Under this style, will be included the so-called "China blues" - designs in blue on a white ground; the kinds where reserves or resists are printed upon the cloth, which is then dyed in the vat, thus producing white, yellow, and orange designs on a blue ground; and lastly, the style named "lapis "or "lazulite."
(1) Put into a colour pan, 8 lb. 2 oz. indigo, finely ground in water, 4 lb. 6 oz. indigo in 26 pints liquid. Heat; and add 6 lb. 9 oz. ground gum. Dissolve; and add 11 lb. saturated hydrosulphite, 15 1/2 oz. milk of lime, containing 7 oz. lime per If pint. Heat to 158° F. (70° C.) for 20 minutes; cool down to 104° F. (40° C.); and add 3 lb. 4 oz. saturated hydrosulphite, and 15 1/2 oz. milk of lime. The yield is 30 lb. 12. os. of colour.
(2) Mix 22 lb. bleu-gommt (explained below), 13 lb. 2 oz. gum water, 15 lb. 5 oz. saturated hydrosulphite, and 32 3/4 oz. milk of lime.
These colours must always be used warm, never under 80° F. (30° C), nor over 95° F. (35° C). Nor must they be used too soon after they are prepared. Those colours give the best results, which show a greenish hue till the next morning.
When the colours are printed, the pieces are spread out overnight in an airy place, or, if necessary, they may immediately after printing be passed through a weak lukewarm chrome beck. In either case they must be very well rinsed, washed and soaped, for 30 to 45 minutes at 122° to 140° F. (50° to 60° C). If the whites are not good, they are taken through weak chloride of lime. If this blue is printed along with other colours, the pieces may undergo the treatment necessary for such colours, without any attention being paid to the blues. Passing through soda, sulphuric sours, chrome baths (warm or cold), alkaline, chrome and lime baths, silicate of soda, phosphates of lime or soda, cow-dung, etc, has no effect on these blues.
The bleugomme is prepared as follows: - 4 lb. 6 oz. good Bengal indigo are ground up in the ordinary manner, employing water enough to make the paste up to 35 pints. This placed in a boiler, made up with water to 105 to 140 pints, along with 11 1/2 lb. caustic soda-lye at 62° Tw. and 30 3/4 lb. hydro-sulphite of soda. It is heated to about 156° F. (70° C.) for 15 to 20 minutes. Then 131 fl. oz. hydrochloric acid are poured in through a long-necked funnel, reaching to the bottom of the vessel. This operation should be performed under a chimney, as much sulphurous gas is given off. If the liquid has a faintly acid reaction, the decomposition is complete, and the whole is poured into a cask capable of holding 280 pints, which is filled up with water. The next morning, the liquid standing over the sediment is run off through holes in the sides of the cask, till the bottom is only covered to the depth of 9 to 10 in. The vat is then filled anew with water, to which 4 per cent, by measure of saturated hydrosulphite is again added. The next day the water is again drawn off, and the sediment is thrown upon a filter, and washed. When completely drained, 7 lb. of a dense paste are obtained for every 2 lb. indigo originally employed.
To preserve this paste, it is suspended in gum water. The yield, as above, is mixed with 44 lb. thick gum water, containing in each 1 3/4 pint 3 lb. 1 oz. gum. This mixture is the bleu gomme. Gum Senegal should be used, as starch, calcined starch and tragacanth have given bad results.
5 1/2 pints water, 6 lb. 9 oz. lime-juice at 53 1/2° Tw., 11 lb. pipe-clay. Mix also separately: 5 1/2 pints water, 4 lb. 6 oz. lime-juice at 53 1/2° Tw., 3 lb. 13 oz. corrosive sublimate, 11 lb. calcined starch, 12 3/4 oz. lard, 6 1/2 oz. turpentine, 3 1/4 lb. muriate of zinc at 98° Tw. Mix and boil.
7 pints red liquor, 62 oz. verdigris, 9 lb. 13 oz. pipe-clay, 4 7/8 oz. lard, 4 7/8 oz. turpentine. Dissolve also separately: 12 3/4 oz. arsenious acid, 5 1/2 pints acetate of alumina. Mix also apart: 3 1/2 pints acetate of alumina, 3 1/4 lb. gum Senegal, 17 1/4 oz. muriate of zinc at 98° Tw., 8f fl. oz. extract of logwood at 6 3/4° Tw. Mix these three parts with the aid of heat, grinding them very well, and straining before use.
The cylinders for printing should be engraved very deeply. The pieces are next aged for 48 hours, at a temperature of 95° F. (35° C.) with the wet-bulb thermometer at 89° F. (32° C). Dry for 12 hours thoroughly at 86° F. (30° C). If left damp, the pieces will not resist the vat. Dye blue for 3 to 5 minutes in the cold vat. Drain, wash for 1/4 hour in a current of water. Dung in folds for 1/2 hour in a beck at 140° F. (60° C), with 4 pails of dung, and 15 1/4 lb. chalk, for 6 pieces of about 50 yd. Wash; and dung a second time in the same matter, but without chalk; and wash. Dye for 2 hours at 140° to 158° F. (60° to 70° C), in the following beck: 8 lb. garancine (for which will now be substituted a proportionate quantity of alizarine), 6 lb. 9 oz. sapan-wood, 11 lb. sumach, 17 1/2 lb. bark, 7 pints glue in jelly (containing 17 1/2 oz. dry glue). Wash till no more colour runs off; chlore at 3/4 Tw. Wash; dry; block in yellow, If needed; and age for 24 hours at 86 F. (30° C.) the wet-bulb thermometer standing at 80° F. (27° C).
1 1/4 lb. dry indigo, ground and prepared, 1 1/2 lb. tin crystals, 1 gal. caustic soda at 30° Tw.; put into the colour pan, and raised to a boil in 1/2 hour, when 1 gal. boiling water is added. The mixture is then allowed to become quite cold, and 2 gal. cold water are added, in which 1/2 lb. sugar has been previously dissolved. To this solution are added 2 1/2 pints muriatic acid at 32° Tw., or 1 pint ordinary oil of vitriol, previously diluted with 1 pint water, and allowed to'stand till cold, or 3 qt. acetic acid at 80° Tw. The indigo blue may also be precipitated by a mixture of double muriate of tin at 120° Tw., with any of the acids above mentioned, taking 1/4 pint of the tin solution to half the quantities of acid given above. But of all these precipitants, acetic acid alone is preferable. The indigotine precipitate is filtered through a deep conical filter, leaving exposed to the air as small a surface as possible. The pulp obtained from the above quantities, when filtered, should measure about 1 gal. To make a blue colour for printing, take 4 gal. of the above precipitated indigo, and 14 lb. gum Senegal in powder, stirring till dissolved. The colour, when strained, is ready for printing.