With silks, advantage may be derived from various metallic solutions which possess the property of staining animal substances; among which are nitrate of silver, nitrate of mercury, and muriate of iron. The solutions of these salts may be thickened with gum, and printed-on.
An orange upon an indigo vat ground.—After the blue ground has been dyed, orange figures may be produced by printing-on the following discharge paste:—
1 gallon of water, made into a paste with 1 pound of starch: when cold, add to it from 16 to 24 ounces of nitric acid, of spec. grav. 1·288. After fixing the colour by steam, the orange is brightened with a soap boil.
An orange upon a Prussian-blue ground.—The dye is first given by Prussian blue in the ordinary way, and then the following discharge is printed-on:—
A caustic lye being prepared, of 1·086 specific gravity, dissolve in a gallon of it 2 pounds of annotto, and thicken with 3 pounds and a quarter of gum. Two days after the impression of this paste, pass the goods through steam, and wash them in running water. With these two designs, the logwood and gall black, formerly described, may be associated, to produce a rich effect.
To the preceding practical instructions for printing calicoes, silks, woollens, and mixed fabrics, made of the two latter, a few annotations may be added.
When an uniform colour is to be applied to both sides of the cloth, the padding process is employed; but, when only one side is to be thus coloured, diagonal lines are cut very closely to each other upon the cylinder, which transfer so much colour from the trough to the cloth passed under it as to make the surface appear uniformly stained. This process is called mattage by the French. Mordants or topical dyes, to be applied in this way, should not be much thickened.
The doubler is the piece of felt or blanket stuff placed between the cloth to be printed, and the block printing table, or the cylinders. It should be kept very clean; because, were it soiled with acetate of iron, it would spoil all the light shades made with acetate of alumina.
Filters for the colour shop of a print house are best made of wool, formed into a substantial conical cap by felting. A filter ought to be set apart for each different dye stuff.
When the goods after dyeing are washed, by being held by the selvage, dipped, and shaken in a stream of water, the process is called giving a list by the French (donner une lisière). The piece is transferred alternately from one hand to another.