 the copper employed be perfectly even and flat. 
 If the plates are in any way bent or have partial 
 elevations or depressions they are useless ; on one 
 hand because they make the equal distribution of 
 the solution impossible, on the other hand an 
 absolute contact with the negative cannot be 
 obtained. If there is no polishing machine avail- 
 able the best way is to buy the copper plates ready 
 polished. They are then cleaned with finest emery 
 powder until free from grease and flowed under the 
 tap. The coating with the solution is done in a 
 similar way as with albumen with this difference 
 only, that after the first coating a second is 
 applied, which has to be flowed off in a contrary 
 direction. The whirling has to be prolonged, but 
 not too quick, and the plate dried carefully with 
 heat by keeping it in a horizontal position. Too 
 much heat makes the film easily crack, and though 
 the cracks may be hardly perceptible the plate in 
 such a state will, of course, be useless. The 
 
n6 
 
 HALF-TONE 
 
 drying is done in a few moments. The duration 
 of exposure is, on account of the thickness of the 
 film, a little more than for albumen. After the 
 exposure the picture should be seen in a soft 
 brown colour on a brilliant golden yellow ground. 
 The plate is put into lukewarm water, and the 
 film allowed to soften at least for five minutes, 
 whereby a swelling up and crinkling in the 
 shadows indicates over-exposure. After this place 
 the plate in an aniline bath to make the picture 
 more visible, for instance, in a solution of methyl 
 violet in water, which colours the image intensely 
 either in a few seconds or several minutes, accord- 
 to its strength. After all the parts which have 
 not been acted on by the light are washed away 
 under a strong rose tap, the picture should stand 
 like a blue print on the bright metal. A blue veil 
 between the dots and lines shows that all the 
 soluble gum has not been washed out. This is, by 
 reason of over-exposure, difficult to attain with 
 cold water. In such case if the shadows cannot be 
 opened sufficiently, use warm, or even hot water. 
 We thus have a greater latitude m exposure, with- 
 out impairing the result. If the film cannot be 
 washed out evenly, remaining dark-coloured and 
 indistinct in places, there has been faulty contact 
 in the printing frame, and the plate has to be pre- 
 pared again. The dots acquire their full sharpness 
 only after drying. The plate can be left for a 
 
ON THE AMERICAN BASIS. 
 
 117 
 
 short time in a warm room, but the best way is to 
 flow it with alcohol, whereby the aniline is for the 
 most part washed away. When fully dry, which 
 will be in a few moments, the hardening or 
 enamelling of the film follows. The state in which 
 the plate is before enamelling, would hardly offer 
 much resistance against mechanical injury, much 
 less to the action of the acid, unless a solution of 
 perchloride of iron in alcohol was used. The plate 
 is taken with a pair of tongs and gradually warmed 
 over some source of heat, for instance, a single or 
 up to a three-fold Bunsen burner. After some 
 time a change is noticeable. The blue gets pale, 
 then ashen grey, and entirely vanishes at last, the 
 aniline being destroyed by the heat. In this state 
 no trace of a picture is to be recognised on the 
 plate. The metal has an even yellowish red colour. 
 Gradually some parts begin to take a feeble brown 
 colour, the shadows first appearing with increased 
 strength, and an oxidation of the surface of the 
 copper goes hand in hand with the appearance 
 of the darker and darker shade of the picture. The 
 latter gets covered with a brilliant golden and 
 infinitely thin film. If at the same time the 
 picture has darkened to a deep chestnut, the burn- 
 ing of the plate is accomplished. Otherwise the 
 plate is carefully heated further, whereby the 
 brilliancy of the copper changes more into a 
 reddish colour, and in places vanishes altogether, 
 
n8 
 
 HALF-TONE 
 
 giving place to a dull yellow red with a dazzling 
 brilliancy. It is now high time to take the plate 
 from the stove and cool. 
 
 A well treated plate should be as follows :— 
 From the clear and brilliant ground of copper, 
 which is free from any trace of adherent gum, the 
 piclure appears in a soft chestnut brown colour 
 like an albumen photo. The film forms a relief of 
 discernible height, the dots have a pyramidal shape, 
 and enlarge to their base. Examined direclly 
 vertical every dot appears to have a ring 
 round it. We notice also that as a rule, 
 particularly with films of considerable thick- 
 ness the finest dots in the shadows are not 
 entirely washed out down to the ground of 
 the copper. This is because the rays of the sun 
 have crossed inside the film, and hardened the 
 layer of gum next to the copper. Under some 
 circumstances this is no disadvantage, as the 
 etching liquid attacks these spaces last, when the 
 lights have already a moderate depth, and it is 
 thus not so easy to etch the shadows too grey. 
 The hardness of the relief and its adhesion to the 
 copper is very considerable, and mechanical 
 injuries cannot easily result. Scratching with the 
 finger nail is impossible. The colour of the piclure 
 should be uniform in all parts — a deep chestnut 
 brown. Dark patches locally are caused by 
 depressions in the copper, producing a thicker 
 
ON THE AMERICAN BASIS. 
 
 119 
 
 film in those parts when coating the plate, and by 
 want of contaa between the negative and film 
 in printing. This as a rule is readily recognisable 
 on the plate when it leaves the aniline bath. In 
 some cases a strong washing under the water tap, 
 or pouring hot water on these plates is of use, but 
 generally a fresh plate has to be prepared. If on 
 the other hand there are several patches which are 
 too light, with a tinge of yellowish green, the film 
 in these places was too thin, and a danger of over 
 etching exists. The cause of these thin places lies 
 also in the unevenness of the copper, or in too 
 vigorous whirling, or in the solution being too thin. 
 Plates of large size particularly are seldom entirely 
 even, and give most difficulty. If entire evenness 
 were not such an important faftor, plates as thin as 
 paper could be used, the cost being, of course, far 
 less. For instance where there is an eleclrotyping 
 plant at hand, such plates prepared by galvanic 
 deposition on lead or silvered copper plates might 
 be had almost for nothing, as has been done by the 
 Moss Engraving Co., in New York. Any desired 
 thickness may be attained and the purity of eledtri- 
 cally deposited copper is beyond question. Nearly 
 pure copper is of a light red colour, and this is 
 most suitable for the process. Numerous alloys of 
 copper of a dull yellow colour have been brought 
 into the market in New York, but experience with 
 such metal has been unsatisfactory, and users 
 
120 HALF-TONE 
 
 have returned to pure copper. The alloys do 
 not always show on burning, the nice brilliancy 
 of colour which is such an important point 
 m recognising the necessary duration and 
 strength of heating. Besides, the etching 
 process does not always progress with the desired 
 certainty. Even when good copper is used, if the 
 washing out in development has not been sufficient 
 the plates will not burn clean, much less etch 
 evenly. If the burning-in has been carried too far 
 until the colour is nearly black, the film in many cases 
 cracks, and the print, through partially carbonising 
 becomes useless. Yellow films, which are feebly 
 burned are also useless, because they get too soft 
 in the etching bath, and naturally result in the loss 
 of the plate. 
 
 What I have said on the printing of copper 
 equally applies to brass, but this metal is not much 
 used. There is no sufficient reason for departing 
 from copper. Of course, enamel prints can also be 
 made on zinc, but the latter does not stand so well 
 such a high temperature. It changes its structure, 
 becomes crystallised, breaks by bending, and etches 
 slowly with great roughness. If zinc is chosen as 
 the printing metal, albumen gives the best results. 
 
 In a similar way to that already described the 
 other enamel preparations are used, and those who 
 know how to work with one will be able to handle 
 them all. Fish glue preparations require to be coated 
 
ON THE AMERICAN BASIS. 
 
 121 
 
 more thickly than gum, if they are to have the 
 same resistance to the acid. A modification in the 
 character of the negative is consequent upon this. 
 As already mentioned the dots in the print have a 
 pyramidal shape, and this is accentuated with glue. 
 A strong printing of the dots being necessary, a 
 slightly longer exposure renders them larger at 
 their base. If the clear spaces in the high-lights 
 of the negative are very small, this spreading in 
 the printing is an advantage, the danger of over- 
 etching being lessened. But if the dots in the 
 shadows of the negative are very fine, or are not 
 very dense, then it is nearly impossible to develop 
 them (without losing the delicate detail) so that 
 no blurred patches remain. Thus negatives for the 
 glue preparations must be well closed in the lights 
 and open in the shadows, that is to say they must 
 have solid dots in the latter portions. Negatives 
 which give good results with gum are often useless 
 for glue, except when the solution is thinned down. 
 The most feeble relief is given by enamel prepara- 
 tions with albumen alone, for instance, formula 
 III. They require, therefore, negatives with clear 
 glass shadows, broken up by very fine dots, and 
 with open lights ; negatives for the gum processes 
 stand about midway in these requirements. Fish 
 glue has one advantage over the gum, viz., its high 
 solubility in water, which shortens the develop- 
 ment a good deal, and has further the quality that 
 
122 
 
 HALF-TONE 
 
 the films never crack. A good kind of fish glue is 
 Le Page's Liquid Glue, manufactured by the 
 Russia Cement Co., Gloucester, Mass., U.S.A. 
 If we want it more purified, which for the most 
 part is superflous, some albumen is added to the 
 solution, which is well shaken, heated until 
 the albumen coagulates, and filtered. In making 
 up formula I. the fish glue is dissolved separately 
 with 4 ozs. water, the bichromate in 2 ozs. 
 of water, and the chrome alum in 1 oz. of water. 
 After dissolving all together, the alcohol and 
 ammonia are added. Owing to the solution not 
 
 Fig. 42. 
 
 keeping well, and the fadt that it is easily 
 prepared, it is advisable not to make more than 
 can be easily used in one day. By working with 
 very fine screens, as, for instance, 1 50 lines to the 
 inch, thick films are out of the question, and it 
 would be useless to adopt the above formula with- 
 out first thinning it with water. 
 
 Retouching of the print is very simple, and 
 is limited to stopping-out lost dots caused by 
 dust and impurities in the collodion, the stripping 
 collodion, or the printing solution. In this opera- 
 tion the hand-rest (fig. 42.) is useful, the hand 
 
ON THE AMERICAN BASIS. 
 
 123 
 
 resting on this whilst working. For albumen 
 printing ink, and for enamel, asphalt varnish is 
 generally used, both being thinned down with 
 lavender oil ; or shellac mixed with aniline colour 
 may be used. The work is quickly done with 
 well worked and pointed camel hair brushes and 
 a strong magnifying glass with small field, but 
 not too short focus (so as not to come into conflict 
 with the brush). It is not even necessary to imitate 
 striaiy the shape of the dots, the engraver being 
 able to take away in a moment any irregularities 
 with a few strokes of the graver. One must guard 
 against the fingers coming into contact with the 
 film when retouching, as the slightest deposit of 
 grease from the skin will disturb the evenness of 
 the etching process. From the retoucher the plate 
 goes to the etching room, and we will there watch 
 its further progress. 
 
124 
 
 CHAPTER V. 
 
 ETCHING. 
 
 Before going on to speak of the etching 
 process I should like, for a few moments, to direct 
 attention to the point of view from which the 
 etching should rightly be conducted. We have seen 
 how the original is broken up into dots, and how 
 the divided negative, by means of various prepara- 
 tions, is printed, and attains the necessary acid- 
 resisting properties. The print shows a picture 
 with the half-tones in dots, and how by enlarge- 
 ment the dots combine and form lines. From 
 these dots and lines all the details of the original 
 are composed. The centres of the dots being the 
 same distance apart, the formation of a detailed 
 picture is produced, with light and shade, by 
 changes in the shape and size of these dots, which 
 vary from almost imperceptible fineness to such a 
 size that they merge into each other, and form an 
 evenly flat surface without detail. From 400,000 
 to 1,800,000 dots, according to the fineness of the 
 
ON THE AMERICAN BASIS. I25 
 
 screen, are contained in a half-tone of about 7x5 
 inches. Strictly speaking, the changes in size of 
 these dots, by reason of their close proximity and 
 smallness, are very slight. But besides the change 
 in size the dots undergo in the same manner a 
 change in shape, which is more marked in propor- 
 tion as the original is rich in detail, and according 
 to how sharply the focussing is done, as the dots 
 are thereby forced to conform to the lines of the 
 original. In this way very differently shaped 
 figures, with characteristic, sharp outlines, are pro- 
 duced, but of minute proportions. Fine modulation 
 in the high-light parts is often attained through 
 such insignificant differences in the shape and size 
 of the dots as can be only perceived with a magni- 
 fier, and only give value by their effect in mass. 
 
 If upon this consideration we draw a conclu- 
 sion as to the nature of the etching, we see that 
 the leading idea is that, corresponding to the fine- 
 ness of the print, the deepening has to be conducted 
 in a very careful and exact manner. Having to 
 deal with such insignificant, yet nevertheless such 
 important, transformations in the shape of the dots, 
 it follows that we must endeavour to preserve in the 
 etching their characteristic shapes. The parts most 
 exposed to the destructive action of the acid are 
 the isolated dots. They have a tendency to round 
 off and diminish, bringing about in this manner a 
 loss of those little differences by which the delicate 
 
126 
 
 HALF-TONE 
 
 shades are expressed. In a less degree the dots 
 are attacked in the lights, where they are isolated 
 on all sides, and also where they are joined together. 
 The uneven action of the acid results in the latter 
 being disconnected, and an abrupt transition from 
 light to shadow results at the expense of weakening 
 the whole, because the isolated dots are more 
 quickly etched finer than those which are in 
 contact. The danger of losing detail in the lights 
 and softness can only be remedied apart from 
 making the film fully acid-resisting by omitting 
 rocking, brushing, and rubbing, as much as pos- 
 sible. The more the etching brush is used, the 
 quicker the etching advances, but the lights are 
 rendered proportionately whiter, whilst the shadows 
 are relatively kept back, and the whole impression 
 is harder. For forming an acid-resisting film the 
 enamel preparations on copper are unsurpassed, and 
 their general advantages are not to be under- 
 estimated. Those who are familiar with the 
 etching of photogravure plates know how quietly 
 and evenly perchloride of iron etches compared 
 with the turbulent action of nitric acid on zinc. 
 The enamel films are also strong enough to allow 
 the plate to be deepened with one etching, without 
 greatly reducing the dots, and it is so much easier 
 because the plates can be left still in the bath. As 
 to the necessary depth of the plate no exact guide 
 can be given, because plates are subject to many 
 
ON THE AMERICAN BASIS. I27 
 
 different circumstances, as for instance the fineness 
 of the screen, and the quality of the printing and 
 paper. In any case, shallow-etched plates, if they 
 are only deep enough to give clean prints, are to be 
 preferred on account of their softness and delicacy. 
 Considerable depth is only in its proper place where 
 the printing leaves something to be desired. 
 
 Arrangement of the Etching Room after 
 the American Pattern. — Line work is generally 
 etched on zinc in America, but in a radically 
 different manner to the so-called Austrian or 
 French etching process. First the deep etching 
 is omitted as an obsolete and almost forgotten 
 process. Then the plates are not rolled up in 
 order to cover the sides of the lines whilst obtaining 
 the depth. Instead of this, resin powder is brushed 
 on to the sides of the lines from four directions, 
 melted on, and the step formed is smoothed away 
 in the etching. This is repeated three to five 
 times, and in this manner the clean-etching 
 (finishing) may be omitted. It is no conjuring for a 
 good etcher to finish a line plate in half-an-hour or 
 less. In principle half tones are in no way 
 different from line work, and generally the same 
 method of etching them is observed. 
 
 To the arrangements of the etching room 
 belong two flat boxes with covers, containing 
 sieved resin and dragon's blood respectively. 
 Dragon's blood is a vegetable resin, which in its 
 
128 
 
 HALF-TONE 
 
 pure state has an intense red colour, and is used to 
 cover the steps of the etching. This is applied 
 with a four to six inch thick camel hair, such as is 
 used for the finest etching. The finest resin 
 powder is obtained by grinding in the colour mill. 
 The resin is pulverised in a mortar, well mixed 
 with water, and the thick liquid poured into the 
 
 Fig- 43- 
 
 mill. In establishments with power, and few are 
 without it in America, there is no difficulty in con- 
 necting the mill with the engine. The thick liquid 
 when well ground is spread out on a plate to dry, 
 and finally sieved through bolting-cloth. There is 
 nothing new to say about the etching tubs in use. 
 They have generally the shape of fig. 43, are well 
 pitched inside, and provided with an outlet. The 
 
ON THE AMERICAN BASIS. 
 
 129 
 
 heating of the plate over a Bunsen burner is not 
 desirable, except with plates of small size, because 
 even heating is difficult, and besides this the plates 
 are apt to bend, having to be held with tongs. 
 Where no steam is available, a gas stove (fig. 44) 
 with a series of Bunsen burners will do the same 
 service. Many etchers prefer to take the stove 
 plate off, and fix instead a wire grating or grid 
 a little higher than the table. By means of an 
 iron hood the heat is distributed as evenly as 
 
 Fig. 44- 
 
 possible. The plates are taken up with tongs or 
 carried on little shovels of the shape illustrated by 
 fig. 45. To cool the plate bellows are used, or the 
 hot plate is laid on a heavy iron slab. Another 
 way is to rub the back with a rag wetted with cold 
 water. Turpentine serves to clean the plates when 
 etched. If the heavy first cost is not objected to, 
 the best thing is to buy a large iron or lead trough, 
 filled with concentrated potash solution ; the 
 plates to be cleaned are placed on a rack having a 
 I 
 
I30 HALF-TONE 
 
 handle by means of which the whole is dipped 
 into the solution. Here they remain until all the 
 colour is destroyed, and the resin dissolves. For 
 covering the back and margin of the plates, 
 asphalt or shellac varnish is used. In case of 
 emergencies, one or more leather rollers with 
 accessories need to be at hand. 
 
 The Practice of Etching.— The dusting 
 and melting of the resin upon the half-tone 
 albumen print is done in the ordinary 
 way. The plate is made as warm as 
 the hand can bear, the powder being 
 then put on thickly, and brushed 
 with a quick but light movement 
 until the bare parts of the plate are 
 clean. Care must be taken that, 
 especially in the shadows, there is 
 no resin left adhering, as this will 
 obstruct the even action of the acid. 
 Resin melts easily, and the heating 
 should therefore be done slowly and carefully, and 
 not more strongly than can be recognised by the 
 melting of the resin ;md changing colour on the 
 surface. On account of the easy melting of resin, 
 many etchers prefer a mixture of it with dragon's 
 blood, which has a higher melting point. The 
 latter resin is not suitable by itself for the first 
 dusting, on account of its friability, and lack of 
 adhesion to the zinc when melted. The acid bath 
 
ON THE AMERICAN BASIS. I3I 
 
 is strong enough when it has the strength of 
 vinegar to the taste, thus containing one to two 
 ounces to the quart. With slight rocking of the 
 bath, and as little brushing of the plate as possible, 
 the progress of the etching solution is watched. 
 Often sufficient depth is attained with one etching. 
 If this is not t-he case, there are several ways of 
 preparing the plate for the second etching. The 
 plate, whilst wet, may be rolled up with transfer 
 etching ink by using a good glazed roller, and 
 charging the roller with very little ink, so as to 
 avoid the formation of steps in the etching, and 
 thus save the clean-etching. These two methods 
 are too well known to need detailed description. 
 Every etcher is familiar with them. But the way 
 in which the etching is continued in America would 
 be new to many workers in this country. 
 
 The first etching has to be so deep that the 
 ground of the metal, and particularly the sides of 
 the dots and lines, are etched without roughness, 
 and this applies to line work as well as half-tone. 
 The plate is drained off, dried on the stove, and 
 heated so strongly that it can hardly be held in the 
 hand. In this state the plate is conveyed to the 
 dusting box and heaped up well with the dragon's 
 blood. The resin, which has been rendered sticky 
 by the warming, takes the dragon's blood well, and 
 the drawing is covered with a layer of red resin. 
 The plate is laid on the left-hand corner of the box, 
 
132 
 
 HALF-TONE 
 
 and the excess of powder is dusted off with a camel 
 hair brush, but the brushing must be only in one 
 direction, from left to right across the plate and 
 back into the box. The intermediate spaces of the 
 picture which are already sufficiently deep are 
 filled up with powder, whilst in the lighter parts 
 the zinc appears clean again. On the left side of 
 each dot or line a slight layer of dragon's blood 
 remains, which attaches itself firmly to the step 
 formed by the previous etching, and this layer is 
 sufficient to protect the dots in this place from 
 over-etching. The quantity of powder deposited 
 can best be noticed by holding the plate horizontally 
 away from the light, and looking at it in an oblique 
 direction. The powder is now melted on, whereby 
 it changes its colour to a dark brown. The plate 
 is cooled off until warm enough to repeat the above 
 operation again, with the difference that the brush- 
 ing is done in an opposite direction. In this 
 manner a second quarter of the sides of the dots or 
 lines is covered with the powder, whilst the ground 
 of the picture remains free from it. The plate is 
 heated again, and the brushing and melting con- 
 tinued for a third and fourth time in direction at 
 right angles to the last, as shown by the arrows in 
 the diagram (fig. 46). In the end, every raised 
 part of the drawing is entirely surrounded by a 
 narrow wall of melted resin, as illustrated by the 
 dot (fig. 47). The operation is not entirely easy, 
 
ON THE AMERICAN BASIS. 
 
 133 
 
 and requires practice and experience. The manner 
 of handling the brush cannot be explained. If the 
 heat applied in the first operation was not sufficient 
 the picture does not take the dragon's blood readily 
 in the latter heatings, and it is difficult to brush the 
 resin from the ground to the sides of the lines or 
 dots, the resin in a certain measure smearing the 
 zinc, and leaving streaks. If the plate is too hot when 
 introduced into the dragon's blood the latter sticks 
 
 
 
 
 *? 
 
 
 
 ■ 4 
 
 i 
 
 1 
 
 — > 
 
 Fig. 46. 
 
 Fig. 47- 
 
 everywhere, and cannot be brushed away from the 
 ground of the plate. In this case the best thing to 
 do is to clean the plate and roll it up with ink. If 
 the plate is over-heated the resin commences to 
 smoke, and that is a sign that it is partially 
 carbonised, and in this state has lost its acid- 
 resisting qualities. 
 
 In the second etching, the bath is strengthened 
 with a certain percentage of acid, the endeavour is 
 to obtain the desired depth on the one hand, and 
 
134 
 
 HALF-TONE 
 
 on the other the smooth etching off of the fringe 
 formed by the resin. If this fringe is too great — 
 and beginners will, as a rule, get it too large — a 
 step is left which can only be removed by a finish- 
 ing etch. A properly-conducted etching should by 
 each succeeding bath remove the step formed in 
 the previous bath, and so save the fine etching, 
 If the resin after the second etching is deep, clean, 
 and sharp, the resin, ink, and backing varnish are 
 washed off, and a proof taken from the plate. 
 
 For etching enamel copper and brass plates, 
 commercial, technically pure perchloride of iron is 
 dissolved in a much smaller quantity of water, i.e., 
 water to the extent of one-third the weight of the 
 perchloride. Test the solution to about 35 0 
 Beaume, and filter. A bath long in use turns to a 
 green colour, and is thick and muddy from the 
 separated oxide, etching very slowly. Suggestions 
 have been made for purifying such solutions, so as 
 to bring them into a fit state for use again, but I 
 see no advantage in business-practice in it. The 
 profit derived in one way would be lost in another — 
 in trouble and waste of time. The best way is to 
 filter and dilute the old bath, using it for a few 
 plates and then throwing it away. A handle (fig. 
 48), with two stirrups as illustrated, may be made 
 of strong insulated leading-wire, as used for the 
 electric arc lamps, or in default of this a piece of 
 iron wire painted with lac varnish. This can be 
 
ON THE AMERICAN BASIS. 
 
 135 
 
 bent to suit all sizes of plates. The copper plate 
 to be etched, with its back coated with varnish, is 
 fixed in this handle by two diagonal corners in the 
 stirrups, film downwards, thus forming a good 
 plate holder, which for quality and cheapness is 
 unsurpassed. The plate thus comes film down- 
 wards into the perchloride of iron solution, which 
 directly commences to attack the copper. The 
 plate is moved a few moments to and fro, making 
 
 Fig. 48. 
 
 sure that everything is in proper order, especially 
 that there are no air bubbles under the plate, and 
 it is left for five or ten minutes to itself. After this 
 it is taken from the bath, the perchloride of iron rinsed 
 off, and the plate examined with a magnifier to ascer- 
 tain the depth obtained. It is a pleasure to look at 
 such a plate. It seems as if a picture had been 
 produced on the red ground of the plate as if by 
 magic. Every dot stands there sharp and un- 
 
136 
 
 HALF-TONE 
 
 injured, and the intermediate spaces are etched 
 out as smooth and round as can well be imagined. 
 If the necessary depth is attained, there is nothing 
 more to do than to dry the plate, to clean the 
 deposit away in the deep parts with a hard brush, 
 and to take a proof. Some probable causes of 
 failure I have partly mentioned in the preceding 
 chapter. Softening of the film through insufficient 
 burning is often perceived in time by scratching 
 the margin with the finger nail. If this is the case 
 and the coating of the plate is otherwise uninjured, 
 the film is washed off with hot potash solution, and 
 rolled up. If the acid does not attack evenly, and 
 particularly if the dark parts will not open, then 
 the print was over-exposed, or not sufficiently 
 washed out, or the contact in the copying frame 
 has been imperfect. In this case use the etching 
 brush, and in extreme cases even a hard bristle 
 brush, and by this means allow the perchloride of 
 iron to attack the copper. If the film has un- 
 usually slight resistance to the acid, the burning 
 
 has been too short, or it has been extremely long 
 
 which can be determined in either case by the 
 colour of the enamel film — or the coating was too 
 thin. 
 
 Except for these defects, the result of faulty 
 manipulation, it is possible by means of rolling up 
 or light etching, to improve at the right moment 
 and in the right place the result of a faulty negative, 
 
ON THE AMERICAN BASIS. 
 
 137 
 
 and to save the work. But I repeat, all these 
 tricks are only botchy work. In making them a 
 rule we should fail to appreciate half-tone as a 
 mechanical process. The less the plates need 
 artistic retouching the more successful will be the 
 result. Retouching implies a previously-incurred 
 fault, and no one will contradict me if I hold it 
 more important to keep in mind the avoidance of 
 these faults from the beginning, than to waste our 
 best faculties in repairing them when they have 
 happened. We are so easily induced to let pass 
 a slightly faulty negative, with the consolatory 
 excuse that the defect can be surely remedied by 
 the printer or the etcher, or without fail by the 
 engraver. The printer thinks he has done his duty 
 in having printed the negative mechanically, and 
 does not feel induced to do more, even if he could. 
 He may. get even, in addition, a few ugly dirt 
 stains on his plate, but " they are so easy to 
 retouch." The plate is also a little over-exposed, 
 but this does no injury at all, because " the etcher 
 can leave it so much longer in the bath." This 
 the etcher does ; even something extra. He 
 brushes and brushes until the dots are as fine as 
 possible, yet because the shadows are heavy and 
 blurred, the shading in the lights has gone, softness 
 is out of question, and it is not altogether his fault. 
 Where too, are the engravers, who are armed with 
 roulette and burnisher ? If the engraver who 
 
i 3 8 
 
 HALF-TONE 
 
 receives the plate in the last instance is over- 
 whelmed with work, then we can conceive what 
 kind of result will be forthcoming. And this all 
 through mere bagatelles of faults which could 
 have been very easily avoided. 
 
139 
 
 CHAPTER VI. 
 
 FINISHING WORK. ENGRAVING. 
 
 From the etched plate, a rough proof is next 
 taken. The fate of the plate depends on this 
 proof-taking, and care should be taken in this 
 proceeding. To use for the sake of economy, cheap 
 paper and bad ink would be bad policy, the proof 
 having to decide whether the plate is serviceable or 
 not, and to guide the engraver as to the neces- 
 sary retouching to be done. It is useless to sup- 
 pose that in all cases, a plate, except for trimming 
 the margins, is ready for printing from when it 
 leaves the etching bath. Notwithstanding that the 
 manipulations already described form the principal 
 part of the work, it is left to the engraver and 
 finisher to amend any faults which have arisen in 
 the foregoing processes, to correct light and shadow 
 to the standard of the original, to bring up lost 
 details, to set up pointed lights, to cut vignettes 
 running into pure white, in short, to put the last 
 touches on the work, and to give the reproduftion 
 
140 
 
 HALF-TONE 
 
 the highest attainable degree of perfeftion and 
 artistic merit. 
 
 F or this the rough proof serves as a guide, 
 and it is conceivable that its quality must not be 
 indifferent. If the proof is satisfactory, the depth 
 of the plate sufficient, and there are no bad faults 
 present, then the engraver cuts with the graver the 
 
 Fig. 49. 
 
 margin line. When previously speaking of strip- 
 ping the negatives, I mentioned the easiest way to 
 obtain a sharp margin line. The margin of the 
 plate prints black, in consequence of the straight 
 cutting of the edges of the film, enabling the en- 
 graver to determine, by scratching with the graver, 
 the thickness of the margin line. The superfluous 
 
ON THE AMERICAN BASIS. I4I 
 
 edge is removed with the bevel plane specially con- 
 structed for the purpose, or better with the routing 
 machine, as used in America since the establish- 
 ment of the reproduction business, and saves the 
 troublesome, time-absorbing and unhealthy opera- 
 tion of deep etching. The principle of all these 
 machines is that a cutter rotates at a high speed 
 and can be moved along the lines to the desired 
 depth. Cutters of different sizes (see fig. 49 in 
 natural size) enable different large spaces to be 
 taken away even to the diameter of only a few 
 millimeters. The advantage of the routing 
 machine versus the etching process is an enormous 
 one, and it is astonishing that this machine 
 has made so little progress in Europe. Fig. 50 
 shows the system most in favour in America. The 
 plate is nailed on to a board, and together with it 
 fastened to the machine table immovably by 
 means of clamps. By two levers, of which the 
 left lies on a bracket and can be lifted, lifting the 
 cutter at the same time, the latter is moved in all 
 direaions over the plate. Two treads on the base 
 of the machine bring the cutter into and out of 
 action, respectively raising or lowering it to 
 deepen plate while, working. A screw applied 
 at the upper part of the cutter, allows its being 
 raised or lowered, and thus the plate can be routed 
 out in different depths, shallower in the fine parts 
 and deeper in the larger spaces, or allowed to go 
 
Fig- 5°- 
 
ON THE AMERICAN BASIS. 
 
 143 
 
 right through to the wood. One horse power is 
 sufficient for driving the machine, and by this the 
 cutter should make about 9000 to 12,000 revolu- 
 tions in one minute. The shape here illustrated 
 is the Radial Arm Routing Machine of Royle. It 
 costs ^57, and plates of 40 inch length can be 
 routed with it. In other systems, which are not so 
 good, the cutter is fixed whilst the plate is moved 
 to and fro under it. 
 
 In routing the margins of a half-tone the 
 cutter is run along the marked line of the engraver, 
 but does not cut away the outer margin, leaving 
 this to give a better start for the ink roller, when 
 taking a clean proof. Where no routing machine 
 or shoot block is at hand, the etcher has to under- 
 take the tiresome work of deep etching, by coating 
 the block to the marked border with leather 
 varnish and then performing the deep etching in 
 the ordinary way. 
 
 Thus prepared, the plate goes back to the 
 engraver. Occasional markings or scratches 
 derived from the foregoing manipulations or badly 
 retouched spaces, are worked over with the graver, 
 until the dots have the shape of the neighbouring 
 dots, and in printing do not show any defective- 
 ness. Holes eaten away by the acid are more diffi- 
 cult to repair, and they appear white in the print. 
 There is nothing to be done but to solder them, 
 equalize the surface with the scraper, and engrave 
 
i 4 4 
 
 HALF-TONE 
 
 out with the tool. For lightening too deep 
 shadows which are without detail, the roulettes 
 (fig. 51) are used, the teeth of which have about 
 the distance of the dots of the screen. Sharp 
 contours and outlines can be brought up with 
 them, giving the picture more life and roundness. 
 
 Fi e- si- Fig. 52. 
 
 Strong high-lights are often taken out or the dots 
 are cut down to the utmost fineness. Where it is 
 required, on the contrary, to deepen the spaces 
 which appear too light the burnisher is 
 applied (fig. 52). It is rubbed with moderate 
 pressure on the parts concerned, whilst carefully 
 
ON THE AMERICAN BASIS. 
 
 H5 
 
 keeping to the contour, and the dots are made a 
 little larger. They will thus appear slightly 
 darker in the print. In this manner particularly, 
 the details in the high-lights are brought into 
 evidence, and grey shadows without strength are 
 deepened. We must not forget that by polishing 
 the plate with the burnisher, the surface in 
 these parts lies a little deeper and will not 
 print without overlaying, which if not done 
 would give the contrary of the desired effect. 
 If the plate was printed with enamel, and 
 needs a thorough treatment with the burnisher, 
 it will be better to wash off the film with a hot 
 soda or potash solution, as the enamel would 
 offer an important resistance to the burnisher. 
 Often the film is burnished only in the lights and 
 allowed to stand in the shadow. The thickness of 
 the film on the darker parts foims then a kind of 
 natural relief, through which the lights receive less 
 impression in printing. Shallow etched plates 
 must be carefully treated in using the burnisher, 
 or they will be rendered more shallow, and fill up 
 in the press. 
 
 Preparing and Clean Proving of the 
 Plates.— Hand in hand with the work of the 
 engraver goes the skill of the proof printer. 
 It seems so easy, yet it is so difficult to obtain a 
 perfect proof. It is to the interest of the manager 
 of the business to obtain the best possible printing 
 
 K 
 
146 
 
 HALF-TONE 
 
 result from the plate to be delivered, as this 
 determines the value of the block, and so gives a 
 pattern to the machine printer to follow in making 
 ready. The more beautiful the proof is, the more 
 excellent will the edition be, as the printer 
 endeavours to equal the proof as far as possible. 
 Many blocks made from suitable originals need 
 hardly any preparation for the handpress, being of 
 the same value of tone as the original picture. 
 But this is seldom the case, except in work of 
 small size. The making ready is done in a two- 
 fold way, from the surface and from the back ; the 
 first has for its object to remedy unevenness in the 
 metal, or to give more or less pressure to certain 
 parts. This is performed by taking a proof on 
 strong paper, and cutting out parts which print too 
 dark or not satisfactorily on account of the uneven- 
 ness of the metal. The parts which are intended 
 to print darker, such as the shadows, are cut out 
 of another proof, and these, with the sheet 
 corresponding to the lighter tones, are respec- 
 tively attached to a second proof, which serves as 
 a guide for the position of the pieces pasted on. 
 The whole picture, face down, is pasted on the 
 back of the block. The most important prepara- 
 tion is, however, the overlaying. The block is 
 placed in the middle of the press bed and the 
 position is marked. If there is no other arrange- 
 ment thjs js done by pasting two pieces of paper 
 
ON THE AMERICAN BASIS. 147 
 
 on the table, touching exactly with their corners 
 the two diagonal corners of the block. Then a 
 piece of glazed printing paper of sufficient size is 
 pasted in the middle of the press tympan, and a 
 proof is taken on it. On to this is later on pasted 
 the overlay, and in this way it is possible to cover 
 the block correctly in printing, if it is placed in its 
 correct position between the two paper marks. 
 Should the press not have a fixed tympan we can 
 manage it in a way by laying the block on one 
 folded half of a large, strong and smooth sheet of 
 paper, marking the position of the block by going 
 round it with a pencil, afterwards folding over the 
 second half of the sheet on to the block and taking 
 a proof. From fine tissue paper (the tissue being 
 of different thicknesses but free from any lumps) 
 proofs are taken, and parts of these are cut out as 
 overlays and pasted on to a proof on smooth stout 
 paper. This, in turn, is pasted on to the upper 
 part of the sheet on which the block is laid. The 
 idea is to produce a relief which at the moment of 
 impression gives a different pressure to various 
 parts of the plate, strong in the deep shadows, and 
 softer towards the high-lights, so that in conse- 
 quence of an unequal deposit of ink from the block 
 on to the paper, the print acquires more strength 
 and roundness. I have mentioned above that 
 through the work with the burnisher the surface of 
 the block on the overworked parts is hollowed. 
 
148 
 
 HALF-TONE 
 
 The effect is that by a flat printing these parts are 
 exposed to less pressure, and on account of this 
 fact the ink is not so well taken up. These parts 
 have to be overlaid, until the paper takes the ink 
 evenly. In this case the deepest shadows are cut 
 out from the printed tissue paper with a sharp 
 knife, keeping exactly to the contour, and they are 
 pasted on to the paper, to receive the overlay, 
 exactly in the same place as the shadows on this 
 proof. In this manner the deepest tones are over- 
 laid, then the parts which represent the second 
 deepest tone are cut from another tissue paper, 
 and pasted in the same manner on the overlay 
 sheet. This is also repeated a third time, and 
 under some circumstances a fourth time, to obtain 
 a gradation in the shadows. 
 
 With the deepening of the shadows goes hand- 
 in-hand a softening in the lights, and if this is not 
 sufficient for the lightest parts, then the latter are 
 cut out from the overlay sheet. If clean work is 
 to be produced, it must be a rule to cut the over- 
 lays a little smaller than the parts which you desire 
 to darken, and the cuttings out a little larger, the 
 latter, as stated, lessening the action of the 
 pressure, whilst the former increases it. In all 
 this work do not lose sight of the original. When 
 it is thought all that is necessary has been done, 
 cut out from the overlay two diagonal corners as 
 far as the margin of the picture, as shown in fig. 
 
ON THE AMERICAN BASIS. 
 
 149 
 
 53, paste the overlay on to the proof on the tympan, 
 and proceed to produce a proof. The smoother 
 the surface of the printing paper, the harder it is 
 calendered, and the whiter it is the better it 
 answers its purpose. The colour of the 
 paper, as well as of the printing ink— 
 with which the block gives nearly as many 
 shades as by colour printing — influences the 
 beauty of the print in a striking manner. Thin 
 
 L 
 
 Fig. 53- 
 
 paper, even if it is well glazed, makes the impres- 
 sion mealy looking, on account of its inclination 
 to wrinkle and break. Medium strong print- 
 board is most suitable. Also, do not economise on 
 the size ; nothing makes a picture more insignifi- 
 cant than a narrow meagre margin. In regard to 
 the printing ink, the best principle is that the most 
 expensive ink is the cheapest in the end. Being 
 better in distribution, less of it is used to cover a 
 considerable surface. It can be understood that 
 
HALF-TONE 
 
 one and the same colour will not work with equal 
 perfection on damp wood-cut paper, as on highly- 
 calendered hard and dry machine paper. The 
 difference of the distance and depth of the lines in 
 a half-tone and in a wood-cut makes this clear. In 
 comparison with the woodcut, where the lines are so 
 deeply cut out with the graver that the ground 
 cannot take colour under any circumstances, the 
 half-tone blocks are very shallow etched, corres- 
 pondingly to the considerable fineness of the dots 
 and the slight distance between them. There are 
 on the square centimeter 1500 to 8000 dots. The 
 rollers are not without influence on the quality of 
 the print, and every printer knows how sensitive 
 they are to temperature and dampness. Bad 
 rollers impair the quality of the ink. They should 
 be fairly soft, with an elastic surface, yielding to 
 the pressure of the thumb, but not so much as to 
 enter too deeply into the block. 
 
 To return to our proof : the block is rolled up, 
 placed exactly in position between the marks on 
 the printing table, and the black margin with a clean 
 mask covered up, the proving paper being held a 
 little hollow and laid in the centre of the plate. The 
 tympan bearing the overlay is laid down and the 
 backing, consisting of layers of calendered card- 
 board, is laid on, a proof being then taken under 
 moderate pressure. It is very seldom perfect the 
 first time. Generally either one part or the other 
 
ON THE AMERICAN BASIS. 
 
 15* 
 
 is not fully brought up and needs a further overlay. 
 Some shadows may be still too light, or the lights 
 have too much tone, and the engraver finds little 
 irregularities to remedy. At last the final touches 
 are given, and the proof, the fruit of a long series 
 of processes, is completed. 
 
 I may point out that the working together 
 in mutual understanding of the proofer and 
 engraver is a source of many advantages, 
 and a further assurance of a good result. It must 
 not be forgotten that in reproduction through a 
 screen fine details, which make, perhaps, the value 
 of the drawing, are often lost, and a sort of fine 
 veil seems to settle over the whole picture, allowing 
 strong contrast to stand out with fair vigour, but 
 effacing the feebler shades without leaving a trace 
 behind. How can this lost character be restored, 
 except by the burin and burnisher of the engraver 
 and the art of the proofer ? I do not only refer to 
 the proofer, but also to the machine printer. In 
 breaking up the whole of the picture into a grain, 
 the vigorous contrast between black and white is 
 lost, and cannot be preserved except by heighten- 
 ing it. In the most favourable cases only, could a 
 plate be good enough to need no further preparation, 
 and even then it would only be for a few proofs. 
 If an edition of thousands is required, how can dots 
 in the block, as fine as a needle point, be expected 
 to preserve their shape and deposit a minute patch 
 
HALF-TONF. 
 
 of colour, if they are exposed hundreds of times to 
 
 the same heavy 
 pressure required for 
 taking off the 
 colour in the 
 shadows. The 
 wearing down of a 
 block subjected to 
 such rough treat- 
 ment will at last 
 have attained such 
 J^^^gg0' |||| a degree that smudg- 
 
 ■■BB ^bIIIII ing ' l0SS ° f shar P- 
 4 ness, and deforma- 
 tion of the dots takes 
 place. The contrasts 
 vanish more and 
 more because the 
 colour is heaped up 
 in the lights, and 
 only the skill of a 
 clever printer can 
 prevent all this. It 
 is to be regretted 
 that in this matter 
 we far too fre- 
 quently transgress 
 by still adhering 
 to the usages of woodcut printing. Yet how 
 
ON THE AMERICAN BASIS. 
 
 1 53 
 
x 54 
 
 HALF-TONE 
 
 much more sensitive is a half-tone block to 
 the slightest difference of pressure, on account of 
 the excessively fine and close grain ? The detail 
 is dependent on changes in the shape of the dots, 
 so minute as not to be detected with a 
 magnifying glass, and only the action en masse 
 brings them into evi- 
 dence. Here is large 
 scope for the artistic 
 perception of the 
 m a c h i n e - m i n d e r — and 
 also for the careless ! 
 
 The Mounting of 
 the blocks is a purely 
 mechanical branch, to 
 which it is not necessary 
 to draw much attention, 
 as it is hardly within the 
 immediate province of 
 half-tone work. If there 
 is no special drilling 
 F 'f?- 56. machine, the holes for the 
 
 mounting nails are drilled in the plate with the 
 routing machine. The wood used is cherry or 
 birch ; it must, of course, be even and perfectly 
 dry. Well-appointed establishments are provided 
 with a planing machine, but smaller firms buy 
 their wood ready planed to the desired thickness. 
 It is cut with a circular saw to the right size — a 
 
ON THE AMERICAN BASIS. 
 
 155 
 
 little larger than the plate. If the latter, in the 
 course of the various manipulations — as, for 
 instance, in the etching — has been bent, it must 
 before nailing on to the block be hammered flat on 
 a heavy iron plate. Thin, broad-headed nails, 
 about 1 in. to f in. long, are mostly used ; screws 
 less seldom. If the blocks are of a very large size, 
 the wood is not used in one piece, but joined in 
 several parts, and if the lines of the drawing are 
 so close — this applies especially to half-tone — that 
 there is no space between them for the plate to be 
 nailed on, somewhat conical holes are drilled in the 
 wood from the back. The plate is placed with the 
 etched side down on an iron plate, the wood block 
 being fixed on to it by means of clamps, and the holes 
 filled up with soldering metal. Finally, the sides are 
 trimmed with the hand plane (fig. 54), or with the 
 power plane (fig. 55), so securing the accurate 
 squareness of the block. The exadt type- 
 height is measured with the instrument illustrated 
 in fig. 56. 
 
156 
 
 CHAPTER VII. 
 
 VIGNETTES. 
 
 The most difficult, but at the same time the 
 favourite kind of reproduction for the printing 
 press, are vignettes-*.*., pictures having no sharp 
 margins, but softened down until they run into 
 clean white. This circumstance makes the pro- 
 duction, the proofing, and the ultimate printing 
 difficult. The vignettes are obtained either by 
 hand engraving—as is generally the case in 
 America— or by the etching process; or the 
 subject can be masked in the first instance on the 
 negative. Recently vignettes have been obtained 
 direct in the camera by the action of the light, so 
 that the hand work is for the most part saved, and 
 is limited to the repairing of faults. 
 
 On the engraving of vignettes there is little to 
 say. A sure hand and a practised eye must be 
 combined with good taste. When the plate comes 
 from the engraver it is entirely covered with the 
 grain of dots without any distinct margin. By 
 
ON THE AMERICAN BASIS. 
 
 157 
 
 means of a point the engraver draws the exterior 
 limit of the vignette, as with blocks having a sharp 
 border, and the plate is deepened by routing or by 
 etching along the line marked. Then commences 
 the real engraving work, which is done by guiding 
 the graver between the rows of dots in two direc- 
 tions round the vignette, in such a way that always 
 nearest the outside edge the most is cut off the 
 dots, until the latter have attained at the extreme 
 margin the highest degiee of fineness. That this 
 operation is a difficult and time-absorbing one will 
 be quite understood. Therefore, the price of 
 vignetted blocks is higher. In the final printing, 
 on which the utmost care must be bestowed, the 
 rollers must be prevented from bearing too heavily 
 on the edges of the vignette or a black border will 
 result, and this is hardly preventive in rough printing; 
 but in fine work the print should, as in the original, 
 run into pure white. If the engraver, besides his 
 handiness with the graver, which can only be 
 acquired by long and continued practice, is not 
 without artistic understanding, he can bring up 
 some very nice effedts. The more strongly the 
 dots stand in the negative the less they are reduced 
 in etching, and the more difficult is the cutting of 
 the vignette, because the engraver has to enter his 
 graver further into the picture to secure the 
 softening down. It is therefore of advantage in 
 making the negative, as well as in etching, to take 
 
I58 HALF-TONE 
 
 care to obtain the highest fineness possible in the 
 dots. The etcher can render the engraver great 
 service by means of stronger brushing of those parts 
 lightening the borders in the etching. This is par- 
 ticularly easy with enamel prints, where the 
 vignette shows up on the copper like a photograph. 
 He etches the plate first to the ordinary depth, 
 washes the plate with water, dips a stiff brush — 
 such, for instance, as is used by oil painters — in 
 the solution of iron perchloride, and brushes the 
 edges of the vignette by steps, frequently 
 washing to prevent the iron forming perceptible 
 markings within the limits of the picture. We 
 can etch in this manner gradually to a very light 
 tone, and the troublesome stopping-out with 
 varnish is avoided. If we would do more, then by 
 all means call to aid the varnish, and. stop out the 
 parts which have attained the necessary lightness, 
 but it must be mentioned that it is very difficult to 
 work on an etched plate with a brush on account 
 of the running and spreading of the varnish in the 
 etched depths, so that a proper effecl: is hard to 
 obtain, and it is difficult to get a sharp line. 
 Therefore, whoever has a good engraver available 
 does better not to go into details in etching. It is, 
 at any rate, not so bad if one or another part 
 lightens up a little too much, because they can be 
 worked over with the burnisher. 
 
 It is another matter if you are compelled to 
 
ON THE AMERICAN BASIS. 
 
 159 
 
 have the entire vignette produced by the etcher. 
 Then the etcher must have the necessary taste, 
 and must strive to attain the effecl of the original 
 by partial stopping out and etching. But it cannot 
 be done entirely without the aid of the engraver 
 if we want to make a really good block for printing. 
 In the negative also we can very well help on a 
 vignette. Delicate lights can be well covered with 
 stopping out colour, and gradated contour painted 
 in. If we rub the film with the finger and a little 
 resin powder, then it is susceptible to pencil re- 
 touching, and for washes the same service is 
 rendered by " Mattolein." * To avoid the trouble- 
 some hand work it has been sought to produce the 
 vignettes in a mechanical way. Although this 
 process has been patented in America the idea is 
 not a new one, and the same thing has been done 
 from the earliest days of experiments with the 
 screen. For instance, if we first give through the 
 screen a full exposure, and then remove the screen, 
 and expose on the original further for a short time 
 that only the highest lights leave any impression 
 on the plate, then originates a correctly broken up 
 negative with the difference that the dots in the 
 
 * The Author assumes this, no doubt, to be commercially 
 obtainable, as probably it may be on the Continent. I have 
 not heard of it in England, but recently saw a formula in a 
 German jourjial far -'^a^tolein.J' It..censiifs..of ;.§piiats.of 
 turpentine, 5jpaiSt% a'hfl cjaifctfui 1 pail*— If R/j &!}*•. ; J • 
 
l6o HALF-TONE 
 
 whites are gradually veiled into the entire black. 
 When such a negative is printed the increasing 
 opacity of the veiled dots comes into evidence, and 
 results in small dots of increasing fineness on the 
 metal plate, until the light has no more action on 
 the sensitive film in the parts entirely opaque on 
 the negative. It is not to be denied that in this 
 way very nice gradations are obtained, but un- 
 fortunately the lights in the drawing are rendered 
 pure white, and this under some circumstances is 
 a great disadvantage of the process, against which 
 there is no remedy, unless the artist in the 
 drawing itself gives the lights within the drawing 
 more tone than in the background of the vignette. 
 With a Levy's patent half-tone dark slide with 
 screen regulated from the outside, I have attained 
 the closing up of the lights in a better manner, by 
 putting the cap on the lens after the regular 
 exposure, introducing a large stop and removing 
 the screen to its furthest distance, then exposing 
 further for a very short time.* The resulting action 
 is, according to what I have said in the chapter on 
 negative making, quite comprehensible. 
 
 * Such a method is readily attainable by means of the 
 screen adjustment gear, which is now generally in use in 
 England. — Trans. 
 
i6i 
 
 CONCLUSION. 
 
 I have endeavoured in the foregoing chapters 
 to describe as comprehensively as possible the 
 entire process of half-tone engraving, from the 
 retouching of the original at the outset, to the 
 blocking of the plate, so that this book may serve 
 even the beginner as a guide to a successful result. 
 Many other things seemed to me to be worthy of 
 attention, had I not been afraid, that through 
 methods which lay a little out of the direct way, I 
 should encroach upon the one process represented 
 in these lines. Everywhere are rising up new 
 methods, suggestions and experiments being made, 
 and other processes striving to come to light and to 
 overcome the until now unconquered screen. How 
 many years will it last, before we stand at a new 
 turning point in the history of half-tone ? Who 
 can tell ? But so long as new experiments stand 
 alone and untested, so long must they be without 
 the sanction of business practice. I hesitate to 
 take them up in this little book, for not one of the 
 modified processes indicated is likely to achieve 
 such fame as to surpass in beauty, and at the same 
 
HALF-TONE 
 
 time in certainty and speed, those I have described. 
 It is this trinity of advantages which makes the 
 strength of the half-tone process. 
 
1 63 
 INDEX. 
 
 PAGE 
 
 Apparatus for Negative Making 27 
 
 Albumen Solution 103 
 
 Coating Plate with 106 
 
 Acid-Resisting Film 126 
 
 Arrangement of Etching Room 127 
 
 America, Photo-Engraving in 13 
 
 Brass 120 
 
 Blocks, Mounting of 154 
 
 Wearing down 152 
 
 Wood for Mounting 154 
 
 Camera Swing 3 l 
 
 Copying Board 3 2 
 
 Clearing 71 
 
 Cutters 14° 
 
 Copper Plates, Cleaning and Coating 115 
 
 Purity of 119 
 
 Coating Plates 106 
 
 Dark Slides 35 
 
 Development, Duration of 63 
 
 Distancing the Screen, Results of 53 
 
 Dragon's Blood 170 
 
 Exposure, Duration of 65, 108, 116 
 
 Enamel Process in 
 
 Preparations, Recipes for .. .. .. .. 113 
 
 Etching Enamel Copper and Brass Plates 134 
 
 First 13 1 
 
 ,, Room, Arrangement of .. .. 127 
 
 Second 133 
 
 The Nature of 125 
 
 The Practice of 130 
 
 Failures 78 
 
 Fish Glue Preparations 120 
 
 Glue, Le Page's Liquid 122 
 
 Hand-Rest 122 
 
 Ink, Recipe for Rolling-up 103 
 
 Intensifying 7° 
 
 Influence of Light 63 
 
 Light in Studio 27 
 
 Lenses 48 
 
 Light Spaces, Deepening , , . , , , , , 144 
 
164 HALF-TONE 
 
 PAGE 
 
 Lightening Shadows 
 
 Making Ready ^6 
 
 Mounting Blocks 
 
 Negative Making, Apparatus for 27 
 
 Number of Dots ^4 
 
 Operating, Practice of Half-Tone 66 
 
 Originals, Reproducing 47 
 
 Over-Exposure 73, 110. 
 
 Photo-Engraving in America 13 
 
 Plate, Condition of a well treated 118 
 
 Holder, A Cheap 135 
 
 Plates, Coating , . . . 10 6 
 
 Preparing and Clean Proving the 145 
 
 Polishing Zinc gi 
 
 Prices of Blocks, Average 26 
 
 Printing, Frames for 97 
 
 Negative Films on Metal 84 
 
 Materials for 93 
 
 ,, Process 87 
 
 Proofer and Engraver, The 151 
 
 Proof Finishing 150 
 
 Taking . . . . i 39i I49 
 
 Reproducing Originals 47 
 
 Resin 128 
 
 Retouching the Print 122 
 
 Rolling-up Ink 103 
 
 Roulettes 144 
 
 Routing Machines 141 
 
 Screen, Distancing 53 
 
 Screens 40 
 
 ,, Cleaning 67 
 
 Prices of 45 
 
 Sizes of Dots . . . . . . 51 
 
 Stops, Aclion of Different Shapes of 58 
 
 Different Sizes of 56 
 
 Which is Best to Use? 62 
 
 Stripping and Reversing 81 
 
 Studio, Light in 27 
 
 Swing Cameras 131 
 
 Type-High Gauge .. .. 154 
 
 Vignettes, Engraving 156 
 
 Wages 25 
 
 Whirlers 93 
 
 Wood for Mounting 154 
 
 Zinc, Etching 89 
 
 ,, Polishing 91 
 
 ,., The . , 88 
 
SUPPLEMENT ILLUSTRATIONS 
 
 TO 
 
 ILLUSTRATE THE PROCESS 
 OF 
 
 HALF-TONE. 
 
I. Portrait Study by Fritz Grandt, Art Publisher, Berlin. 
 Half-Tone made in the Pra&ical Institute '6f W. Crorienberg. 
 (Student work of Willy Schafer). 
 
II. Portrait Study from a photograph by A. Brand, Malmo, late student in 
 the Institute of W. Cronenberg. 
 Half-Tone with Gaillard's Screen and Enamel Process. 
 
Portrait Study by Alex Brand, Malmo (formerly a student in the Institute;. 
 Half-Tone with Enamel Process by Hather, a student in the Institute. 
 
IX. Half-Tone Zinc Etching by Iwar Wendt, a student. 
 
X. Half-Tone Copper Etching by Enamel Process, 
 
 finished in one etching. 
 From a wash drawing by Friedrich Roth, a student. 
 
HALF-TONE ON THE AMERICAN BASIS. 
 
 N 
 
Specimen of Illustrations in 
 
 The Practical Photographer. 
 
 Monthly, 3d.; post=free, 56. Of all Dealers. 
 
 Percy Lund & Co., Ltd., + Memorial Hall, London, E.C. 
 
HALF-TONE ON THE AMERICAN BASIS. 
 
 This Book is entirely printed 
 with 
 
 Johnson's Transparent 
 
 'Rubberine 
 
 Regd. 
 
 Printers' Rollers. 
 
 The Best Half=Tone Work In the world 
 is produced with "Rubberine." 
 
 "The Practical Photographer, 
 "The Junior Photographer," 
 "Process Work and the 
 Printer," 
 
 •'The British Printer, 
 "The Art Printer," 
 " The Studio," 
 " In Town," 
 
 And numerous leading half-tone publications are printed with 
 
 " Rubberine." 
 
 SHr- This Composition and Rollers are used by the largest 
 users in the kingdom, and exclusively in the office of Mn. 
 Aldebman Alf. Cooke, of Leeds, the largest printing 
 works in Europe (380 machines). 
 
 Write for our 34 page Book of Testimonials. 
 
 Sole Agents for all Countries— 
 
 Messrs. Mander Brothers. 
 
 Works: Wolverhampton. 
 
 London Offices: 17, Gracechurch 
 Street, E.C. 
 
 Street, E.C. 
 Warehouse : 165, Oxford St., W. 
 Berlin : 29, Kurstrasse. 
 
 Paris : Rue de L'Entrepot. 
 Florence: 11, Piazza Santa Maria 
 
 Novella. 
 Vienna : Ungargasse, 15. 
 
 Rollers should be forwarded direct to Mr. C. H. Johnson, 
 Rubberine Works, Leeds, and consigned as Machinery. 
 
HALF-TONE 
 
ON THE AMERICAN BASIS. 
 
 J. H. DALLMEYER, LIMITED, 
 
 Manufacturing Opticians. 
 
 
 
 
 The Rapid Rectilinear, //8. 
 
 DALLMEYER 
 
 LENSES 
 
 FOR 
 
 - WORK. 
 
 Catalogue on Application. 
 
 The Stigmatic Patent, //4 & f/6. 
 
 
 
 
 Optical Manufactory : 
 
 25, Newman Street, Oxford Street, London, W. 
 
HALF-TONE 
 
 sfuftderide to it. 
 
 Read it, profit by it, contribute 
 to it, buy from its advertising 
 columns, get all your trade 
 friends to subscribe. 
 
 and 
 
 The Printer 
 
 For Photo-Mechanical Engravers and 
 High-class Printers. 
 
 Monthly, Threepence. 
 Specimen Copy free, 4^d. 
 
 Published by 
 
 Percy Lund & Co., Ltd., 
 
 The Country Press, Bradford; and 
 Memorial Hall, London, E.C. 
 
ON THE AMERICAN BASIS. 
 
 For the Half=Tone Process — 
 
 get your "supplies 
 from 
 
 Penrose & Co. 
 
 The Photo= Process Stores, 
 
 8a, Upper Baker Street, 
 
 ^ London, W.C. 
 
 Latest American Ideas 
 
 combined with 
 
 The Best English and Continental Experience. 
 
 Agents for 
 
 Levy & Wolfe Screens, 
 
 Western Engravers' Supply Co.'s Specialities, 
 Levy's Half-Tone Dark Slide, 
 American Copper and Fish Glue, 
 Routing and Trimming Machinery. 
 
 Manufacturers of 
 
 Special Cameras for the Half-Tone Process 
 
 (with Screen Adjustment), 
 Swing Copying Bases, 
 Patent Diaphragm System, 
 Prisms and Mirrors, 
 
 and many other up-to-date appliances. 
 
HALF-TONE 
 
 ON THE AMERICAN BASIS. 
 
 Established nearly 100 years. 
 © © 
 
 Tftander J3rother4 
 
 Makers of Fine Varnishes for 
 Letterpress and Lithographic 
 Inks. 
 
 Makers of Fine Colours 
 for All Trades. 
 
 Crimson and Scarlet Lakes, Pure Cochineal and 
 Madder Lakes, Exceedingly Pure Acid-Free 
 Chrome Yellows, Bronze and other Blues, Colours 
 with a Bronze Sheen when Printed, and of 
 
 Various Specialties for Artistic Printing. 
 
 Makers of Lithographic and Letterpress 
 
 Printing Inks 
 
 for various modern processes. 
 
 © © 
 
 Mander Brothers, London :— 17, Gracechurch St., E.C. 
 
 Gebruder Mander, Berlin : — 29, Kurstrasse. 
 
 Fratelli Mander, Florence : — 11, Piazza Santa Maria 
 
 Novella. 
 Paris :— Rue de [.'Entrepot, 3. 
 Vienna:— in, Ungargasse, 15.