DISCHARGE STYLE.-By a " discharge" (enlevage), is understood a mixture which, if printed upon cloth previously dyed some uniform colour, e. g. Turkey-red, vat-blue, aniline-black, &c., destroys such ground colour, leaving a design which may be white, black, yellow, green, &c. The term " discharge style" is more especially applied to patterns of this nature obtained upon a Turkey-red. The following colours will serve as examples of these discharges:— White (for cylinder work).—Tartario acid, 6 lb.; water, 1 gal. ; starch, lb.
White (for block work).—Tartario acid, 10 lb. ; China-clay, 7} lb. ; perchloride of tin, 1 lb. ; gum water, 1 pint ; water, 1 gal.
Black.—Logwood liquor at 4° Tw., 1 gal.; yellow prussiate, 2 lb.; thick gum tragaeanth water, I qt. ; flour, 2 lb. Boil, and add blank liquor at 30° Tw., 2 qt. When quite cold, add nitrate of iron at 80° Tw., 1 gill.
Blue.—Tartaric acid, 5 lb. ; water, I gal. ; tin pulp, 1 gal.; double muriate of tin at 120° Tw., 2 gal. ; gum tmgacanth water, 2 gal.
Yellow (block).—Lime-juice at 50° Tw., 1 gal. ; tartaric acid, 4 lb. ; nitrate of lead, 4 lb. When dissolved, add China-clay, 6 lb.; gum senegal, 3 lb.
Yellow (oylinder).—Thicken the former with lb. starch, instead of gum and China-clay.
After any of these discharges is printed on, the pieces, when dry, are passed through the decolouring vat," which is made up of 1000 gal. water and 1000 lb. chloride of lime, well raked up, and freed from lumps. A double set of wooden rollers at top and bottom is placed in the vat, and the liquid is kept constantly stirred up, so as to be perfectly uniform. The pieces are now allowed to run through the liquor at the rate of 28 yds. in 3 minutes. On leaving the vat, they arc run between squeezing-rollers into water, and are then rinsed for 10 minutes in solution of bichro mate of potash at 4° Tw. Wash in pure water, then in water soured with muriatic acid, and lastly in pure water ; after this, dry. Except where the discharge was printed on, the Turkey-red is unaffeeted ; but thorn, it is removed, and the ground is either left white, or a mineral colour takes its place.
STEAK COLOURS.—This style has latterly undergone a very great development. It includes the proceasea by which the aniline colours in the majority of cases are fixed upon cotton goods, and, in addition, the topical application of the colours formerly obtained from madder, but now produced artificially. Printing upon woollen, worsted, and silk tissues, as well as upon mixed fabrics, such as delaines, coburga, &e., is included in this style.
The aim of steaming is to get a moist heat, both the temperature, and the degree of moisture, being carefully regulated, according to the class of the goods, the nature of the colours, &c. In somecases, the pieces after printing are exposed to the air, at common temperatures, for 12-24 hours before steaming ; whilst in others, they are steamed immediately. Sometimes, the goods are steamed for a time, taken out to air, and steamed again ; whilst on other occasions, the steaming is conducted for the necessary time without interruption. The temperature, the pressure, and the degree of moisture, vary greatly, some printers using very dry, and others very moist, steam.
The apparatus in which the steaming is performed is called the " steam-cheat," an iron chamber, generally about 9 ft. high, 6 ft. wide, and 12 ft. long. At one end, are well-fitting fold ing doors, capable of being closed tightly, and held in place by bars and screws. The cheat has a double bottom, the upper layer of which is on a level with the floor of the room, and is perforated with a great number of holes. Underneath this false-bottom, runs a steam-pipe, extending round three aides of the chest, and also perforated with holes, through which the steam escapee, and is further distributed by means of the holes in the false-bottom. A tramway is fixed upon the false bottom, parallel with the aides of the steam-chest, and extending out into the room. Upon these rails, runs a carriage consisting of wooden rods, fixed in an oblong frame, as wide as the chest will allow, and as high as where the elope of the roof begins.