CAR′MINE

Syn. Carmine red , Vegetable scarlet ; Carmi′num , L. A beautiful red pigment prepared from the cochineal insect. Prep. The preparation of carmine is little understood, but succe in its manufacture depends le on any mystery connected with the proce than on the employment of the purest water and the best materials, and the exercise of moderate care, dexterity, and patience. The following forms will produce carmine of the richest hues down to ordinary and common, according to the skill po e ed by the manipulator. 1. ( Madame Cenette’s proce . ) Cochineal (in powder), 2 lbs., is boiled in pure river water, 15 galls., for 2 hours, when refined saltpetre (bruised), 3 oz., is added to the decoction, and the whole boiled for 3 or 4 minutes longer; salt of sorrel, 4 oz., is next added, and the boiling again renewed for 10 or 12 minutes; the heat is now removed, and the liquid allowed to settle for about 4 hours, after which time it is decanted with a syphon into shallow plate-like ve els, and set aside for three weeks. At the end of this time the film of mould which has formed on the surface is dexterously and carefully removed, without breaking it or disturbing the liquid beneath it. The remaining fluid is next very carefully removed with a syphon, and the adhering moisture, as far as po ible, drained off, or sucked up with a pipette. The residuum, which is the carmine, is dried in the shade, and po e es extraordinary lustre and beauty. 2. (Alxon or Langlois’ proce .) Powdered cochineal, 1 lb., is boiled in river water, 4 galls., for 10 minutes, when carbonate of soda, 3 ⁄ 4 oz., di olved in water, 1 pint, is added, and the whole again boiled for 1 ⁄ 2 hour longer; when the decoction is cold, alum (in fine powder), 3 ⁄ 4 oz., is thrown in, and the liquid agitated rapidly until it is entirely di olved; after 20 minutes’ repose it is decanted into another ve el, and clarified by heating it with the whites of 2 eggs; the perfectly clear liquid is then allowed to repose for 40 minutes or longer, when it is decanted, and the carmine which it has deposited is collected, drained on a filter, and dried on shallow plates covered with silver paper. The product by either of the above proce es varies from 9 1 ⁄ 2 to 10% on the weight of the cochineal employed in them. 3. ( China or Spirit proce . ) Cochineal, 1 lb., is boiled for 15 minutes, in water, 3 galls., powdered alum, 1 dr., is next added, and the whole again boiled for 5 or 6 minutes; when the liquid has become cold, the clear portion is decanted, and again heated, the solution of tin (spirits of tin) cautiously dropped in until all the carmine is precipitated; it is collected, drained, and dried, as before. Prod. 1 1 ⁄ 2 oz. 3. ( French proce . ) From cochineal (in powder), 1 lb., boiled for 15 minutes, in water, 3 galls.; cream of tartar (in powder), 1 oz., is then added, the boiling further continued for 10 minutes, and powdered alum 1 1 ⁄ 2 oz., thrown in; after another 2 minutes’ boil the heat is withdrawn, and in 5 or 6 minutes more the clear portion is decanted into porcelain ve els, which are set aside until the carmine falls down. 4. ( German proce . ) Powdered cochineal, 1 lb., water, 4 galls.; boil 15 minutes, add powdered alum, 1 oz.; boil 3 minutes longer, remove the heat, allow the liquor to settle for 5 minutes, pour off the clear portion into porcelain or earthenware ve els, and set them aside for 3 or 4 days. The carmine is found deposited on the bottom of the ve el, and must be now carefully drained and dried, as before. The decanted liquor yields more carmine by standing in fresh ve els. Product. About 1 1 ⁄ 2 oz.; besides 1 ⁄ 2 oz., or more, of an inferior quality obtained as a second deposit. 5. ( English proce . ) From cochineal, 1 lb., and carbonate of potash, 1 ⁄ 2 oz., boiled in water, 7 galls., for 15 minutes; the ve el is then removed from the fire, and powdered alum, 1 oz., added; the liquor is then well agitated and allowed to settle for about 15 minutes longer; the clear liquid is next decanted into a clean copper, and isingla , 1 ⁄ 2 oz., di olved in water, 1 pint (and strained), added; as soon as a coagulum forms upon the surface, the heat is removed, and the liquid is strongly agitated with a bone or silver spatula, after which it is allowed to repose for 20 or 30 minutes. The deposited carmine must be drained and dried, as before. Obs. The best black cochineal is generally used for the preparation of carmine. For ordinary qualities spirits of tin (bichloride) is added to the decoction as a precipitant, and the liquid being put into suitable ve els (wash-hand basins answer very well), a deposit of carmine slowly takes place. Neither exposure to solar light nor artificial heat is advisable during the drying, but the latter must neverthele be effected with all po ible expedition. Hence the finer shades of carmine can only be succe fully made during certain states of weather; as in very hot weather the liquid rapidly sours or ferments, and the deposit is more or le di olved; whilst in dull, damp weather it is difficult to dry the precipitate sufficiently, which is then apt to become mouldy, and to lose colour. The researches of Pelletier and Caventou tend to show that the solution of tin used as a precipitant should be at the maximum of oxidation or chlorination, to produce the richest shades of carmine. That first deposited is, in all cases, the most beautiful, and the quality gradually deteriorates as the proce proceeds. 6 or 7 dr. only of carmine of the very finest quality can hence be obtained from 1 lb. of cochineal. Prop., . Pure carmine is a very light, lustrous, scarlet powder, entirely soluble in ammonia, a test by which its purity is readily determined. Mr Warren De la Rue says the pure colouring principle of cochineal is carminic acid. By digesting ammonia on carmine until all the colour is taken up, filtering and adding acetic acid and alcohol, till the whole is precipitated; and lastly, carefully washing the precipitate with spirit of wine, at proof, and drying in the shade, carmine of the richest and most lustrous hue may be obtained even from samples of inferior quality. Uses, . As a pigment in velvet and miniature painting, and for tinting artificial flowers, and as rouge for the complexion. The powdered cochineal (carmine grounds), from which the coloured liquor (liquid rouge, carmine liquor) has been decanted, is used by the paper stainers, and both are used in the preparation of car min a ted lake.