The various shades produced by colour ing matters may be classed in one or other of the following group:-
Some colours adhere at once to the. stuff, and are substantial colours: while others require that the material to be dyed should undergo some previous preparation in order to render it per manent. The substance used to fix the colouring matters are called mor dants, which should possess four qualifications:-1, They should possess an equal affinity for the fibre of the material and the colouring matter. 2. They should be incapable of injuring or destroying either by prolonged action. 3. They should form, with the colour, a compound capable of resisting the action of air and water. 4. They should be capable of readily conforming to the various operations of the dyer.
Aluminous mordants are to be used.
The acetate or tartrate of iron must be employed.
407. For scarlets use a tin mordant made by dissolving in strong nitric acid one-eighth of its weight of sal-ammo niac; then adding by degrees one-eighth of its weight in tin, and diluting the solution with one-fourth of its weight of water.
Wash well to remove dressing, and dry; then dip in a strong solution of sulphate of indigo - partly saturated with potash - and hang up. Dry a piece to see if the colour is deep enough, if not, dip again.
Boil the article in alum, and then dip in a strong solution of chemie blue.
Boil an ounce of anatto in three quarts of water, and two ounces of potash, stir well, and put in the calico while boiling, and stir well for five minutes; remove and plunge into cold pump water, hang up the articles without wringing, and when almost dry. fold.
Immerse in the acetate of alumina mordant, and then in the colouring matter of a pink saucer.
Boil the article in an alum mordant, and then in a solution of indigo mixed with any of the yellow dyes, until the proper colour is obtained.