PADDING STYLE.—This is a further modification of the madder style. The pieces are padded over with red and black liquor, dried in the so-called padding-flue ; the pattern is printed on in lime-juice and bisulphate of potash, thickened generally with starch, thus removing the mordant from certain parts. After ageiug, dunging, and dyeing, the design appears in white, on a claret, scarlet, or purple ground.
It is, of course, easy to convert the white design into a yellow, or to block in steam or pigment colours.
Immo EFFECTS.—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." Effects of the first kind, direct indigo blues, are now very simply produced by means of the " hydrosulphite " process of Schutzenberger and De Lalonde.
Direct Indigo Blues.—(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, 15i oz. milk of lime, containing 7 oz. lime per 11 pint. Heat to 70° (158° F.) for 20 minutes ; cool down to 40° (104° F.); and add 3 lb. 4 oz. saturated hydrosulphite, and 15i oz. milk of lime. The yield is 30 lb. 12 oz. of colour.
(2) Or,—Mix 22 lb. bleu-gommg (explained below), 13 lb. 2 oz. gum water, 15 lb. 5 oz. saturated hydrosulphite, and 321 oz. milk of lime.
These'colours must always be used warm, never under 30° (80° F.), nor over 35° (95° F.). 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 30-45 minutes at 50°-60° (122°-140° F.). 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, &c., has no effect on these blues.
The blets-gomme 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 is placed in a boiler, made up with water to 105-140 pints, along with 11 lb. caustic soda-lye at 62° Tw. and 30f lb. hydrosulphite of soda. It is heated to about 70° (158° F.) for 15-20 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 decoinposition 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 9-10 in. Tho vat is then filled anew with water, to whioh 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. of 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£ pint 3 lb. 1 oz. gum. This mixture is the Gnm senegal should be used, as starch, calcined starch, and tragacanth have given bad results.