DYEING (OF. ((yea, to dye. AS. di'a gin from dray, color; connected with AS. (Vow, dew). The art by which various substances, especially textile fibres, are impregnated with coloring matters with sulicient tenacity to resist the action of water or ordinary wear.
Ilisroar. The art of dyeing was known to the ancients. and it is mentioned in the Bible that Jacob gave his favorite son 'Joseph a coat of many colors, and Moses tells how the .Skins of the ram and the badger used for the Tabernacle were dyed red. The purple of the Tyrians was known at an early date: the King adopted it as one of his principal ornaments, and it has since continued a badge of royalty. Accord ing to Pliny. this purple color was derived from certain shellfish found along the coast of Film nieia, but the method of its preparation was lost. Pliny is also the authority for the state ment that methods of dyeing black. yellow, and green were brought into Greece from India ou the return of Alexander the Great. Toward the close of the Middle Ages the art of dyeing was greatly developed in northern Italy. especially in Florence. where the dyestuff :India (q.v.) was discovered about 1300. The early voyagers to America brought back with them new and valu able dyestuffs, such as cochineal, lob good, and quereitron. Subsequently dyeing developed according to the discoveries of new dyestuffs, and the application of improved processes, until about the middle of the nineteenth century.
Since then, the natural dyestuffs have been gradually giving way to artificial colors derived mostly from coal-tar (see COAL-TAR COLORS). The most important natural and artificial color ing matters may be found described in articles under their special names. A list of the best known artificial dyestuffs may be found under Coat.-Tan Comas. Mineral and vegetable dyes were formerly considered more lasting than the artificial hut this view has. in most cases, positively no foundation in fact. The accompany ing table shows which artificial substances have either partly or completely displaced natural ones in the dyeing of animal and vegetable fibres.
Dyestuffs have been roughly divided into two classes, viz., substances which are capable of permanently dyeing fabrics by themselves. with out the aid of other substances, and substances which cannot dye fabrics without the aid of the so-called 'mordants.' It nmst. however, be re membered that the same substance may act as a dye of the first class with animal fibres, and as a dye of the second class with vegetable fibres: and vice versa. For example. picric acid acts as a 'substantive' color with silk or wool, while cot ton fabrics cannot permanently he dyed with it.