PIGMENT STYLE.—The colours employed in this style are not soluble dyes, but insoluble colours or pigments, which are fixed upon the fibre by various mediums. This style has of late been much improved, and offers the advantages of solidity and permanence, combined with a lightness and brilliance equalling, in many cases, those of colours formed in the fibre.
The pigments chiefly employed in this style are ultramarine of various shades, from greenish blue to a full blue, violet-blue, and even a reddish-violet ; vermilion; several ochres ; zinc-white ; certain chrome colours, such as chrome-yellow, chrome-green, Guignet's green, Wilner's green, lamp-black ; sienna ; umber, &c.
The vehicles or mediums employed for attaching these pigments to the fabric are albumen, casein, or, as it is often called, lacterine. Blood-albumen may be used for all save the lightest and brightest colours. The pigments are ground up in albumen, thickened often with gum tragacanth, printed and steamed. The albumen is thus coagulated, and the colour is permanently attached to the fibre.
Pigment printing is chiefly confined to such parts of designs as consist of small dots, stars, and flowers ; more rarely to broad stripes, large foliage, &c. It affords the means of producing many pleasing effects which would not otherwise be practicable.
Pigment colours, and other colours fixed by means of albumen, may be discharged by printing in the juice of the papaw-tree (Carica papaya), thickened with gum.
Aniline Black—Aniline black seems to form a distinct style, but is capable of being combined with a great variety of colours, produced according to the styles already described.
Aniline Blacks for Yarn Printing.—Gum tragacanth water, 11 pint ; water, 21 pints ; sublimed aniline muriate, 91 oz.; chlorate of potash, 21 oz. Immediately before use, work in 21 oz. sulphide of copper. The colour thus made is printed ; the pieces are dried, and aged for 48 hours at 30°
(86° F.) in a moist atmosphere. As soon as the colour appears of a blackish-green, the yarns are washed, taken through weak bichromate of potash, then through a solution of soda, washed, and dried.
Aniline Black for Machine Work.—Chlorate of potash, 159 parts ; sal ammoniac, the same weight ; moist sulphide of copper, ]50 parts; white starch, 360 parts ; calcined starch, 180 parts ; water, 2300 parts. Boil, stir till cold, and add 317 parts sublimed aniline salt, previously dissolved in 9000 parts cold water.
Prussiate Aniline Black.—Chlorate of aniline, 34 parts ; prussiate of aniline, 12 parts ; water, 31 parts; gum tragacantb water (containing 4tl oz. per 11 pint), 12 parte. This mixture may also be thickened with starch paste, both for block and machine work.
The chlorate of aniline is prepared by dissolving 5 parts tartaric acid in 10 parts boiling water, and, separately, 4 parts chlorate of potash in 12 parts boiling water. These two hot liquids are mixed together, 20 parts cold water and 3 parts aniline being added. After this addition, thy liquid takes a faint yellowish tinge, and stands at 91° Tw.
To obtain a prussiate of aniline, treat 7 parts yellow prussiate with 3 parts sulphuric acid, pre viously diluted with 14 parts water. After some days, the yellow colour disappears, and a deposit of sulphate of potash is formed. To 100 parts of the solution thus obtained, are added 128 parts of water and 20 of aniline.
White Discharge upon Aniline Blacks.—Thicken an acid solution of the permanganate of potash with finely-ground siliceous earth and China-clay, and block on. Take through oxalic acid, when dry. No organie matter must be used for thickening the permanganate.