74. HAMBURGH LAKE
Is a lake of great power and depth of colour, purplish or inclining to crimson, which dries with extreme difficulty, but differs in no other essential respect from preceding cochineal lakes—an observation which applies to Roman Lake, Venetian Lake, and many others; none of which, however beautiful or reputed, is entitled to the character of stability either in hue, shade, or tint.
75. DRAGON'S BLOOD
Is a resin brought from the East Indies. It is of a warm semi-transparent, rather dull red colour, which is deepened by impure air, and darkened by light. There are two or three sorts, but that in drops is the best. White lead soon destroys it, and in oil it dries with extreme difficulty. It is sometimes used to colour varnishes and lackers, being soluble in oils and alcohol. Although it has been recommended as a pigment, dragon's blood does not merit the attention of the artist.
76. INDIAN LAKE,
Likewise called Lac Lake. This is obtained from the lac or lacca of India, a resinous secretion which seems to depend upon the puncture of a small insect—coccus ficus—made for the sake of depositing its ova on the branches of several plants, found in Siam, Assam, and Bengal. The twigs soon become encrusted with a mammelated substance of a red colour more or less deep, nearly transparent, hard, and having a brilliant conchoidal fracture. The roughly-prepared coating is imported in two forms, called lac-lake and lac-dye, which contain about 50 per cent of colouring matter, combined with more or less resin, and with earthy matters, consisting chiefly of carbonate and sulphate of lime and silica.
Indian lake is rich, transparent, and deep,—less brilliant and more durable than the colours of cochineal, but inferior in both respects to those of madder. Used thickly or in strong glazing, as a shadow colour, it is of great body and much permanence; but in thin glazing it changes and flies, as it also does in tint with white lead. In the properties of drying, &c., it resembles other lakes. The pigment may be dispensed with in favour of madder lake and madder brown, whose combinations serve for every purpose to which it can be applied, and are stable.
Lac appears to be the lake which has stood best in old pictures, and was probably employed by the Venetians, who had the trade of India when painting flourished at Venice.
MADDER LAKES.
Rubric Lakes, or Field's Lakes, are derived from the root of "rubia tinctorum," a plant largely grown in France and Holland, whence the bulk of that used in England is obtained. The French madders are in a state of very fine powder, containing one half their weight of gum, sugar, salts, and other soluble substances, which water speedily dissolves. Madder roots in the unground state are imported from the Levant, and called Turkey roots. Good qualities of Turkey madder yield near sixty per cent of extractive matters, a term that includes everything removable by water and dilute alkalis: the woody fibre is therefore about forty per cent. This is presuming the root to be genuine, for madder is often adulterated with brickdust, red ochre, red sand, clay, mahogany sawdust, logwood, sandal and japan-wood, and bran.