LAKES (Fr. laque. from Pers. ha-, lac, from Skt. 16kxmi, Inc-insect, from lakxa. hundred thousand. so called in reference to the numbers of the insects). Insoluble colored compounds of metallic bases with dyestuffs. They may be obtained either by direct eombination of metallic hydroxide, with coloring matters, or by the addi tion of metallic salts to alkaline solutions of the matters. the alkali of the latter then de composing the salts, with formation of the cor responding metallic hydroxides. In dyeing. these hydroxide, are termed 'mordants."Fhe more common basic mordants include the hydroxides of aluminum. tin, and iron. According to Pliny end other early writers, pigments were fre quently collected from the waste dye liquors of Brazil-wood. kermess etc., which they designated as larrw. The color of lakes often depends both ppm the nature of the hydroxide and that of the dyestuff employed. Carmine lake. which is pre pared by precipitating the coloring matter of cochineal, as by adding sodium carbonate to a cochineal decoction containing alum or stannous chloride, is of a beautiful scarlet color. Accord ing to the place where it has been manufac tured, carmine lake is named Chinese, Florentine, Hamburg, Roman, or Venetian. Madder lake, hich is also of a bright red color, is made by dissolving the extract of madder or garancine in ammonia and then precipitating with alum or stannous chloride. It is also known as liquid
madder lake. maroon lake, or rubric lake. Brazil-wood yields a coloring matter which, when treated similarly to the foregoing. produces a purplish red lake. Logwood yields a lake which is of a violet color. Addition of gypsum or kao lin to the Brazil-wood lake yields the so-called 'rose-pink lake.' Persian berries and quereitron yield yellow lakes, that from quereitron being sometimes called Dutch pink. Madder lake has been largely superseded by the alizarine red lake, which may be prepared by dissolving commercial alizarine in an aqueous solution of caustic soda, which is then treated with a solution of alum containing a small quantity of calcium chloride. Variations in color may be produced by adding the purpurines. The various lakes yielded by the coal-tar colors find extensive applieation in the arts, for paper-staining, in printing, in lithog raphy, in general decorative painting, in calico printing and silk-dyeing, and in preparing colored varnishes for ornamental metal surfaces, wood, leather, glass, etc. For detailed information, con sult the authorities referred to under DYEING COAL-TAB COLORS (qq.v.).