y 
 
ON 
 
 THE MATERIALS USED 
 
 IN 
 
 PAINTING, 
 
 WITH A PEW REMARKS ON VARNISHING AND CLEANING 
 PICTURES. 
 
 BY 
 
 CHARLES MARTEL, 
 
 AUTHOR OF “THE PRINCIPLES OF COLOURING IN PAINTING, ETC.” 
 
 LONDON: 
 
 GEORGE ROWNEY AND COMPANY, 51 AND 52, RATHBONE PLACE. 
 
 1859. 
 
PRINTED 
 
 IHt 
 
 DERBY : 
 
 BY RICHARD KEENE, IRON GATE. 
 
 GETTY CENTER 
 LIBRARY 
 
CONTENTS 
 
 Par. 
 
 Introduction 1 — 5 
 
 What is a Paint P 6 — 13 
 
 Nomenclature of Colours ' 14 — 25 
 
 The Pigments 26 — 27 
 
 Blue. 
 
 Ultramarine — Ultramarine Ashes — Prussian Blue — Ant- 
 werp Blue — Yerditer — Cobalt Blue — Smalt — Indigo- 
 
 Intense Blue 28 — 47 
 
 Yellow. 
 
 Cadmium Yellow — Gamboge — Gallstone — Indian Yel- 
 low — Naples Yellow — Chrome Yellow — Orpiment — 
 
 King’s Yellow — Chromate of Zinc 48 — 59 
 
 The Ochres. 
 
 Yellow Ochre — Mars Yellow . 60 — 64 
 
 Red. 
 
 Carmine — Madder — Yermilion — Scarlet ...... 65 — 74 
 
 Violet and Purple. 
 
 Purple — Madder Purple — Burnt Carmine — Purple Lake 75 — 80 
 
 Green. 
 
 Chrome Green — Emerald Green — Terre Vert — Verdi- 
 gris — Sap Green — Malachite . . i 81 — 88 
 
 Orange. 
 
 Red Lead 89 — 92 
 
 Brown. 
 
 Umber — Terra di Sienna — Cologne Earth — Vandyck 
 
 Brown — Cappagh Brown — Bistre — Sepia- Asphaltum . 93 — 102 
 
CONTENTS, 
 
 White. Par. 
 
 White Lead — Zinc White 103 — 109 
 
 Black. 
 
 Blue Blaok — Ivory Black — Lamp Black — Indian Ink . 110 — 116 
 
 Grey. 
 
 Normal Grey — Coloured Greys — Mineral Grey .... 117 — 119 
 The Lakes. 
 
 Indian Lake — Yellow Lake — Mineral Lake .... 120 — 125 
 
 The Pinks. 
 
 Brown Pink 126 — 127 
 
 Vehicles and Mediums , 128 
 
 Oils. 
 
 Fixed Oils — Essential Oils — LinseedOil — Nut Oil — Poppy 
 
 Oil— Magilp 129—140 
 
 Drying 141 — 146 
 
 Dryers 147 — 175 
 
 VARNISH. 
 
 Oil and Spirit Varnishes * 176 — 190 
 
 The Resins. 
 
 Sandarac — Mastic — Copal — Amber — Lac 191 — 208 
 
 Solvents. 
 
 Turpentine — Alcohol — Linseed Oil . 209 — 212 
 
 Water Mediums. 
 
 Gum Water — Ox Gall ,, . ., . . . 213 — 215 
 
 Varnishing . 216 — 232 
 
 Picture Cleaning 233 — 244 
 
ON 
 
 THE MATERIALS USED 
 
 IN 
 
 PAINTING. 
 
 INTRODUCTION. 
 
 1. To the instructed observer, every picture displays the 
 extent of the artist’s knowledge of his art, and is also an 
 evidence of his proficiency or ignorance of any portion of it. 
 
 2. The Artist’s accuracy of drawing may be unimpeachable, 
 yet his knowledge of perspective or of chiaroscuro imperfect. 
 He may possess a knowledge of the harmony and contrast of 
 colours, but be ignorant of the nature and properties of the 
 pigments he employs to produce this harmony. Thus, his 
 proficiency in one part of his art may be neutralized by his 
 ignorance of another — his knowledge of harmony and contrast 
 may be defeated by injudicious mixtures of his pigments ; or 
 by misdirected experiments with vehicles, which, giving rise to 
 chemical changes in his paints, will tend to ensure the ultimate 
 destruction of his pictures, as the works of Reynolds, Hilton, 
 and Turner, sufficiently testify. 
 
6 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 3. The question is often asked, — how it happens that so 
 many pictures painted two, three, or even more centuries ago, 
 look fresher and purer than others painted within the last 
 twenty or thirty years. 
 
 4. This is a matter of the first importance to the artist. 
 For every picture that is worth painting, must also be worth 
 preserving ; therefore the artist should spare no effort to secure 
 his work from the ravages both of time and accident, as well 
 as from the spontaneous changes that arise from the use of 
 improper vehicles, or untried pigments. 
 
 5. Doubtless, every artist does his best to secure a good 
 result ; and if he fails, it is probably owing to the want of that 
 information concerning the Materials used in Painting, 
 which it is the design of this little book to furnish, viz. : a 
 knowledge of the materials of which a picture is composed, and 
 of those by which it is protected against time, accident, and 
 the noxious agents ever present in the atmosphere. These 
 materials are Pigments and their Vehicles, or Paints and 
 Varnishes. 
 
 6. The first question we have to consider is, 
 
 WHAT IS A PAINT ? 
 
 A Paint is a substance, — usually a coloured earth, or artificial 
 chemical product, called pigment — ground in some suitable 
 medium, such as oil, water, Ac., by which it can be spread on 
 the surface to be painted. 
 
 7. Pigments are obtained from the three kingdoms of 
 nature ; but by far the greater portion are derived from the 
 mineral kingdom, such are the Ochres, Vermilion, Ultramarine, 
 Ac. ; the vegetable kingdom supplies us with Indigo, Madder, 
 
ON TIIE MATERIALS USED IN PAINTING. 
 
 7 
 
 Gamboge, <fcc. ; the animal kingdom supplies us with Carmine, 
 Indian Yellow, Sepia, &c. 
 
 8. The artificial or chemical preparations are very numerous : 
 they include Prussian Blue, Naples Yellow, Chrome Green, 
 Zinc White, Cobalt, French Blue, the Mars series, the Lakes, 
 and many others. 
 
 9. The natural or crude pigments are prepared for the 
 artist’s use by calcining, washing, grinding, &lc. ; and, for oil 
 painting, are ground up in refined poppy or linseed oils ; when 
 applied to the canvas, the artist employs certain vehicles or 
 mediums, such as magilp, prepared copal, &c., to give the 
 requisite consistency to the paint. 
 
 10. From what has been said, it will be seen that Paint is 
 a very simple substance, consisting of the pigment and its 
 vehicle. The qualities desiderated in the latter are transparency, 
 freedom from colour, and the property of drying. 
 
 11. Linseed Oil, rendered drying, becomes converted 
 into a hard, tough, resinous substance, which suffers little 
 change by atmospheric agents ; these qualities eminently fit it 
 for a vehicle in oil-painting. 
 
 12. If the pigment and the vehicle are both of good quality, 
 and nothing is added to them that will destroy their integrity, 
 they are almost imperishable ; but when the artist, not content 
 to “ let well alone,” desires to improve what is already good 
 enough, and adds various nostrums to his paint, he thereby 
 increases the dangers to which such works are already but too 
 much exposed, without any compensating advantage. 
 
 13. Paint, composed only of oil and pigment, is, when hard, 
 insoluble in water and pure alcohol (spirits of wine,) but is 
 slowly acted upon by oil, and more rapidly by spirits of 
 
8 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 turpentine. This fact will be found of importance when we 
 come to consider the subject of picture cleaning. 
 
 NOMENCLATURE OF COLOURS. 
 
 14. What follows will be better understood if we define 
 certain terms employed when speaking of colours. 
 
 15. The colour of an object is that peculiar optical quality 
 all bodies possess of reflecting certain coloured rays, and 
 absorbing others. An object that reflects all the coloured rays 
 possesses no colour, but appears white; while a body that 
 absorbs all the coloured rays, appears black. 
 
 16. Ordinary-day light is termed white light. A ray of this 
 light, a sunbeam, when decomposed by a prism, or as we see 
 it in the rainbow, is found to consist of rays of six different 
 colours. Three of these, Blue, Red, and Yellow, are termed 
 primary colours, because they are the source from which all 
 other colours are derived, Mixed in pairs, as Blue with Red, 
 Blue with Yellow, Yellow with Red, — Violet, Green, and 
 Orange are produced, — these are termed secondaries. 
 
 17. The Primaries and the Secondaries are pure colours. 
 When a mixture consists of ail three primaries grey is produced, 
 which goes to break or tarnish the purity of the pure colours, 
 producing broken colours. 
 
 The term tertiary colour is too vague to be employed : 
 what are commonly called tertiary colours are coloured greys 
 or BROWNS. 
 
 18. For the pure colours there is a constant type in the 
 colours of the prismatic spectrum, which we always have in 
 view when speaking of colour in the abstract. 
 
 19. There are no constant types or standard for the so 
 
 ! 
 
ON THE MATERIALS USED IN PAINTING. 
 
 9 
 
 called tertiary colours. No two persons will exactly agree as 
 to the proper hue of an olive, russet, or citrine. 
 
 20. Pure white and black mixed, produce normal grey , 
 which varies in tone according to the preponderance of either 
 the black or the white. A primary or a secondary added to 
 normal grey produces a coloured grey, thus we have blue, red, 
 and yellow greys ; orange, green, and violet greys. 
 
 21. A normal colour is that colour taken at its greatest 
 intensity, without the addition of any other colour, or of white 
 which weakens it, or black which deepens it. 
 
 22. A tone of a colour signifies the normal colour mixed 
 with white or black in varying quantities, producing various 
 light and deep tones; this term is equivalent to lights and 
 shades. 
 
 23. A hue of a colour signifies a given colour mixed with 
 small portions of another colour, but not sufficient to change 
 its identity. Thus red may be mixed with various portions of 
 blue, but not in sufficient quantity to make it purple ; or with 
 yellow in various portions, but not sufficient to make it orange ; 
 then all these mixtures produce various hues of blue. We can, 
 however, take purple or green, and add blue or red to the one, 
 and blue or yellow to the other, and so produce various hues 
 of purple and of green. 
 
 24. It is only in the prismatic spectrum that Colour can 
 be seen apart from any material substance, and consequently 
 in a state of absolute purity. In attempting to represent these 
 colours by material pigments we shall find that carmine very 
 nearly approaches the prismatic red, as ultramarine and gamboge 
 do blue and yellow. Natural pigments supply better compound 
 colours than can usually be obtained by mixing pigments of 
 
10 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 simple colours, for this reason, that scarcely any pigment reflects 
 only one kind of rays. Thus ultramarine reflects, besides blue 
 rays, a small quantity of red rays, which gives it a violet tinge ; 
 if we mixed a yellow with this blue, the compound would con- 
 tain, besides green, a small portion of grey , produced by the 
 presence of the red, combining with equal portions of the blue 
 and yellow; the presence of this grey would impair the 
 brilliancy of the green, or break it, as much so as if we added 
 to a pure green a minute portion of grey or black pigment. 
 In like manner, Carmine, our purest red, contains a minute 
 portion of blue, as also does gamboge. 
 
 If the artist, in mixing pigments, observes the tendency of a 
 pigment to acquire another hue, and mixes with it only that 
 colour with which it is tinged, he will obtain a tolerably pure 
 compound. Thus in mixing blue and yellow for green, it will 
 be better to take a blue tinged with yellow, and a yellow tinged 
 with blue, than those pigments that contain red ; since pure 
 green consists only of blue and yellow, and the presence of red 
 must break or tarnish its purity by introducing grey. 
 
 I shall not repeat the nonsense usually found in books about 
 advancing and retiring, or hot and cold colours, nor endeavour 
 to represent by arbitrary figures the relative powers of colours, 
 by asserting that yellow is 3, red 5, or blue 8 ; such statements 
 are entirely devoid of meaning, and are uttered in complete 
 ignorance of the law of simultaneous contrast of colours, as 
 developed by M. E. Chevreul.* Vague and fantastic assertion 
 must give way before rational experiment and scientific proof. 
 
 * The principles of Harmony and Contrast of Colours , and their appli- 
 cations to the Arts, translated from the Trench of M. E. Chevreul, by 
 Charles Martel. 2nd Edition. Longman and Co., London. 1855. 
 
OX THE MATERIALS USED IN PAINTING. 
 
 11 
 
 25. In refutation of the statements alluded to, it is only 
 necessary to remark that whenever two colours are placed in 
 proximity, they no longer appear of the same hue as when 
 viewed separately, but they mutually modify each other, not 
 only in colour , but in tone. By juxtaposition, a blue may 
 be made to appear greenish or violet; a yellow , orange or 
 greenish ; and a red , scarlet or crimson ; a light colour may be 
 made to appear lighter or deeper, and so with a dark colour ; 
 and as we seldom have to deal with isolated colours, it is 
 evident that all that can be said of the power of a colour is 
 relative, being entirely dependent upon the colour or colours 
 with which it is associated. 
 
 THE PIGMENTS. 
 
 26. With two or three exceptions, the pigments derived 
 from the mineral kingdom, such as ultramarine, the ochres, and 
 bitumens, are the most durable; this is especially the case 
 with those containing iron and copper. But the pigments 
 derived from the vegetable and animal kingdoms, such as 
 madder and carmine, leave little to be desired on the score of 
 permanency, while the purity and brilliancy of their colours 
 render them an important acquisition to the palette ; as it would 
 be impossible to supply their place from the resources of the 
 mineral kingdom. 
 
 27. Pigments are opaque or transparent. The opaque 
 are employed for representing light, for which their solidity 
 and opacity eminently fit them ; as the more these qualities are 
 present in a pigment, the more light it reflects. Por shadows 
 and glazing, the transparent pigments are employed. 
 
 * 
 
12 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 28. The permanence or durability of pigments is in some 
 measure conditional ; but as the consideration of this question 
 involves much chemical knowledge, we can in this place only 
 briefly indicate some of the more striking results of the action 
 of light, air, and mixture upon pigments. 
 
 The action of light upon coloured bodies has, at present, 
 been only imperfectly examined. Generally it is supposed 
 to have a bleaching property. It is well known, however, that 
 pictures kept for a long time in a dark room, or when turned 
 to the wall, lose much of their brilliancy, and recover it again 
 when exposed to sunshine or daylight. 
 
 Pure air cannot be considered to have an injurious effect 
 upon paint, although the moisture always present in it may. 
 But in cities and towns the atmosphere is contaminated with 
 the sulphurous emanations from sewers, and from the combus- 
 tion of coal and coal-gas. This sulphuretted gas attacks white, 
 or carbonate of lead, and converts it into the sulphide, which 
 is black. 
 
 Bouvier, in his Manual for Painters and Amateurs, says, 
 “ It is much to be wished that painters had more knowledge of 
 the chemistry of colours than they usually possess.” But this 
 knowledge cannot well be acquired without studying the 
 elements of general chemistry. When the artist understands 
 what is meant by chemical decomposition, he will recognise 
 how important it is that he should fully understand the chemical 
 constituents of his pigments when he is about to mix them 
 together. A very large proportion of the pigments prepared 
 for artists’ use are chemical compounds in which the respective 
 constituents are united in fixed and definite proportions, which 
 determine the colour of the pigment. The force that holds 
 
ON THE MATERIALS USED IN PAINTING. 
 
 13 
 
 these respective constituents together is frequently so slight 
 that the balance is easily disturbed by mixture, the pigment 
 decomposed, and consequently changed in colour. 
 
 This knowledge will teach the artist that it is safer to mix 
 such pigments together as are alike in chemical composition, 
 and also to resort to mixing as seldom as possible, only when 
 the desired effect cannot possibly be obtained without. The 
 majority of pigments are sufficiently permanent for ordinary 
 use; when employed alone, and even in mixture, the oil or 
 varnish medium protects them greatly from chemical decom- 
 position. In water-colour painting, change in composition 
 from mixture of pigments is much more rapid and certain. 
 
 In the following descriptions of pigments, the chemical 
 nature of the pigments is indicated so far as was compatible 
 with the scope of this little book. 
 
 Dahlia Carmine is a fine pigment prepared from cochineal, 
 more permanent than carmine ; it is used in water colours, 
 affording brilliant purple transparent tones of great value in 
 flower painting. 
 
 Permanent Crimson Lake. A fine transparent red pigment 
 prepared from cochineal, tolerably permanent, and very useful 
 in oil painting. 
 
 Violet Carmine. A very beautiful pigment, transparent 
 and permanent, useful in oil and water colours. 
 
 BLUE. 
 
 28. Blue is one of the three primary colours. Mixed with 
 yellow in various proportions, it yields various hues of green ; 
 in like manner, mixed with red, it furnishes various hues of 
 violet, purple, <fcc. 
 
14 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 2D. Amongst our pigments, the nearest that approaches the 
 blue of the prismatic spectrum, is ultramarine, and some choice 
 samples of blue carbonate of copper. There is a slight tinge 
 of red in both these pigments, but it is only evident by com- 
 parison with pure blue. 
 
 30. The complementary colour of blue is orange, the 
 secondary composed of the other two primaries, red and 
 yellow. 
 
 3 1 . The principal blue pigments are ultramarine, native and 
 artificial, cobalt, smalt, Prussian blue, and indigo. 
 
 32. Ultramarine. This pigment has long stood at the head 
 of those with which the artist’s palette is supplied ; to this pre- 
 eminence its beauty and durability fully entitle it. It may be 
 employed in all kinds of painting, and be mixed with all other 
 pigments without decomposing them. By artificial light, 
 ultramarine appears grey. 
 
 33. Ultramarine is obtained from the mineral lazulite or 
 lapis lazuli, found in the granitic regions of Persia, China, and 
 other parts of the world, but in very small quantities. It is 
 probably a volcanic product, as it resists the action of fire. 
 
 34. The scarcity, and consequent high price, of native 
 Ultramarine has excited the ingenuity of chemists to produce 
 artificially a pigment that should be fully equal to supply its 
 place. Thirty years ago, only the native pigment was known ; 
 but since that date we have been supplied with the artificial 
 product. The price of the former was eight guineas an ounce, 
 that of the latter varies, according to its quality, from one 
 shilling to twenty-five shillings the pound. 
 
 35. Analysis of native Ultramarine shows that it consists 
 of a combination of silicate of alumina, of silicate of soda, and 
 
ON THE MATERIALS USED IN PAINTING. 
 
 15 
 
 
 of sulphuret of sodium, in variable proportions ; the colour is 
 due to the presence of a minute quantity of iron. 
 
 36. Formerly, most of the artificial Ultramarine came 
 from France, but Germany now supplies us with an excellent 
 pigment. 
 
 37. Artificial Ultramarine comes to us under the form of a 
 brilliant blue powder. There are a great many qualities ; the 
 inferior are used in dyeing and paper staining, they have a 
 violet hue. The finer qualities are reserved for artists’ use. 
 'Every exhibition contains pictures utterly ruined by the 
 presence of this blue used in a crude state for skies. 
 
 38. This pigment is permanent in the air, and under the 
 sun’s rays ; it is insoluble in water, alcohol, ether, the fixed, 
 and volatile oils. It is quickly decomposed by acids. Sub- 
 mitted to a strong heat, it fuses into a colourless or very 
 slightly coloured glass ; if this calcination takes place in the 
 open air, it acquires a green hue. 
 
 39. The process of manufacturing artificial Ultramarine is 
 one of the most interesting in the arts ; but the details belong 
 properly to a treatise on Applied Chemistry. 
 
 40. Ultramarine Ashes. In the preparation of native 
 ultramarine, a blue grey pigment is separated, to which the 
 name of Ultramarine Ashes is given. It is useful to the 
 landscape painter in supplying him with a delicate permanent 
 pigment for skies, and for shadows in flesh tints. 
 
 41. Prussian Blue. A very intense blue pigment, slightly 
 tinged with green. It is a compound of prussic acid and 
 iron. Previous to its discovery in 1720, indigo was the only 
 blue pigment used in the arts. 
 
 Prussian blue varies much in quality, according to its mode 
 
16 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 of preparation. That manufactured at Berlin contains alumina ; 
 but English and French Prussian blue generally contain 
 alumina only as an adulteration. 
 
 When of good quality, this pigment is transparent and 
 tolerably permanent. It is insipid to the taste, inodorous, 
 insoluble in water, alcohol, oil, and diluted acids, (except 
 muriatic and oxalic,) but is decomposed by several metals, such 
 as tin and iron, by concentrated acids, alkalis, bin-oxide of 
 mercury, and most of the metallic oxides. Heated strongly 
 in the open air it burns like tinder, leaving a reddish brown* 
 residue; if kept from contact of air, it yields a fine black 
 pigment. 
 
 A solution of Prussian blue in oxalic acid forms the well known 
 blue writing fluid. 
 
 Prussian blue is more valued in water-colours than in oil- 
 painting. It is useful to strengthen the tones of other blues, 
 but its employment always requires consideration. It must 
 not be mixed with vermilion, nor with cadmium, or mars 
 yellow, if permanency is sought. It dries quickly, and if 
 employed alone, no objection can be made to its use. 
 
 42. Antwerp Blue. This pigment only differs from 
 Prussian blue in containing alumina, and sometimes carbonate 
 of magnesia and carbonate of zinc. Its tone varies accordingly. 
 It is considered to be as permanent as Prussian blue, and to 
 have more solidity. 
 
 43. Verditer. Is a carbonate of copper and lime, obtained 
 by a peculiar mode of preparation. It is a sky-blue pigment, 
 opaque, but not permanent, and is apt to turn green in oils. 
 
 44. Cobalt Blue. Of late years this pigment has been 
 prepared in a state of great purity and beauty ; it would in 
 
ON THE MATERIALS USED IN PAINTING. 
 
 17 
 
 ; many cases supersede French blue, had it not the objection of 
 i appearing violet by artificial light. It is transparent, durable, 
 and mixes very well with other pigments in oil-painting. Its 
 1 tone depends upon the quantity of alumina present in its 
 , ! composition. 
 
 t 45. Smalt. This pigment owes its colour to the presence 
 
 i ! of cobalt ; it is a kind of frit or coloured glass, consisting of 
 f | silicate of potash, oxide of iron, nickel, lime, magnesia, alumina, 
 
 1 1 &c. Its tone depends on the relative proportions of silicate of 
 
 i' potash and cobalt in the compound. It is of an intense 
 : brilliant colour, transparent and permanent ; its hue is violet. 
 
 Useful for draperies and in flower-painting in water colours, 
 l 46. Indigo. Indigo belongs to the class of pigments called 
 
 lakes, by which term is understood, such vegetable colouring 
 • I principles as, being deficient in body, require the addition of 
 , j an alkaline, or earthy base, such as lime, alumina, &c., to 
 t supply that body. Indigo has a lime base; it is of a deep 
 s | blue colour, tinged with red, which gives it a violet hue. It is 
 f without taste or odour, and adheres to the tongue like pipe-clay. 
 
 Ordinary solvents have but little action upon it ; it is insoluble 
 i in water, cold alcohol, ether, the fixed and volatile oils, diluted 
 3 acids, and alkalis. Concentrated boiling alcohol dissolves a 
 small quantity. Exposed to the action of heat in the open air 
 
 0 it melts at 554° and is partially decomposed, rising in purple 
 vapours. In fuming sulphuric acid it dissolves almost entirely, 
 
 1 forming Saxon blue, blue carmine, and other pigments. 
 
 t) Indigo is more useful in water colours than in oil ; in the 
 latter it is apt to become green or black ; but in water colours 
 ti it is a most valuable pigment — transparent, permanent, and 
 a | mixes well with other pigments. 
 
18 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 47. Intense Blue. This is a preparation of Indigo, but 
 of a brighter tone. It must be carefully applied to the paper, 
 since it attacks it so strongly, as to penetrate it completely. 
 
 YELLOW. 
 
 48. Yellow is a primary colour. Mixed with blue in 
 different proportions it yields various hues of Green ; with red 
 it produces various hues of orange. It is the most luminous 
 of colours. 
 
 The complementary colour of yellow is the secondary violet, 
 which is composed of the other two primaries, blue and red. 
 
 Among pigments, gamboge more nearly represents the yellow 
 of the prismatic spectrum than any other pigment. It has, 
 however, a slight, but scarcely perceptible tinge of blue. 
 
 49. The yellow pigments are numerous, but a desideratum 
 still exists in a transparent yellow adapted to oil painting ; a 
 pigment equivalent to gamboge in water colours. 
 
 Among the most important yellow pigments are cadmium 
 yellow, chrome yellows, the ochres, gamboge, Naples yellow. 
 
 50. Cadmium Yellow. This is a comparatively recent 
 addition to the palette. It is a remarkably brilliant colour, 
 but has no transparency. It is composed of sulphur and 
 cadmium, and therefore cannot be employed with pigments 
 that have a lead base, such as white lead ; but with oxide of 
 zinc, or zinc-white, it forms durable compounds. With blue 
 pigments it forms rich greens. Much of the Naples yellow 
 now sold consists of cadmium yellow and white lead, but this 
 cannot be considered any improvement, as the objection to 
 Naples yellow is its containing a portion of lead, which blackens 
 when exposed to air containing sulphuretted hydrogen. 
 
ON THE MATERIALS USED IN PAINTING. 19 
 
 51. Gamboge. Gamboge is a gum-resin, consisting of from 
 75 to 80 per cent, of resin, and 20 to 25 per cent, of gum. 
 Its characteristics are as follows : ether dissolves about four- 
 fifths, leaving the gum as residue. Alcohol dissolves a large 
 portion. It is insoluble in water, with which it forms an 
 emulsion. Its colouring properties are very great; it will 
 impart its colour to 10,000 times its weight of alcohol or water. 
 Camphene dissolves the resinous portion of gamboge, leaving 
 the gum untouched. 
 
 Gamboge is much employed in water-colours, being a trans- 
 parent pigment, of a fine bright yellow colour, permanent, and 
 mixes well with other pigments. In oil it is deficient in body, 
 owing to the presence of the gum, but there is no doubt it can 
 be made available, and that desideratum, a transparent yellow 
 for oil-painting, obtained. 
 
 52. Yellow Carmine, or Gallstone. Gallstone is obtained 
 in such small quantities for the purposes of commerce that it is 
 necessary to substitute some other substance as a pigment. 
 Yellow carmine, obtained from Persian berries, precipitated by 
 alumina, yields a transparent fugitive pigment equal in every 
 respect to gallstone. 
 
 53. Indian Yellow. The origin of this pigment has been 
 much disputed. According to Erdman, who appears to be the 
 best authority, it is the urinary deposit of the camel which has 
 been fed on the fruit of the mangostana onagifer, the colour- 
 ing principle of which is communicated to the urine, and 
 afterwards deposited by it. This deposit is collected dried, 
 and forms an article of commerce. 
 
 Cold water dissolves a very small quantity of Indian yellow ; 
 alcohol and ether have no action upon it; by analysis it is 
 
20 
 
 ON TIIE MATERIALS USED IN PAINTING. 
 
 shown to consist of a combination of magnesia, with a peculiar 
 organic acid to which the name of purreic acid is given ; small 
 quantities of carbonates of potash and lime, and of chloride of 
 potassium, are also found in it. Its high price tempts fraudulent 
 dealers to adulterate it with other yellow pigments, as chrome 
 yellow, &c. But as pure Indian yellow burns like tinder, 
 leaving scarcely any residue, the adulteration may be easily 
 detected. 
 
 Indian yellow is of a very rich golden yellow colour, of good 
 body, semi-transparent, and permanent. It dries slowly in oil. 
 
 54, Naples Yellow. This pigment has enjoyed a high 
 degree of popularity, more so, we think, than it is entitled to. 
 Its composition was for a long time unknown, but analysis 
 shows that it is the result of a combination of antimonic acid, 
 with oxide of lead in various proportions, The original Naples 
 yellow was probably a volcanic product. 
 
 Naples yellow is an opaque pigment, of a very fine yellow 
 colour ; it is easily decomposed by iron, therefore the palette- 
 knife with which it is mixed must be of ivory or of horn, and 
 it should be ground on a porphyry slab ; on stone it acquires a 
 disagreeable greenish hue. 
 
 Much of the . Naples yellow now sold is cadmium yellow, 
 mixed with white lead ; zinc white would be preferable. 
 
 55, Chrome Yellow. The metal chromium is a very 
 important colouring material, As chromic acid it unites with 
 several bases, forming chromates. Chrome yellow is a chromate 
 of lead; there are many hues of chrome yellow dependant 
 upon the proportions of acid and base, and the addition of the 
 chromates of lime and barytes, and of sulphate of lead. The 
 inferior qualities contain alumina, winch it is supposed renders 
 them more permanent. 
 
ON THE MATERIALS USED IN PAINTING. 
 
 21 
 
 Chrome Yellow is an opaque pigment, useful both in oil and 
 in water colours, better employed alone, or with White, than 
 with other pigments such as Prussian Blue, or Vermilion. 
 
 No less than six different Chrome Yellows are met with in 
 commerce, varying in hue from pale primrose to Orange 
 Vermilion. 
 
 56. Chromic acid mixed with strontian forms Lemon 
 Yellow ; and with zinc, various yellow pigments not yet 
 named. 
 
 57. Orpiment. Sulphur and acid unite in various pro- 
 portions, forming sulpliuret of arsenic. Two native pigments 
 are found, one of which is realgar , or bisulphuret of arsenic, 
 and the other orpiment , which is tri-sulphuret ; the first is of 
 tm orange-red colour, the other is golden yellow. The quantity 
 found in nature is too small to supply the wants of the arts, 
 therefore, these pigments are prepared artificially on a large 
 scale as King’s Yellow. 
 
 Native Orpiment is a pigment of metallic lustre, inodorous, 
 insoluble in water, alcohol, ether, and the oils. It is unaffected 
 by most of the acids, but nitric acid decomposes it. It is 
 fusible and volatile without decomposition in closed vessels. 
 It is not a durable pigment, and cannot be recommended for 
 use, and it is. very poisonous. 
 
 58. Patent Yellow or Mineral Yellow is a chloride of 
 lead, obtained by decomposing litharge by common salt, 
 (chloride of sodium) and exposing the resulting chloride to a 
 great heat. There are various other processes of manufacture, 
 but the result is the same, namely, a compound of protochloride 
 of lead mixed with variable proportions of oxide of lead. 
 
 Patent Yellow is a brilliant light yellow pigment, opaque, 
 
22 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 and durable, when employed alone; exposed to sulphurous 
 exhalations, it blackens slightly, but much less so than most 
 other pigments with a lead base. 
 
 59. Chromate of Zinc. Many experiments have been 
 made to substitue the oxide of zinc for the oxide of lead in all 
 the chemical preparations of that metal employed as pigments. 
 Chromate of zinc, prepared under certain conditions, advan- 
 tageously replaces chromate of lead (chrome yellow.) As its 
 name indicates, chromate of zinc is a compound of chromic 
 acid and oxide of zinc. It is a very beautiful yellow pigment, 
 opaque, permanent, and mixes well with other pigments. 
 
 THE OCHRES. 
 
 60. The Ochres form a class of pigments valuable for their 
 permanency and general utility in painting. Their composition 
 is very variable, but they may be considered as true chemical 
 combinations of clay and oxide of iron, resembling lakes. The 
 combination of these two oxides is so complete, that diluted 
 acids have no effect upon them ; it is only by heat and con- 
 centrated acids that they are decomposed. These qualities 
 show that they are eminently fitted for pigments. 
 
 The native Ochres are yellow and red. The yellow is most 
 abundant. By calcination, the yellow ochres become red, 
 (Light Red.) Native red ochre is known as red chalk. Cologne 
 Earth is a brown ochre; Indian Red and Venetian Red are 
 native ochres. 
 
 61. Oxford Ochre is a very useful pigment in landscape- 
 painting, both in oil and water-colours, affording fine green 
 mixtures of good body, and permanent. 
 
 The Mars pigments are artificial ochres. 
 
 
ON THE MATERIALS USED IN PAINTING. 
 
 23 
 
 62. Mars Yellow. The pigments to which the word mars 
 [ (iron) is prefixed, are artificial ochres, prepared with a view of 
 
 obtaining colours possessing the good qualities of native ochres, 
 but without the earthy tint that is sometimes objectionable to 
 their use. 
 
 The mars pigments are prepared by precipitating certain 
 soluble salts of iron by means of the alkalies, or alkaline earths, 
 such as potash, soda, lime, and alumina. Their preparation is 
 an exceedingly difficult and delicate operation which only long 
 I practice can overcome. 
 
 63. Mars Yellow is a pigment of a very fine colour, 
 semi-transparent, and quite permanent, useful both in oil and 
 
 |i watef-colours. 
 
 64. By calcining Mars Yellow we obtain, (according to the 
 degree of heat applied, and by other means kept secret by 
 manufacturers,) orange, brown , red , and violet mars. Pigments 
 of great durability, but expensive. 
 
 BED. 
 
 65. Red is a primary colour. Mixed with Blue in different 
 proportions it yields Violet, Purple, Lilac, and their hues; 
 mixed with yellow it produces Orange. 
 
 66. The complementary of Red is the secondary Green, 
 
 ; composed of the two other primaries, Blue and Yellow. 
 
 67. The red pigments are of animal, vegetable, and mineral 
 origin. Carmine is of animal origin, being obtained from the 
 cochineal insect. It supplies us with the red that approaches 
 nearest to that of the prismatic spectrum. Prom the vegetable 
 kingdom we obtain the valuable series of Madder pigments, 
 and the mineral kingdom supplies us with Vermilion, the red 
 ochres, and other useful pigments. 
 
24 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 68. Carmine. Among red pigments Carmine holds the 
 first place, as in its normal strength it approaches as nearly to 
 the prismatic red as Ultramarine does to prismatic blue. The 
 light tones of Carmine are. bluer than the normal colour. 
 
 The mode of preparing Carmine was kept secret for many 
 years, it is now well known to be obtained from the cochineal 
 insect, by an extremely delicate process which is only successful 
 in very experienced hands. 
 
 The dried body of the cochineal insect yields to water 
 and alcohol a beautiful red colouring matter, to which Mr. 
 De la Rue has given the name of carminic acid. This colouring 
 matter may be precipitated by alumina and oxide of tin, 
 forming the pigment known as Carmine. 
 
 Carmine is certainly the most beautiful red pigment we 
 possess. In commerce we meet a greater variety of qualities 
 of it than of any other pigment. It is opaque, but very 
 permanent, but mixes well with other pigments. 
 
 69. Madder supplies the artist with several valuable pig- 
 ments, as Madder Lake, Rose Madder, Madder Brown. Purple 
 Madder, Madder Carmine. They are distinguished for the 
 purity of their hues, their transparency, and durability, in 
 mixing well with other pigments, and in being equally useful 
 in oil and water colours. 
 
 7 0. The Madder pigments are lakes. The colouring matter, 
 alizarine, is separated by chemical process from the roots of 
 the rubia tindorum, and precipitated on an alumina base. 
 Various qualities appear in commerce, the differences in which 
 are due to the quality of the madder-root, the place of its 
 growth, and the mode of its preparation. 
 
 71. < By the action of sulphuric acid upon madder roots, 
 
ON THE MATERIALS USED IN PAINTING. 25 
 
 ( 
 
 even those from which all the colouring matter appears to be 
 extracted, or spent madder , a colouring material, garancin , is 
 obtained, which possesses a greater tinctorial power than that 
 first extracted ; this is Madder Carmine. 
 
 72. Madder Carmine from the beauty of its colour and 
 durability may be advantageously substituted for cochineal 
 carmine. 
 
 73. Vermilion. This pigment is a compound of sulphur 
 and mercury, called red sulphuret of mercury. It is found 
 native in various parts of the world, particularly in the mines 
 of Spain and Peru. It is also prepared artificially in Prance, 
 Germany, Holland, China, and England. 
 
 Vermilion is a dense heavy substance of a blood-red colour, 
 without taste or smell, insoluble in water, alcohol, ether and 
 the oils. It is readily decomposed by heat, and when adul- 
 terated is liable to blacken in the atmosphere unless protected 
 by varnish. With certain pigments, such as White Lead, 
 Prussian Blue, &c., it cannot be mixed without risk of speedily 
 changing. It is useful both in oil and water-colours. 
 
 74. Scarlet. This pigment, recently introduced info the 
 arts, is a compound of iodine and mercury, (the protiodide of 
 mercury ;) as both its constituents are volatile, it may be sup- 
 posed that the colour is very evanescent. Its durability 
 depends upon the care with which it is prepared. 
 
 Iodine Scarlet is a bright coloured pigment, of good body, 
 opaque, and very useful in flower painting. There is no other 
 pigment that approaches it in brilliancy. 
 
 VIOLET AND PURPLE. 
 
 75. Violet is a secondary colour resulting from the mixture 
 of blue and red rays in equal strength and proportion. In 
 
26 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 purple the blue predominates over the red. Hyacinth and 
 lilac are hues of violet. 
 
 7 6. Violet, a secondary, is complementary to the primary 
 yellow. Those who entertain the idea of tertiary colours, say 
 that Violet mixed with Green yields Olive (Blue Grey,) and 
 that mixed with Orange it yields Russet (Red Grey.) Such 
 is a fanciful theoretical result ; in practice, the mixture of pig- 
 ments of these colours produces only mud. 
 
 77. Purple. This colour can be readily obtained by 
 mixture of suitable red and blue pigments, such as contain 
 little or no yellow in their hues. The Purple pigments are 
 Madder Purple, Burnt Carmine, Purple Lake, Mars Violet, 
 Dahlia, and Violet Carmine. 
 
 78. Madder Purple, as its name implies, is a pigment 
 obtained from Madder of great strength and body, and rich 
 colour. It is transparent, durable, and mixes well with other 
 pigments. It is equally good in oil and water colours, and 
 dries and glazes well. 
 
 79. Burnt Carmine. This is carmine of cochineal torre- 
 fied until it assumes a deep rich purple colour; a pigment 
 useful in water colour painting. 
 
 80. Purple Lake. This pigment is obtained from 
 cochineal, and in all its essential qualities resembles the other 
 lakes. Its colour is violet rather than purple. 
 
 Madderine Lake. Chromate of copper (Marron Rougeatre.) 
 Chromate of silver is purple red; chromate of mercury is 
 violet red. 
 
 Dahlia and Violet Carmines are both preparations from 
 cochineal. They are tolerably permanent ; are very brilliant 
 colours, and useful in painting flowers or drapery. 
 
ON THE MATERIALS USED IN PAINTING. 
 
 27 
 
 GREEN. 
 
 81. GiIeen is a secondary colour, composed of Blue and 
 Yellow rays, its hue varying with the relative proportions of 
 each, thus we have yellow-greens and blue-greens. 
 
 The complementary of Green is Red ; the primary that does 
 not enter into the composition of the secondary, green. Mixed 
 with orange it produces (theoretically) the so-called tertiary, 
 Olive (Yellow Grey.) Most of the Green colours met with in 
 nature are Green- Greys, i. e., contain a small proportion of red, 
 which deepens their tone and alters their hue. ' 
 
 82. Green may be obtained by mixture of blue and yellow 
 pigments ; it varies in hue according to the respective qualities 
 of the pfimaries. Prussian Blue and Indigo, with Gamboge and 
 Burnt Sienna, are the most useful greens in water colours, to 
 which may be added, on the yellow side, Yellow Lake, Italian 
 Pink, Brown Pink, &c. 
 
 Most of the green pigments owe their colour to the presence 
 of copper, in the state of carbonate. 
 
 83. Chrome Green. This pigment is a sesqui-oxide of 
 chrome, which varies in hue according to the mode of its 
 preparation. It is a fine, cool, deep green, very durable, and 
 is much employed in enamel painting. Its high price limits 
 its use. There is an Emerald green of great beauty and 
 permanency, prepared from the oxide of chrome by a secret 
 process. It is very costly. Chrome green is insoluble in 
 water and the acids. 
 
 84. Emerald Green. The pigment usually sold under 
 this name is not a chrome green as its name would seem to 
 imply, but a copper green, consisting of carbonate of copper 
 with lime or alumina. It is opaque and durable, but dries 
 
28 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 slowly In oil ; its colour is a very bright, vivid green. Another 
 kind of Emerald Green consists of arsenic and copper, (the 
 arseniate of copper.) It is a very brilliant blueish green, 
 opaque and permanent. Its high price limits its use in the 
 arts. By the French it is called Paul Veronese Green , but for 
 what reason it is not easy to determine. 
 
 85. Terra Vert, called also Veronese Green is a native 
 earth found near Verona, also in Hungary, France, and other 
 countries; that obtained from Verona is the best. Its colour 
 would lead us to suppose that it contains copper, but analysis 
 fails to discover any. A sample examined for the purpose of 
 detecting copper, showed that it consists of about fifty per cent 
 of silica, in combination with alumina, magnesia, soda, and 
 about twenty per cent, of protoxide of iron, to which, and not 
 to copper, it doubtless owes its colour. 
 
 Terra Vert is a valuable pigment; especially useful in land- 
 scape and marine pieces. It is opaque and quite permanent. 
 When burnt it it yields Verona Brown. 
 
 86. Verdigris is a basic acetate of copper. As met with 
 in commerce, it varies ‘in hue, from pure to blueish green. It 
 is a bright green pigment, almost insoluble in water, transparent 
 in oil, and permanent as a glazing pigment. 
 
 87. Sap Green is a lake, obtained from the colouring 
 matter of the buckthorn united with a lime or alumina base. 
 It is not adapted for oil painting, but is useful in water colours. 
 Its colour is grass-green, but cannot be pronounced permanent. 
 
 88. Malachite Green. This beautiful green pigment 
 when native, is a carbonate of copper, found in the mountains 
 of Hungary and Siberia. It is opaque, of a delicate palish 
 green colour, and tolerably permanent. 
 
ON TEE MATERIALS USED IN PAINTING. 
 
 29 
 
 The scarcity qf the native pigment has led to the pro- 
 duction of several artificial pigments to supply its place in 
 ordinary painting, either by imitating its chemical composition, 
 or by mixing other ingredients. Some of these are carbonates, 
 others are arseniates of copper. 
 
 ORANGE. 
 
 89. Orange is a secondary colour, resulting from the 
 mixture of red and yellow rays. Its complementary is Blue , 
 the primary which is absent from its composition. Mixed 
 with Violet it (theoretically) produces Russet or Red Grey. 
 
 Orange ranks next to yellow as a luminous colour. 
 
 90. The principal Orange pigments are Red-Lead, Mars 
 Orange, Orange Vermilion, Orange Chrome, and Red Orpi- 
 ment. Some .samples of Cadmium yellow possess a deep 
 Orange hue. 
 
 91. Orange Vermilion. This is the lighter portion of 
 crude Vermilion, which is separated when the latter is mixed 
 with water ; the orange portion being the lightest, occupies 
 the upper portion of the pigment deposited by the water. It 
 is permanent, and mixes well with most other pigments. 
 Some specimens of Orange Vermilion are mixtures of Vermilion 
 and Chrome Yellow. 
 
 92. Red Lead, or Minium is a mixture of the protoxide 
 and binoxide of lead. It forms a pigment of a bright orange 
 colour, much used in the arts, but has the objection of blacken- 
 ing in sulphurous vapours. It is opaque, but cannot be mixed 
 with other pigments, except those that contain lead as a base. 
 
 BROWN. 
 
 93. Brown is a very indefinite term for a colour. Theoreti- 
 
30 
 
 ON THE MATERIALS TJSED IN PAINTING. 
 
 cally, browns are Orange Greys , that is, they are combinations 
 of the three primary colours, with red and yellow, or orange, 
 in excess. The various hues of brown must therefore depend 
 upon the proportions of each of these two primaries present in 
 a pigment. 
 
 94. Brown pigments are supplied by nature of a much 
 better quality than can be obtained by mixture of the primary 
 colours. Most of them owe their colour to the presence of 
 iron in various states of oxidation, which in great measure 
 ensures their permanency. Some, such as Bitumen and Van- 
 dyke Brown are of the nature of coal, changed by the action of 
 heat, or by slow natural decomposition. 
 
 95. Umber. Although this pigment derives its name from 
 Ombria, one of the Roman provinces, from whence it was 
 originally obtained, that now met with in commerce comes from 
 the isle of Cyprus, and is known as Turkey Umber. It con- 
 sists of about fifty per cent, of hydrated oxide of iron, and 
 twenty per cent, of oxide of manganese mixed with flint and 
 clay; it is employed in the natural state; when burnt it 
 acquires a reddish brown hue. 
 
 This pigment is seldom employed alone. It mixes well with 
 other colouring materials, is a good drier, and very permanent. 
 
 Boiled with raw linseed oil, in renders it siccative by the 
 action of the oxide of manganese it contains. 
 
 96. Terra di Sienna. This pigment is found in the 
 environs of Sienna, a city in the grand duchy of Tuscany. In 
 its natural state it is of a yellow colour, mixed with grey; 
 when burnt it assumes a reddish orange colour ; it is much 
 esteemed in painting,' both in oil and water colours, being 
 transparent and permanent, and mixes well with other pig- 
 
ON THE 2vIATERIALS USED IX PAINTING. 
 
 31 
 
 ments. In composition it is analogous to Umber, but contains 
 less oxide of manganese. 
 
 97. Yandyck Brown, Cologne Earth. This is a sub- 
 stance intermediate wood and coal, known as lignite or brown 
 coal, found at Bruhl, near Cologne, on the Rhine. It is called 
 ferruginous pulverulent lignite; in commerce it is known as 
 Cologne or Cassel earth, and sometimes Cologne Umber, but 
 it has no resemblance in its composition with Umber. 
 
 Cologne Earth is a very fine brown pigment, used both in 
 oil and water colours, transparent and permanent. 
 
 98. Cappagh Brown is a peat or bog-earth, coloured with 
 manganese ; it derives its name from the place, near Cork where 
 it is found. It is a deep, transparent brown pigment, which 
 dries well, and mixes well with other pigments without injury. 
 
 99. Bistre is a brown pigment obtained from the root of 
 certain woods, particularly that of the beech tree. It is much 
 employed in water colours, for drawings like those of Indian 
 ink and sepia. It is transparent and durable. 
 
 100. Sepia. This pigment is obtained from a shell fish, 
 common in the Mediterranean and Adriatic Seas, and the At- 
 lantic Ocean. It is contained in a membrane near the heart 
 of the fish, filled with a blackish brown fluid, from which by 
 drying the pigment is prepared. In commerce, it appears 
 when prepared, as a dark brow or nearly black impalpable 
 powder, insoluble in water and in alcohol ; it dissolves par- 
 tially in ether ; the caustic alkalies dissolve it without altera- 
 tion ; diluted acids have no action upon it. 
 
 The colour of Sepia is a deep rich warm brown, affording a 
 variety of agreeable tones. It is transparent and permanent, 
 and of great value to the water colour painter. 
 
32 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 101 . Asphaltum or Bitumen is a natural product found 
 floating on the surface of the Dead Sea, and in other countries. 
 Its origin is undetermined, it appears to be a volcanic product, 
 and is supposed to be produced by the melting of coal under 
 strong pressure. 
 
 As it occurs in commerce, Bitumen resembles in its external 
 qualities, pitch ; it is solid, brittle, transparent, black with a 
 tinge of brown, and has a bituminous odour when rubbed or 
 melted. It is very inflammable, and burns with much smoke. 
 It is insoluble in .water, soluble in turpentine, the fixed and 
 essential oils. It is of a fine transparent brown colour, and 
 quite permanent. It is very useful in oil painting for glazing, 
 and if ground in drying oil stands well. It dries slowly. As- 
 phaltum enters into the composition of certain varnishes, as 
 japan, and Brunswick black. 
 
 There are a great many varieties of Bitumen, the properties 
 of which vary from the description here given. There is also 
 a factitious kind, a product obtained from the gas-works, but 
 this is not fit for artist’s use, as it never dries. 
 
 102. Madderine Brown. This pigment, of recent intro- 
 duction, is a sub-chromate of copper, of very fine red marone 
 or brown colour, opaque, and permanent ; very useful in oil 
 painting. Its hue differs according to the method by which it 
 is prepared. 
 
 WHITE. 
 
 103 . Theoretically, White is the union of all colours, but 
 as pigments of colours as pure as those of the prismatic spec- 
 trum do not exist, the mixture of pigments of primary or 
 secondary colours produces not white, but grey or black. A 
 ray of white light when decomposed by the prismatic spectrum 
 
ON THE MATERIALS USED IN PAINTING. 
 
 33 
 
 is resolved into six distinct pure colours, and these may be re- 
 united by a convex-lens, and the ray of light re-produced. 
 
 104. The opposite , or complementary of white is black. 
 White bodies reflect all or nearly all the rays of light that fall 
 upon their surface. 
 
 105. Mixed with coloured pigments they yield the various 
 light tones of the respective colours. With black pigments 
 they form numerous tones of grey. 
 
 106. White pigments represent light, for which their 
 density and "opacity eminently fit them. 
 
 107. In associating coloured objects, the primary colours 
 gain in brilliancy by the juxtaposition of white, but light blue 
 and rose red form the most agreeable assortments with white ; 
 dark blue and red produce too strong a contrast to be agree- 
 able. 
 
 108. White-lead. This pigment is a carbonate of lead. 
 It is known by more aliases than any other pigment used. It 
 is Ceruse, Flake White, Cremnitz White, etc., these names 
 are determined by the place or mode of its preparation. One 
 enjoys great celebrity until another is produced, supposed to 
 be superior, which for a time, supersedes it. 
 
 In chemical composition they are all identical, the difference 
 in their hue arises from the method of preparation. 
 
 White-Lead is a dense opaque pigment, largely employed in 
 oil-painting, for grounds and in mixing with coloured pigments 
 to produce their various light tones. It is inodorous, insipid, 
 insoluble in water, soluble in acids with effervescence arising 
 from the liberation of carbonic acid gas. Exposed to heat, 
 White-Lead becomes oxidised, first into massicot , which is yel- 
 low ; if the heat is continued, more oxygen is absorbed, and the 
 
34 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 white-lead becomes lithurge, and finally red-lead or minium. 
 
 The chief, and perhaps only objection to White-Lead is, 
 that the sulphuretted hydrogen almost always present in the 
 atmosphere blackens if, as do certain pigments containing 
 sulphur. This chemical change is retarded or entirely pre- 
 vented when the paint is covered with varnish. 
 
 White-Lead possesses strong siccative properties; in this 
 respect it is superior to zinc-white, but the deficiency of the 
 latter in drying is overcome by the use of suitable dryers. 
 
 Whatever objections may lie against the use of White-Lead, 
 it has obtained so strong a hold upon the preference of the 
 artist, that it is scarcely probable it will be driven from the 
 field by the rivalry of Zinc- White. Chemically speaking, it is 
 inferior in durability to Zinc- White, yet White-Lead of good 
 quality is found to stand as well as need be, if judiciously 
 employed. 
 
 ZINC WHITE. 
 
 109. The introduction of oxide of zinc as a substitute for 
 White-Lead is one of the most interesting events in the annals of 
 art. As a pigment, it possesses all the qualities for which 
 White-Lead is prized, without any of those which are objection- 
 able. White-Lead cannot be mixed with many pigments with- 
 out suffering decomposition. It is quickly acted upon by 
 sulphuretted hydrogen, (evolved wherever human, beings con- 
 gregate, and frequently from gas-lights) which turns it grey or 
 black. Besides, it is very poisonous. None of these objections 
 lie against Zinc- White. Erom the great improvements recently 
 made in the processes of its manufacture its density is greatly 
 increased, while its covering power is greater, weight for weight, 
 than that of White-Lead. Experiments show that one pound of 
 
ON THE MATERIALS USED IN PAINTING. 
 
 35 
 
 
 Zinc- White covers as mubh surface as sixteen and a half ounces 
 of White-Lead. 
 
 Zinc -white is insoluble in water, ether, alcohol, and the oils, 
 both volatile and fixed, but the acids of moderate strength 
 decompose it. It is unalterable by heat. Hydrosulphuric 
 acid and the alkaline sulphurets form with it a white sulphur et, 
 which does not blacken. It is opaque, permanent, and mixes 
 well with other pigments. 
 
 Efforts are being made to produce various coloured pigments 
 in which zinc shall take the place of lead as a base. 
 
 It must be evident that the vehicle for Zinc- White should not 
 be the ordinary drying oil prepared with litharge ; as that 
 dryer being an oxide of lead, would impart to the zinc-white 
 the objectionable qualities possessed by White-Lead. A drying 
 oil is prepared expressly as a medium for Zinc- White, which is 
 equally adapted for other pigments. 
 
 BLACKS. 
 
 110. Black- pigments are Carbons or Charcoals^ of greater 
 or lesser purity, derived from animal and vegetable substances. 
 Pure Carbon is probably of a pure black, but the presence of 
 earthy matters in the substance from which the pigment is 
 obtained, imparts to it a grey or brown hue. These foreign 
 matters are the salts of lime, magnesia, soda, &c. 
 
 111. Black is very useful in painting, both by itself and 
 mixed with* white to form Normal-grey, of various tones. Be- 
 sides black-pigments, black is produced whenever pigments of 
 the three primary colours are mixed together in suitable pro- 
 portions, or when a secondary is mixed with its opposite or 
 complementary primary. 
 
36 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 112. Blue-black is a vegetable black, obtained by heating 
 vine twigs, or the kernels of peaches, apricots, &c., in a closed 
 vessel until they are converted into Charcoal. It is a very 
 fine black and yields with white pigments fine pearly greys. 
 
 113. Ivory-black is an animal-black, obtained from the 
 chips or turnings left by the ivory-turner. When it is really 
 obtained from this source, it possesses a fine rich tint, and 
 produces with white, good warm greys. It dries slowly. 
 Sometimes bone-black is substituted for it. 
 
 114. Lamp Black is a soot obtained by burning, with 
 slight access of air, certain resinous substances, oils, &c. It 
 is a very dense, opaque, pure black. A very fine black is 
 obtained from the soot of coal-gas. 
 
 115. Most of the Lamp-Blacks contain empyreumatic resins, 
 which give them a brown hue, and prevent their mixing with 
 water. To fit them for water colour painting the Lamp-Black 
 has to be heated to redness in closed vessels, or the resins 
 dissolved out by alcohol. 
 
 116. Lydian In*k. Much ingenious speculation has been 
 bestowed upon the source of this pigment, which brought from 
 China, could not for a long time be imitated with success, but 
 at the present day we need not be under any obligation to the 
 Chinese for a pigment which can be made at home of as good 
 quality as theirs. 
 
 GREY. 
 
 117. Normal-grey is produced by the mixture of pure 
 Black and White, yielding various tones of pure grey, accord- 
 ing as the White or Black predominates. It is also produced 
 by the mixture of the three primary colours, or by a colour 
 with its opposite or complementary colour, as in the case of 
 
f 
 
 ON THE MATERIALS USED IN PAINTING. 37 
 
 black. Normal-grey inay be cosidered as diluted black. As 
 most of our pigments contain two of the three primary colours, 
 when mixed with each other a small quantity of grey is pro- 
 duced, which tarnishes or breaks the purity of the mixture. 
 
 118. Coloured Greys are Normal grey, coloured with a 
 primary or secondary colour. They are produced when we 
 mix the three primaries in unequal strength and proportions, 
 so that one or two of them predominate. If we mix green and 
 violet we obtain a blue-grey ; if we mix orange and violet we 
 obtain a red-grey ; if orange and green a yellow-grey. 
 
 119. Mineral Grey is obtained from slate, which is finely 
 levigated, for artists’ use in oil-painting. There are two pig- 
 ments of this same material, differing in hue, but not in quality. 
 They are opaque, and quite permanent. 
 
 THE LAKES. 
 
 120. The differently coloured lakes , the nature of which 
 we will endeavour to describe, are supposed to have been 
 invented by the Dutch. 
 
 Most of the colouring principles obtained from the vegetable 
 kingdom possess the property, when they are suspended or 
 dissolved in water, of being precipitated by metallic oxides, 
 with which they combine, and form insoluble compounds, 
 known in the arts by the name of lakes. Thus we have 
 Yellow, Crimson, and Purple lakes. The power of affinity 
 which unites these colouring principles to the metallic oxides 
 is very great; by some chemists they are supposed to form 
 true chemical combinations. Whatever the nature of these 
 compounds may be, it is enough for the artist to know that 
 
38 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 they furnish him with a very useful series of pigments, which 
 at the present day he could scarcely do without. 
 
 121. The Lakes have always alumina for a base; some- 
 times, however, this consists of the oxides of lead and tin, of 
 lime and magnesia. The base determines the colour of the 
 pigment. Thus Yellow berries yield a deep yellow with 
 alumina, and a yellowish brown with alkaline carbonates. 
 
 122. Alumina has a peculiar affinity for animal and 
 vegetable colouring matters, and constitutes one of the best 
 mordants of the dyer. For the artists’ uses, the simple 
 colouring matter of cochineal, madder, etc., would be unavail- 
 able unless they were combined with some material to give 
 them body, and the substances that serve the dyer as mor- 
 dants, — alumina, oxide of tin, and chalk, are well adapted for 
 the purpose the artists’ colourman has in view. 
 
 123. Indian Lake. This is supposed to be the parent of 
 of all the lake pigments. From lac, familiarly known as shell- 
 lac, a dye-stuff is obtained known in commerce as lac-dye, a 
 colouring matter extensively employed in dyeing and calico 
 printing. Indian Lake is this colouring matter precipitated 
 from its solution by alum. It is inferior in brilliancy to 
 Cochineal, but appears to be more durable. It is a purple 
 red, transparent,' and mixes well with other pigments. In its 
 drying properties it resembles the other lakes, which, when 
 badly prepared and kept long ground in oil, assume a gelatinous 
 consistence, become livery as it is called, from the resemblance 
 they present to the liver of animals. 
 
 124. Yellow -Lake. This pigment is the colouring 
 { principle of Persian berries united to an earthy base. It is of 
 
 a greenish yellow hue, useful in mixing greens for landscape 
 
ON THE MATERIALS USED IN PAINTING. 
 
 39 
 
 painting in water colours. It is not so durable as most other 
 yellow pigments. 
 
 125. Mineral Lake. This is a valuable pigment used in 
 porcelain painting, which is deserving the attention of the 
 artist. It is a compound of oxide of chrome, lime, and 
 binoxide of tin ; its colour is that of the peach blossom, per- 
 manent, and is a valuable substitute for vegetable lakes in 
 obtaining a good lilac colour. 
 
 THE PINKS. 
 
 126. Under this anomalous title is included a class of 
 pigments which resemble the lakes, in deriving their colouring 
 material from French or Persian berries, but they have as a 
 base carbonate of lime (whiting) instead of alumina. They are 
 considered less permanent than the Lakes. 
 
 127. Brown Pink is obtained from French or Yellow 
 berries ( Rhumnus infedorius) grown in large quantities at 
 Avignon. 
 
 Italian Pink is the colouring matter of Persian berries, 
 nearly identical with French berries of a brighter yellow colour. 
 
 VEHICLES AND MEDIUMS. 
 
 128. The vehicle or medium most extensively employed 
 in oil painting is linseed oil ; poppy oil and walnut oil are also 
 used with pigments of delicate colours, which the deep hue of 
 linseed oil might injure. Copal and Amber varnishes, and a 
 mixture of drying oil and a mastic or copal varnish (magilp) are 
 used as Vehicles. 
 
40 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 OILS. 
 
 129. Oils are obtained from the animal and vegetable 
 kingdoms ; they are either fixed or volatile. 
 
 130. Fixed Oils. The fixed oils are either greasy or 
 drying oils; of the greasy oils some are fluid at ordinary 
 temperatures, others are solid, as tallow, butter, etc. They 
 are insoluble in water, slightly soluble in alcohol, but dissolve 
 largely in ether and in turpentine. They give a permanent 
 greasy stain to paper, and cannot be distilled without decom- 
 position. They absorb oxygen from the atmosphere with 
 more or less rapidity ; if slowly and in small quantity, the oil 
 becomes rancid, but does not alter its appearance 
 
 Others, absorbing larger quantities of oxygen thicken ; and 
 if spread in a thin layer or coat become solid, and resemble 
 resins ; such oils are termed drying oils ; linseed, poppy, and 
 walnut oils are of this kind. 
 
 131. Linseed Oil. This oil is extracted from the seeds 
 of the flax plant, ( linum usitatissimum.) If obtained by simple 
 pressure, without the aid of heat, it is called cold-drawn linseed 
 oil. It is of a deep yellow or brownish colour, with a dis- 
 agreeable smell and taste. It is soluble in ether and alcohol,* 
 and turpentine, When spread in a thin coat it dries into a 
 hard, tough, transparent varnish, a property which is increased 
 by boiling the oil alone, and still more by the addition of 
 certain metallic oxides. 
 
 132. The colour of linseed oil — considered as an objection 
 to its uses in oil painting— may be removed by the agency of 
 
 * Linseed oil dissolves in five parts of boiling alcohol, in forty parts of 
 cold alcohol, and in two parts of ether. 
 
ON THE MATERIALS USED IN PAINTING. 
 
 41 
 
 light. Exposed to the sun’s rays for an indefinite length of 
 time its colour becomes paler. 
 
 133. Besides its great use as a vehicle in oil painting, 
 linseed oil is employed as a solvent of the hard resins, copal 
 and amber, in the manufacture of varnishes. 
 
 134. Nut Oil. Large quantities of oil are obtained in 
 France from ripe walnuts. By simple pressure, without the 
 aid of heat, a sweet limpid oil is obtained, almost colourless, 
 which dries slowly when exposed to the air. Treated with 
 metallic oxides it becomes, like linseed oil, more siccative. It 
 Is employed for delicate pigments. 
 
 135. Poppy Oil. This oil is extracted from the seeds of 
 the poppy. , 'Et is of a pale yellowish white colour, less viscid, 
 but more drying than linseed or nut oils ; it may be rendered 
 more siecative by the same means as are employed with them. 
 
 136. Magilp. By this name is known a mixture of mastic 
 varnish and drying linseed oil, which gelatinizes and forms a 
 vehicle which prevents the pigments flowing on the canvas. 
 Some doubts are expressed as to the policy of using it, but 
 while most condemn its use almost everyone does use it. 
 
 137. Essential Oils. The essential or volatile oils differ 
 in all their properties from the fixed oils, as much so as two 
 things called by the same name can possibly differ. 
 
 They are generally secreted by plants ; they do not saponify 
 by the addition of alkalies ; they can be distilled without de- 
 composition ; they give to paper a greasy stain, which, however, 
 disappears as the oil evaporates. By exposure to the air they 
 absorb oxygen, and become resinous. They mix in all 
 proportions with fixed oils, dissolve freely in alcohol and ether, 
 
42 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 are insoluble in water. As solvents of the resins they are of 
 great value. 
 
 138. Turpentine may be taken as a type of an essential 
 oil ; and it is the one most employed in painting. 
 
 139. When a volatile is added to a fixed oil, it dilutes it ; 
 and a coat of the mixture leaves, on drying, a thinner coat 
 than when it is employed alone, in consequence of the evapo- 
 ration of the essential oil. 
 
 1 40. Oil of Spike and Oil of Rosemary, essential oils, are 
 used for dissolving copal and other resins. 
 
 DRYING. 
 
 141. It is necessary to explain what is meant by the term 
 drying when applied to oil or oil-paint, as it is a misnomer. 
 
 142. Usually, by drying we understand that a body parts 
 with its moisture, and becomes so much lighter in weight in 
 proportion to the quantity of water evaporated. 
 
 143. But oil in drying, or becoming hard and solid, loses 
 nothing in weight, on the contrary, it becomes heavier in 
 consequence of absorbing oxygen. 
 
 144. This fact can be easily proved by covering a piece of 
 glass with a coat of oil-paint, weighing it while wet, and after- 
 wards when dry ; it will be found to have increased in weight. 
 
 145. That the drying is due to the absorption of oxygen 
 is proved by the oil becoming solid more rapidly in a vessel 
 filled with oxygen gas, than in the atmosphere. In a vessel 
 filled with carbonic acid gas the oil will not become solid at 
 all. 
 
 146. Some substances retard the drying of oils ; these are 
 the black pigments, the lakes, bituminous earths, bitumens, &c. 
 
ON THE MATERIALS USED IN PAINTING. 
 
 43 
 
 DRYERS. 
 
 147. Dryers are the substances added to oils to increase 
 their siccative property. The most important are the pro- 
 toxide of lead, and the peroxide of manganese. Sulphate of 
 zinc ( white vitriol ,) acetate of lead (sugar of lead,) sub-car- 
 bonate of zinc, are also substances employed as dryers; but the 
 pigments themselves, such as white-lead and zinc-white , and 
 heat, greatly increase the natural siccative property of drying 
 oils. 
 
 The influence of these agents on the oil may be thus made 
 evident. 
 
 148. Influence of air. Pure cold-drawn linseed oil spread 
 upon glass takes about seventeen days to become hard or dry. 
 
 149. If, however, the oil is previously exposed to the air 
 
 in an open vessel for forty or fifty days, it becomes more 
 siccative, and will dry in about four days. It also loses 
 its dark brown colour, becoming as pale as nut or poppy oil, 
 and can be used with the most delicate pigments. • 
 
 150. Influence of heat. Boiling or baking as it is some- 
 times called, causes linseed oil to become siccative, but the 
 duration of this boiling has a remarkable effect upon the result. 
 
 151. If the oil is boiled for three hours without the addition 
 of a dryer , it dries in about half the time it takes to dry when 
 unboiled ; but if the boiling be prolonged to five hours, the oil 
 dries much slower than when boiled only three hours. 
 
 152. If the oil is first boiled, without addition, for five 
 hours, then boiled again three hours, it takes longer to dry 
 than if it had not been boiled at all, as much as forty days. 
 
 153. If the oil is first boiled five hours, then boiled again 
 
44 ON THE MATERIALS USED IN PAINTING. 
 
 eight hours, it loses its siccative property entirely ; it becomes 
 viscid, and remains so at the expiration of fifty days. 
 
 154. The common opinion is, that as boiling causes linseed 
 oil to become siccative, the more it is boiled, the more that 
 quality is increased ; but such is not the case. 
 
 155. Influence of Litharge. If linseed oil is boiled three 
 hours with about ten per cent, of protoxide of lead ( litharge ) it 
 becomes very siccative, and dries in about two days ; but if 
 the oil is first boiled without addition, for five hours, then 
 boiled with ten per cent, of litharge for three hours, it takes 
 four days to dry. 
 
 156. Influence of per-oxide of manganese. A very sicca- 
 tive oil is obtained by boiling pure oil for five hours, and then 
 boiling it eight hours with per-oxide of manganese. 
 
 157. When boiling the oil is objectionable, a good 
 drying oil may be obtained by exposing the linseed oil mixed 
 with ten per cent, of per-oxide of manganese to a temperature 
 of 160° for eight hours, 
 
 158. A remarkable fact is, that the power of the litharge 
 and manganese in causing oil to become siccative is greatly 
 increased after they have been previously employed for the 
 purpose. 
 
 159. No less singular is the following fact. The drying 
 property of pure linseed oil is represented by 1.985; of 
 manganese oil by 4.719. It would be supposed that if we 
 added to pure linseed oil, one-fourth of its bulk of oil boiled 
 with manganese, the drying properties would be represented 
 by 6.704, whereas, in fact, it is 30.827, or more than four and 
 a half times as much. This fact can be turned to account. 
 Manganesed oil is of a very dark colour, and cannot be used 
 
ON THE MATERIALS USED IN PAINTING. 
 
 45 
 
 with many pigments, but we can take cold-drawn linseed oil, 
 and, by boiling it with a fourth part of the manganised oil, 
 obtain a highly siccative oil but very slightly coloured. 
 
 160. Influence of sub -carbonate of zinc. The addition of 
 sub-carbonate of zinc to linseed oil is attended with a curious 
 result; the mixture dries very quickly, but instead of being 
 opaque, like the mixture of oxide of zinc with linseed oil, it is 
 semi-transparent, and even transparent. Probably this fact 
 may be turned to account in glazing. 
 
 161. Influence of sugar of lead. Sugar of lead ( acetate o f 
 lead,) added to pure linseed oil, increases its siccative property. 
 The advantage of adding it to oil already rendered drying is 
 not very evident. 
 
 162. Influence of Sulphate of Zinc. White vitriol (or white 
 copperas as it is sometimes called,) is a sulphate of zinc. It is 
 used as a drier. When calcined, added to zinc-white ground 
 in linseed oil, it accelerates the drying of the paint. 
 
 163. Influence of Pigments. Since the introduction of 
 zinc-white as a substitute for white-lead has become general, it 
 will be useful to enquire what difference exists between the 
 siccative properties of these two metals. 
 
 164. A coat of paint prepared with pure linseed oil, mixed 
 with white-lead in the proportions of 10 parts by weight of the 
 first with 18 parts of the second, was spread on a canvas 
 primed with white-lead ground in drying oil. 
 
 The 1st coat dried in 4 days. 
 
46 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 165. Another paint was prepared with 10 parts of pure 
 linseed oil ground with 7 parts of zinc white (oxide of zinc.) 
 The 1st coat dried in 18 days. 
 
 „ 2nd „ 15 „ 
 
 ,, 3rd ,, 5 ,, 
 
 38 days. 
 
 It is evident then that zinc white cannot be used without 
 the addition of a dryer. 
 
 166. Influence of Turpentine. Turpentine added to pure 
 linseed oil increases its siccative property. 
 
 167. Pure linseed oil and turpentine kept in corked bottles 
 forty-four days, then mixed, when spread on glass dried in 
 twenty-two hours. 
 
 168. The same materials exposed to the air forty-four 
 days, dried in fifteen days, when spread on glass. 
 
 169. But if the oil and turpentine were first mixed, then 
 kept forty-four days in a corked bottle, the mixture spread on 
 glass dried in sixteen days. If the mixture was exposed forty- 
 four days to the air, then spread on glass, it dried in nine days 
 and a half. 
 
 170. Influence of Zinc white. If a mixture of oil and 
 Zinc white dries in eleven days, the addition of Turpentine 
 causes it to dry in six days. The mixture of oil and turpentine 
 kept forty-four days, which dried in sixteen days, when zinc 
 white was mixed with it, dried in seven days and a half. 
 
 171. Zinc white was added to the same mixture which had 
 been exposed forty-four days to the air, and which dried in 
 nine days and a half, — the paint dried in five days and a half. 
 
 172. Paint may be kept fresh any length of time if it is kept 
 
ON THE MATERIALS USED IN PAINTING. 
 
 47 
 
 under water, provided the pellicle that forms on its surface is 
 not broken, and the water renewed as it evaporates. The 
 water protects the paint from the action of oxygen. 
 
 173. Influence of temperature. Drying is greatly accel- 
 erated by heat. A picture will dry much quicker in a warm 
 and dry atmosphere than in one that is cold and damp. 
 
 174. Influence of the ground. The surface upon which a 
 drying-oil or paint is applied exercises a great influence upon 
 the drying. If the ground is absorbent, a much thinner surface 
 of oil and paint is left to be acted upon by the atmosphere, 
 and the drying is more speedily accomplished. 
 
 175. Linseed oil spread on sheets of copper, brass, zinc, 
 and iron dried in about two days ; on lead it dried in six hours. 
 On planed deal it dried in seventeen days, on poplar in twenty- 
 three, and on oak in thirty-four days. 
 
 VARNISH. 
 
 176. A Varnish is a resin dissolved in a suitable medium, 
 as oil, turpentine, or alcohol, forming a transparent fluid, 
 which, when applied to the surface of a picture, serves to 
 protect it against accident, and the destructive action of 
 noxious agents present in the atmosphere. 
 
 177. The essential qualities of a good varnish are 
 transparency, durability, and hardness ; that it should be free 
 from colour, and dry quickly. These qualities must necessarily 
 depend upon the nature of the resin employed, and also, 
 although in an inferior degree upon the solvent, which may be 
 either volatile or fixed. 
 
48 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 178. The resins commonly employed for picture varnishes 
 are Mastic, Copal, Amber, Sandarac, and White Lac. 
 
 179. The solvents are Turpentine, forming Turpentine 
 Varnishes; Alcohol, forming Spirit Varnishes ; Linseed Oil, 
 forming Oil Varnishes. 
 
 180. Under ordinary conditions Mastic resin is soluble in 
 Turpentine and in Alcohol. 
 
 181. Sandarac is soluble in Alcohol, but insoluble in 
 Turpentine. 
 
 182. Copal and Amber are soluble in boiling Linseed oil, 
 but insoluble in Alcohol and Turpentine. 
 
 183. The properties and qualities of a varnish depending 
 mainly on the Resin, an examination of that substance will 
 enable us to judge its fitness for the purpose. 
 
 184. One of the chief qualities of a Varnish is hardness; 
 it offers the security of great durability, and is less easy of 
 removal from the surface to which it is applied. 
 
 185. We find that the softer and more brittle the resin, 
 the more readily soluble it is, and the more liable to injury. 
 
 186. If we examine specimens of the resins employed in 
 making picture- varnishes, we find that in respect to brittleness 
 and Softness they take rank as follows : — Sandarac, Mastic, 
 Copal, and Amber. 
 
 187. Sandarac is therefore the weakest, most brittle, and 
 readily soluble; while Copal and Amber are the toughest, 
 hardest, and most difficult to dissolve. 
 
 188. The solvent , however, exercises some influence on the 
 result of a varnish. 
 
 If the solvent is volatile , like turpentine and alcohol, when 
 the varnish is spread and dries, the solvent evaporates, leaving 
 
ON THE MATERIALS USED IN PAINTING. 
 
 49 
 
 the resin exactly in the state it was before it became varnish. 
 Such varnishes dry as quickly as they are applied. 
 
 189. But if the solvent be a fixed oil, then all the varnish* 
 both oil and resin, remains on the canvas, and in addition to 
 the resin, there is the hardened oil, which, by absorbing 
 oxygen, has also become a tough resinous substance. 
 
 190. It is evident then, that an oil-varnish possesses many 
 advantages over a spirit or turpentine varnish, in being harder 
 and tougher, and less easily removable from the surface of a 
 picture by the action of solvents. When an oil-vamish is 
 applied to the painted surface of a picture it softens the paint 
 while drying, and ultimately combines with it. The spirit 
 varnishes are used chiefly for ornaments, toys, etc. ; the 
 turpentine and oil varnishes for pictures, etc. 
 
 THE BE SINS. 
 
 191. In the language of commerce the Besins are called 
 indiscriminately, Gums and Gum-resins, but in the language 
 of science each of these names belongs to substances possessed 
 of very different properties. 
 
 192. Gum is a substance that softens or dissolves in water* 
 but which will not dissolve in alcohol, or in the fixed and 
 essential oils. The solution of Gum in water forms mucilage, 
 and Gum Arabic is a type of this class of substances, or of 
 Gums properly so called. A solution of Gum Arabic serves as 
 a varnish in water-colour. 
 
 193. Besins are fusible and combustible substances, in- 
 soluble in water, but soluble, some in the fixed oils, some in 
 \he volatile oils, others in alcohol and in ether. 
 
50 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 Mastic, Copal, Sandarac, and Amber are true resins. 
 
 194. Gum-Resins are chiefly used in medicine ; they par- 
 take of the qualities both of Gums and Resins, being partially 
 or imperfectly soluble both in water and in alcohol, and the 
 essential oils. Gamboge is a gum-resin. 
 
 195. Most of the resins appear to be compounds of two or 
 more resins, as is shown by their partial solubility in one 
 menstrum, and complete solubility in another. 
 
 196. Sandarac. This resin is obtained from a Juniper 
 tree, (the Callitris quadrivalvis,) and is the one usually 
 employed for making spirit varnish. It appears to consist of 
 a mixture of three kinds of resin, one soluble in ordinary 
 alcohol; one insoluble in alcohol; and another soluble in 
 alcohol of 90 per cent. 
 
 Sandarac is met with in commerce in the shape of tears of a 
 yellowish-white hue, transparent, brittle, and inodorous ; it is 
 less soluble in turpentine than in alcohol, and not at all soluble 
 in water. 
 
 The brittleness of this resin requires that some ingredient 
 should be put into the varnish that will give it more tenacity. 
 Turpentine, by containing a small quantity of resin, added to 
 the spirit in which the Sandarac is dissolved, is found to 
 produce the desired result. 
 
 197. Mastic. This resin is produced by the pistachio, 
 lentiscus, a tree growing in the Grecian Archipelago, par- 
 ticularly the Isle of Ohio. The best quality is in small oblong 
 rounded tears, of a pale yellow colour, transparent, and brittle. 
 It breaks with a bright glassy fracture; when chewed, it 
 becomes soft and ductile, with a mild and agreeable taste an 
 odour. 
 
ON THE MATERIALS USED IN PAINTING. 
 
 51 
 
 When heated, it melts ; at a higher temperature it burns, 
 diffusing an agreeable odour. Like other resins, it is insoluble 
 in water, but dissolves completely in ether. It is partially 
 soluble in cold, and completely soluble in hot alcohol. Dis- 
 solved in Turpentine, it forms the ordinary picture varnish. 
 
 198. Mastic Varnish is usually made as follows: — lOlbs. 
 of picked Mastic, 2 gallons of Turpentine, put into a tin can 
 with 2 lbs. of glass, bruised to the size of barley; agitate the 
 whole until the resin is dissolved; then strain it through 
 fine muslin. It should be kept six or nine months before it is 
 used. 
 
 199. Dammar. There are several resins known by this 
 name. New Zealand Copal, or Dammar Australis, is dis- 
 tinguished from East India Dammar by its not dissolving in 
 Essential Oils. There is a Dammar brought from the Isle of 
 Amboy na, a product of the Agathis laranthifolia. The 
 Dammar resin met with most commonly under that name is 
 of a tender friable resin ; it greatly resembles Mastic, and is 
 becoming extensively substituted for it. This resin dissolves 
 in Alcohol and in Turpentine, and forms a very clear and 
 transparent varnish, which dries well, but is not free from 
 murkiness. Mastic Varnish is much adulterated with this. 
 
 200. A good spirit-varnish is obtained by dissolving 
 Dammar resin in Alcohol mixed with one-fourth its bulk of 
 Turpentine. 
 
 201. Copal. This name is common to several resins 
 possessing different qualities, according to the tree which pro- 
 duces it. It is brought from the East Indies, Africa, New 
 Zealand, and Brazil. The hardest, and what may be con- 
 sidered the true Copal, is brought from Calcutta. This is a 
 
52 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 very tough and hard resin, which requires to be melted before 
 it will readily mix with its solvent. 
 
 Copal is soluble in boiling linseed oil. Digested in boiling 
 alcohol, it swells, and takes a soft and elastic consistence. It 
 will dissolve in absolute alcohol if previously pulverized and 
 dried at a gentle heat. Camphor added to alcohol, increases 
 its solvent powers. 
 
 Copal, dissolved in linseed oil, forms a very valuable varnish ; 
 and when pale and of the best quality, is preferable to any 
 other as a picture varnish. Being so difficult of solution, it 
 cannot be removed from a picture without destroying it, and 
 serves the more efficaciously to protect it against the wanton 
 attacks of the “ cleaner.” 
 
 202. Copal Varnish is used as a Vehicle in oil painting. 
 
 203. Turpentine has very little action on copal until it is 
 fused, when it becomes readily soluble in it. 
 
 204. It is sometimes desirable to obtaih copal varnish 
 without oil, the following is given as a formula for its prepara- 
 tion : — 4 parts copal, 1 camphor, 12 ether, 4 absolute alcohol, 
 ith camphine. As this mixture is very inflammable, and would 
 be liable to explode if brought near flame, the ingredients 
 should be placed in a warm room, and agitated from time to 
 time until the copal is dissolved. 
 
 205. Amber. Amber is a fossil resin, washed up by the 
 sea in different parts of the world, particularly in the Baltic. 
 It is met with m irregular shaped brittle pieces, of that peculiar 
 yellowish colour to which it gives its name, Amber Yellow. 
 It is translucent, and devoid of taste and smell, partially 
 soluble in ether, but is not acted upon by water or alcohol. 
 It melts with difficulty ; the usual solvent is boiling linseed oil. 
 
ON THE MATERIALS USED IN PAINTING. 
 
 53 
 
 Amber varnish is the hardest and most durable of any ; the 
 only objection that lies against it is its dark colour, which 
 limits its use in pictures containing light hues of blue and red, 
 with white. It was doubtless used as a vehicle by many of 
 the old painters whose works have in consequence become 
 almost indestructible. 
 
 206. Lac. The substance familiarly known as Shell-lac 
 is a resin of animal origin, produced, like kermes and cochineal, 
 by a gall insect coccus lacca ; the females collect in great 
 numbers around the small branches of trees to deposit their 
 eggs, which they cover with a resinous substance ; this is lac, 
 known in commerce as stick-lac. Shell-lac is obtained by 
 melting the stick-lac in boiling water, and pouring it out on 
 flat stones, when it cools and hardens. 
 
 Shell-lac is of a bright orange or reddish brown colour, 
 soluble in alcohol and in a solution of borax, but not in cold 
 turpentine. It is a principal ingredient in sealing-wax, lacquers, 
 and cqrtain manufacturing varnishes. When bleached, it 
 forms white-lac varnish, which from its transparency, hardness, 
 and durability, is recommended for use in the arts. 
 
 207. A red colouring matter is obtained from Lac, known 
 as lac-dye , from which, before cochineal became as well known 
 as it is at present, the finest red pigments were obtained, the 
 red lakes, Indian lake is now the only one in request. 
 
 208. The solution of lac in borax has been proposed as a 
 vehicle, but there does not appear to be any necessity for it, 
 or any advantage to be obtained from its use. 
 
 SOLVENTS. 
 
 209. By distilling crude Turpentine, derived from the 
 
54 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 pinus palustris, of North America, we obtain the Essential 
 oil, Spirits of Turpentine, a clear, colourless liquid, like water, 
 of peculiar odour, and a solvent of most of the resins. The 
 ordinary turpentine of commerce contains a small quantity of 
 resin, as may be seen, by spreading, a little on a piece of 
 writing paper, it leaves an oily-looking stain, after the spirit 
 has evaporated. In making varnishes of brittle resins, the 
 presence of this turpentine-resin is not objectionable, although 
 if present in too large quantities; it produces tackiness. 
 
 Turpentine is insoluble in water; it dissolves in 17 parts 
 of alcohol, the solvent power of the mixture being stronger 
 upon certain resins than turpentine would be alone. 
 
 Turpentine mixes in any quantity with the fixed oils, and 
 oil- varnishes. It serves to dilute them, and enables us to 
 
 apply and spread them' more freely to a surface, while it 
 accelerates their drying. 
 
 210. Spirits of Turpentine- re-distilled, yields Camphine , 
 a spirit of greater purity and solvent power. When spread on 
 paper, it dries and leaves no stain.,. Camphine may be 
 advantageously substituted for Turpentine in all delicate 
 preparations. 
 
 211. Alcohol, or Spirits of Wine , as it is usually termed, 
 is the product of the distillation of fermented liquors. It is 
 a colourless, transparent,, inflammable jiquid,. mixes with water 
 in all proportions, dissolves the essential oils,' and the fixed 
 oils only slightly. 
 
 It dissolves certain resins, forming with them spirit varnishes. 
 The solution of Mastic in alcohol is cloudy, shewing imperfect 
 solubility of the resin. Water added to solutions of resin in 
 alcohol, precipitates the resin. 
 
ON THE MATERIALS USED IN PAINTING. 
 
 55 
 
 Alcohol will not dissolve an oil varnish after it has become 
 hard, nor a turpentine varnish if the resin of which it is 
 composed is insoluble in alcohol. 
 
 212. Linseed Oil. This is the solvent usually employed 
 for the hard resins, Copal and Amber. The great heat required 
 to melt these substances precludes the employment of volatile 
 oils, as before they could act upon the resins, they would be 
 entirely dissipated by the heat. But if an oil-varmsh is too 
 thick, as it generally is, it can be diluted, or made thinner by 
 the addition of an essential oil, as turpentine. 
 
 . The resins appear to possess no siccative property-; it is 
 therefore necessary that the oil used as a solvent should be 
 rendered drying . 
 
 In treating on Dryers and Drying-oils, we have shown the 
 various methods by which pure linseed-oil may be rendered 
 siccative. 
 
 WATER MEDIUMS. 
 
 213. The only medium used in water colour painting 
 necessary to mention, is Gum Water. 
 
 Gum Arabic is soluble in cold water, with which it forms a 
 viscid, adhesive, tasteless solution, to this a little white sugar 
 so added to prevent the gum scaling off when dry, as it is apt 
 to do if too thick. 
 
 214. Gum Water serves to fix the pigments on the paper 
 in which they are applied ; it gives transparency to the shadows, 
 and serves as a varnish to resist abrasion. 
 
 Gum Tragacanth will not dissolve in cold water, but swells 
 up, forming a gelatinous mass, that serves as a water magilp. 
 
 215. Ox-Gall is added to the water colour medium to 
 remove any greasiness paper may acquire from handling, <fcc. 
 
56 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 With delicate blue pigments it should be colourless, or its 
 mellow colour may give them a green tinge. 
 
 VARNISHING. 
 
 216. The object of vanishing a picture is to protect it 
 gainst the noxious agents usually present in the atmosphere, 
 uch as smoke, dust, sulphurous vapours, etc., as well as from 
 
 accident by scratching, chafing, etc, 
 
 217. The application of varnish should be an object of 
 mature consideration, both as to the choice of the varnish, and 
 the time at which it is applied. 
 
 218. The varnish that offers the greatest durability from 
 its toughness and hardness would appear to recommend itself 
 best, these qualities are found combined in an eminent degree 
 in Copal and Amber; those who object to their colour may 
 make use of Mastic. 
 
 219. Before the varnish is applied it should be placed 
 before the fire, so as to drive off any moisture ; the picture 
 should also be thoroughly dry and clean, and the operation of 
 Varnishing performed in a warm, dry room. 
 
 220. A varnish should never be applied to a picture until 
 the paint has become thoroughly hard and solid ; if it be 
 applied before this hardening has taken place, the difference 
 of contraction between the paint and the varnish causes the 
 latter to crack. 
 
 221. An oil-varnish is much less liable to crack than a 
 turpentine varnish; for in the first, there is little or no 
 
ON THE MATERIALS USED IN PAINTING. 
 
 57 
 
 evaporation or contraction, while in the latter, there is, on the 
 contrary, much of both. 
 
 222. The process of Varnishing is so simple an affair that 
 there can be no secrets in it, however much designing empirics 
 may pretend to the contrary. An ignorant quack may mix 
 certain ingredients of the nature of which he knows nothing, 
 but the compound is more likely to be mischievous than 
 salutary to the picture to which it is applied. 
 
 223. When the light of common sense is brought to bear 
 on this subject, all the obscurity of presumptuous ignorance 
 must disappear. Many a valuable picture is irretrievably 
 ruined by a secret varnish. 
 
 224. A good varnish does not become discoloured by age, 
 a nostrum may. If a varnish contains substances that blacken 
 by contact of sulphurous vapours, it fails in the very object for 
 which it is used, namely, — that of protecting the pictures 
 painted with pigments which consist of salts of lead, against 
 noxious vapours. 
 
 225. It has been suggested, that if an artist paints a 
 picture which he intends to endure as long as such perishable 
 things can last, — after his picture has become thoroughly 
 hardened, (which may take twelve months,) let him cover it 
 with some six or more coats of pale copal varnish, treating it 
 just as the coach makers do their carriage bodies, polishing 
 this varnish with pumice, etc., until it resembles a sheet of 
 plate-glass. His picture will then be tolerably safe from 
 every attack of the cleaners, short of actual destruction. 
 
 226. A picture so treated may be pronounced imperishable 
 under ordinary circumstances ; if the canvas decays, it can be 
 re-lined ; the paint is as durable as the varnish, and the copal 
 
58 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 will resist all solvents, and only succumb to rasp, file, razor, 
 or grit-sand. 
 
 227. A good varnish covers a picture like a sheet of plate- 
 glass, through which it can be seen in all the purity of its hues, 
 and by which it can be preserved to future ages in its pristine 
 beauty. 
 
 228. As we have shewn, the quality of a varnish must 
 depend upon the resin of which it is composed ; the varnish is 
 but this resin spread evenly, by the medium of a solvent, over 
 the surface of the picture. If we examine the resin, and find 
 it transparent, slightly coloured, hard, and tough, we may 
 conclude the varnish will possess the same qualities. 
 
 229. A singularly perverse notion seems to prevail, that a 
 varnish, when applied to a picture, must at some time or other 
 be removed. Ho varnish should ever be applied to a picture 
 upon which the shadow of suspicion can rest that it will ever 
 be necessary to remove it. If the varnish is a good one, this 
 necessity can never arise. A varnish may become dirty, but 
 it can be cleaned without being removed, as the dirt is only on 
 the surface, that is supposing it a suitable one, and properly 
 applied. Under ordinary circumstances, only smoke and dust 
 can attach themselves to a picture, these may be easily and 
 safely removed by soap and water, and a soft sponge, unless 
 the varnish is cracked, then only a damp cloth can with safety 
 be applied. 
 
 230. Much of the mischief attendant upon improper 
 varnishing arises from the practice of painting for Exhibitions. 
 Before a picture is scarcely dry, it is varnished; and this 
 varnish is generally applied with the expectation that it will 
 some day require to be removed. If the varnish be the least 
 
ON THE MATERIALS USED IN PAINTING. 
 
 59 
 
 tacky, it gathers up a thick coat of dust, which, as the varnish 
 hardens, dries in, and can only be removed by the removal of 
 the varnish that retains it. 
 
 231. It has been proposed that a temporary varnish of 
 gelatine or isinglass should be applied, which could be sub- 
 sequently removed by a sponge and water without injury to 
 the picture. 
 
 232. Chilling. Many reasons are assigned for the Chil- 
 ling of a varnish. We are inclined to attribute it to the 
 presence of moisture, and if the precautions of warming the 
 varnish and drying the picture are attended to, it will probably 
 not occur. 
 
 PICTURE CLEANING. 
 
 233. In reading the processes usually recommended for 
 Picture Cleaning, we are forcibly reminded of the horrors of 
 the Inquisition and its instruments of torture. Such is the 
 fearful array presented by rasps, files, razors, on the mechanical 
 side, and naptha, ether, alcohol, oil of spike, turpentine, liquor 
 ammonia fortiss, oil of tartar, soda, etc., on the chemical. 
 These are all potent agents of destruction, and it would be 
 better to let the dark veil on a good picture remain for ever 
 than submit to the discipline required by the use of such 
 agents, the injudicious or even incautious use of any one of 
 which would destroy a work of art. 
 
 234. The evidence given before the Committee of the 
 House of Commons clearly shows how little the nature of paint 
 or varnish is really understood. The light of science would 
 appear to have not yet dawned upon the region of art. 
 
60 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 235. Now, as Pictfwre-cleaning is usually Varnish- cleaning, 
 or rather Varnish-removing, it would seem natural that those 
 who take upon themselves the responsible and delicate task of 
 picture cleaning should, at least, have made themselves 
 acquainted with the nature and properties of the materials they 
 operate upon. But, no ! their proceedings are enveloped in 
 the mysteries of quackery, and a host of nostrums are recom- 
 mended and applied without the ‘ slightest knowledge of the 
 effects they are likely to produce, beyond this, that they re- 
 move the varnish somehow and most frequently the picture 
 also. 
 
 236. If the reader has carefully perused the preceding 
 pages, he will have acquired a rational idea of the nature both 
 of paint and varnish ; —that the paint consists mainly of an oil, 
 which, by absorbing oxygen, has become converted into a kind 
 of tough resin ; he will also have learned that this resinous oil 
 is insoluble in water and alcohol, is but slightly soluble in oil, 
 and more readily soluble in turpentine and the alkalies. 
 The Varnish he will have learned consists of resins soluble or 
 insoluble in certain essential and fixed oils. 
 
 237. Now, suppose it is desired to clean an unvarnished 
 picture. The dirt upon it consists most probably of dust and 
 smoke. Sometimes, when pictures are treated as articles of 
 furniture, they are found covered with beeswax. 
 
 If the dirt consists only of dust and smoke, the only solvent 
 necessary is a sponge and soft water. If, however, the smoke 
 and dirt are of long accumulation, a little curd soap will assist 
 in its removal, but the free alkali generally present in soap is 
 apt to attack the oil of which the paint is composed, and con- 
 vert it into soap, so that it must be sparingly applied and 
 
ON THE MATERIALS USED IN PAINTING. 
 
 61 
 
 quickly removed ; and the picture must be afterwards washed 
 with clean water and wiped dry with a piece of wash-leather, 
 else when dry, it will be covered with a white film. 
 
 238. Sometimes the smoke, which generally contains 
 resinous matter, will not yield to soap and water. In that 
 case, we may apply, with a soft sponge, a mixture of spirits of 
 wine and camphine, about seven-eighths of the first to one- 
 eighth of the second. Camphine alone would quickly attack 
 the paint; the spirits of wine has no action upon it, and 
 therefore dilutes the camphine so much that it can be applied 
 without much risk. 
 
 To an unvarnished picture no other application can be 
 recommended or is even necessary. We will now consider 
 the proper mode of treating a varnished picture. 
 
 239. We should commence by trying to remove the dirt 
 by the same means recommended for cleaning an unvarnished 
 picture, which are as applicable to the one as to the other. 
 If the result is not such as desired, and it is decided that the 
 varnish must be removed — an operation that appears to us as 
 revolting as it would be to flay a living Venus — then, after it 
 has been washed, rub one comer of the picture with a piece of 
 folded linen rag dipped in the mixture of Camphine and Spirits 
 of Wine. If it is a turpentine varnish, such as Mastic or 
 Dammar, it will probably soon yield, but if it does not, the 
 quantity of Camphine may be gradually increased. The 
 removal of the varnish will be seen by the condition of the 
 rag, which must be changed as soon as it becomes foul. 
 
 240. If no effect is produced by this application, we may 
 conclude the picture is covered with a hard oil-varnish, such 
 as Copal; in that case, instead of trying to remove it, which 
 
62 
 
 ON THE MATERIALS USED IN PAINTING. 
 
 can scarcely ever be done without injury to the picture, it will 
 be better to polish it with fine tripoli powder and water, or oil, 
 finishing with a piece of soft wash leather. 
 
 241. Knowing the difficult solubility of copal and amber 
 resins, we can appreciate the difficulty attending every attempt 
 at their removal from the surface of a picture by means of 
 solvents. The corrosive agents recommended for that purpose, 
 such as soda, liquor ammonia, oil of tartar, ether, naptha, and 
 alcohol will have very little effect upon the hard resins, while, 
 if they reach the oil-paint, they immediately attack and 
 destroy it. 
 
 242. As for files, razors, and such mechanical agents, it is 
 only necessary to consider the natural unevenness of the sur- 
 face of the most carefully finished picture, to become aware of 
 the utter impossibility of removing the varnish by such rude 
 appliances, without at the same time removing the more 
 prominent parts of the paint as well. 
 
 243. The same remarks apply to rough friction by the 
 finger’s end or palm of the hand; this treatment may be 
 allowable when an old picture has been recently covered with 
 a bad turpentine varnish, which admits of being removed by 
 this means without injury to the picture. 
 
 244. In some pictures the varnish is coloured and employed 
 as a glazing, or the varnish unites so completely with the 
 glazing that the one cannot be removed without the other. 
 
 PRINTED BY RICHARD KEENE, IRON GATE, DER^Y.