We may observe that a strong mordant, like No. 2., does not keep so well as one of mean density, such as No 1. Too much mordant relatively to the demands of the works should therefore not be made at a time.
There are eight different styles of calico-printing, each requiring different methods of manipulation, and peculiar processes.
1. The madder style, to which the best chintzes belong, in which the mordants are applied to the white cloth with many precautions, and the colours are afterwards brought up in the dye-bath. These constitute permanent prints.
2. The padding or plaquage style, in which the whole surface of the calico is imbued with a mordant, upon which afterwards different coloured figures may be raised, by the topical application of other mordants joined to the action of the dye-bath.
3. The reserve style, where the white cloth is impressed with figures in resist paste, and is afterwards subjected first to a cold dye, as the indigo vat, and then to a hot dye-bath, with the effect of producing white or coloured spots upon a blue ground.
4. The discharge or rongeant style, in which thickened acidulous matter either pure or mixed with mordants, is imprinted in certain points upon the cloth, which is afterwards padded with a dark-coloured mordant, and then dyed, with the effect of showing bright figures on a darkish ground.
5. China blues; a style resembling blue stone-ware, which requires very peculiar treatment.
6. The decolouring or enlevage style; by the topical application of chlorine or chromic acid to dyed goods. This is sometimes called a discharge.
7. Steam colours; a style in which a mixture of dye extracts and mordants are topically applied to calico, while the chemical reaction which fixes the colours to the fibre is produced by steam.
8. Spirit colours; produced by a mixture of dye extracts, and solution of tin, vulgarly called spirit by dyers. These colours are brilliant but fugitive.