^ r- Ua ^ https://archive.org/details/fewplainanswerstOOross A FEW PLAIN ANSWEES TO COMMON QUESTIONS REGARDING PHOTOGRAPHY. BY ROSS AND THOMSON, ^8I)otograp!)£rs to l^zx 90 prince’s street, Edinburgh. j— M.DCCC.LIII. EDINBURGH : PRINTED BY MaCPHERSON & SYME, 12 ST DAVID STREET. A, FEW PLAIN ANSWEES TO COMMON QUESTIONS REGARDING PHOTOGEAPHY. j Question. What is the meaning of the word Photograph ? | Answer. A picture taken by the action of light — Photos being the Greek word for light, and gra'phein to describe or draw. Q. Are there more than one kind of Photographic pictures ? A. There are several, but only two have been brought into j practical use, — the Daguerreotype, which has been used al- j most wholly for the taking of Portraits, — and the Talbotype,* W'hich has been chiefly applied to the taking of Landscapes. Q. How is a Daguerreotype likeness taken ? A. By light reflected from the sitter, and transmitted through an optical glass, called a lens, and received upon a prepared plate, inside of a darkened box (ordinarily termed a C amera - Obscura) . * Or Calotype. 4 PLAIN ANSWERS TO COMMON QUESTIONS I Q. By what means is the Daguerreotype plate prepared, I so that it will retain the image painted upon it ? i A. The surface of the plate, which is pure silver (plated I upon copper), being first highly polished, is coated with I the vapours of Iodine and Bromine, which impart to it the i property of being exceedingly sensitive to light ; so much so, ; . that the comparatively small portion of light which is reflected I from the sitter, even in a room, is sufficient in a few seconds j to impress the image. Of course the more direct and power- I ful the light that falls on the sitter, the more rapidly will the image be impressed. Q. Can the image thus formed be seen while the process is going on ? A. No: for although the picture is upon the metal, it is quite invisible till exposed to the vapour of mercury, which having great- attraction for silver, rests in beautiful and pro- portional gradation upon ail the parts where the iodine and bromine have been driven off by the light. Thus the mercury forms the lights of the picture, and the bare silver plate the shadows. Q. Does the mere action of light force the iodine and bro- mine away from the surface of the plate ? A. With a certain portion it does ; and it so neutralizes what remains, that the mercury adheres as well to the silver surface as if it were not there at all. A mercury box can be so made, that the whole of the deve- lopement may be seen going gradually on. Q. When taken from the mercury, is it finished ? A.' One other process remains. In its existing state, light would in some degree affect it. To prevent this, the iodine and' bromine are washed away, by means of hyposulphite of soda IN PHOTOGRAPHY. and a solution of gold poured on and burned into it. This is tech- nically called gilding, and, if properly done, not only improves the general appearance, but fixes permanently the picture. Q. Is it really permanently fixed ? ^ A. Yes ; it will last as long as it is kept properly glued up from the air, — not that the air wastes the picture away, but it tarnishes it exactly as it does any other kind of silver plate. Q. Are they true likenesses ? A. Yes ; truth is stamped upon them all. Yet some of them shew how disagreeable truth may, in some cases, be made to appear. The veriest tyro in painting, that ever tried his prentice hand upon the human face divine, probably never produced greater monstrosities than have occasionally been perpetrated by this art ; while, on the other hand, it has pro- duced gems as sweet as Raphaehever painted. No ideal Ma- donna and Child can surpass a really good Daguerreotype of a Young Mother and her Baby. In short, the good are very good, while the bad are very bad. Q. What is the cause of this difference, if every one who makes the art a profession uses the same kind of instrument and chemicals ? A. The difference arises from a variety of causes : — 1st, Because every Photographer has ideas wide apart from each other, of what constitutes excellence. What one man calls distinctness, another calls hardness ; softness with one is haziness with another. Agreeableness of expression is all and all with a few ; while a plate free of all markings of polishing bounds the ambition of many. But, 2dly, another and more important reason of the existing difference is, the placing of ^ We have Daguerreotypes, taken eleven years ago, as fresh as the day they were done. 6 PLAIN ANSWERS TO COMMON QUESTIONS both the sitter and the lens. If the lens be placed too high, the upper portion of the face will be too large in proportion to the under ; or, if too lov/, vice versa; in either case causing distor- tion. Besides all this, every Photographer’s room is lighted on the most opposite principles. If the light comes too much from one side, it makes the shadows too black ; if from the front, it makes the face fiat, for want of shadows, and is apt to spoil the eyes ; if lighted from the top alone, it makes the shadows under the eyes, nose, and lips, too long and dark, at the same time making the hair on the top of the head, although it should be black, perfectly white. Q. Will a proper adjustment of the lens alone prevent the hands being too large, as they often are ? A. Not as yet. Except the sitter keep them in a line with the face, they will still be too large ; or, if they were put fur- ther back than the head, they would be too small. The great improvement even now required in the Daguerreotype, is an in- crease of sensitiveness. Whenever this takes place, a lens of a different construction can be used, which will almost wholly overcome the enlargement of the near parts, and the dimi- nishing of the distant. Q. Does it give colours in true proportion to each other ? A. Not quite. Blue, for instance, in its photographic re- sults, comes out rather too light ; hence blue eyes, except they reflect something dark, are always too pale. Yellow, again, comes out too dark, which is the reason that fair hair, without proper management, appears of a deeper shade than it should be. Anything red or green likewise comes out a little too dark. White acts very quickly, so much so, that the white parts of a dress always look confused, from these being over- done long before the dark parts are done at all. Thus, if in- IN PHOTOGRAPHY. 7 stead of pure white, the lace, &c. of ladies’ dresses were slightly coloured, the whites in the picture would appear pure. Q. What colour of dress is best ? A. On the whole, decidedly dark. It may, however, be any colour ; but if the dress be too light, the face and hands will look dingy, Q. What kind of a day is best ? A. A clear day is necessary, but not sunshine, except per- haps for children, with whom great rapidity of execution is required. Q. Can thsee Pictures be taken with the real colours ? A. No, not yet ; though scientific persons think this pro- bable, and some approaches have been made to it ; but, in the meantime, they can be coloured by an artist, a process of I colouring having been adapted for the purpose, which mate- rially heightens the effect. Q. Why is it generally necessary to take more than one Picture ? A. Not altogether but mainly, that there may be a chance of getting one picture where the sitters have forgotten that I they were sitting for their portraits. When this is the case the expression is natural and not assumed. Q. Plow is a Talbotype likeness taken ? A. By exactly the same sort of instrument as the Daguerreo- type ; but, instead of metal, they are taken on glass, coated with a preparation of gun cotton and ether, called Collodion. This is the most recent improvement in Talbotype ; and, al- though far from being perfect, is well adapted for small pic- tures, even in its present condition. 8 PLAIN ANSWERS TO COMMON QUESTIONS Q. How is the picture or image impressed upon the Collo- dion ? A. The Collodion having combined with it a small pro- portion of iodide of potassium, is poured as evenly as pos- sible, upon the glass, and, when partly dry, is dipped into a solution of nitrate of silver, having thirty grains to the ounce of water. This is placed in the camera, in the ordinary frame, and in much the same time as the Daguerreotype the image will be impressed. Like it, it is also invisible at first. In- stead, however, of being developed with mercury, it is put into a bath of weak pyrogallic acid, with a little acetic acid added, when immediately it begins to appear, but exactly the reverse of what it should be, the black parts remaining light, and the white parts becoming dark. When fully developed, it is fixed by pouring hyposulphite of soda on the surface, which is again washed off with water ; and this finishes vvhat is called the negative proof. From this many copies can be taken, as mentioned in the answer to the next question. Q. How are these copies taken A. They are taken upon paper prepared for the purpose, first by being brushed over with a solution of common salt, ten or tw'clve grains to the ounce of water. This being dry, is again brushed or floated OTer with nitrate of silver, sixty grains to the ounce of water. Both being dry, the negative is laid down with its face upon the prepared side of the paper, :j®nd, by means of a board with screws, and a plate of thick glass, these are pressed closely together, and left either in sun- shine or clear daylight. The result is, that the light gradu- ally darkens those parts where the negative is light, while the dark portions prevent the light from penetrating through them, and they of course remain white on the paper, or com- IN PHOTOGKAPHY. 9 paratively white, according to the depth of tone of the nega- tive. ! Q. How is it known when a picture from the . negative is ^ sufficiently impressed on the paper ? A. The negative and the prepared paper can be wafered : together at two corners, and lifted up and examined ; but | practice soon teaches the requisite time without this, always | keeping in view that the picture should ffie allowed rather to be overdone, in order to make allowance for the effect of the | chemical agents v/hich are employed in fixing it. Q. V/hen printed, does it require fixing, as well as the : negative ? I A. Yes ; if not fixed, it would soon get all dark together-. After being washed in water, it is put into a bath of hyposul- phite of soda, wdiich takes up all the silver that has not been darkened by the light, leaving the dark parts v/hich form the picture unaffected. i Q. Does this entirely fix it ? | A, No ; it can be only termed half fixed in this state. It | cannot darken any more ; but if the h^^posulphite of soda is. ; not got quite out of the paper, it will, in a very short time, eat ; out the picture itself. The only way a complete fixing can be : effected, is by a simple, yet, when there are many to do, a very | laborious process, viz. by repeated v/ashings in hot and cold | water, till every particle of the size be dissolved out of the ! paper. Thus all. remains of h3^posulphite are carried away I with the size, and the fixing is now finished. The pictures ! should be dried with clean blotting paper, or a soft towel. | Q. Is the Talbotype in any way superior to the Daguerreo- type ? I A. In one thing only it is superior : it is better seen, not ! 10 PLAIN ANSWERS TO COMMON QUESTIONS having the metallic reflection which the silver plate still has I in a small degree. But again, it is not nearly so delicate and j ! soft ; it requires a stronger light for the process, and conse- ■ I quently makes the shadows so dark, that it is altogether as yet \ I unfit for a lady’s portrait, although it does very well for gen- I tlemen. Some such substance as paper, but having a far finer j texture, has yet to be discovered, before they can equal the I Daguerreotype in fineness. Q; Do they last as well as the Daguerreotype ? A. If carefully done, dark impressions will last well, pro- 1 vided they be kept from damp. | Q. Is there any other substance except Collodion upon j which Talbotype pictures are taken ? | A. Yes ; Albumen (the white of an egg), which is a better ! j material for landscapes, although it is not sensitive enough ; for the taking of portraits. ■ Q. How is the albumen prepared ? . 1 A. The white of eggs, having twelve drops of saturated iodide of potassium added to each egg, is beat up into a large j mass of froth, and allowed to stqnd for t^ or twelve hou^ j till it falls into a liquid. ! Q. How is this spread upon the glass ? A. By a very simple method, invented by an amateur.* It is exactly on the principle of a roasting-jack, the glass plate being hooked by two opposite corners with a piece of bent wire, to which is attached a worsted thread. The albumen is poured plentifully on the surface (which must be very clean), and when all is covered, the glass is turned gently over, and I 1 * Mr William 3I‘Craw, who we are glad to see has just received I from the Ro^al Society of Arts a Silver Medal, for an improved Ca- mera. aC^ /e ^6 zt' /H~^ ^ A-'X—- y^t^ M. 7^:zM^ ^ i IN PHOTOGRAPHY. 11 'made to revolve, at a moderate rate, before a clear fire. When the albumen begins to crack at the edges, it is withdrawn from the fire, when these minute cracks will,