Dyes used in Oriental rugs
In the middle of XIX century chemical rug dyes are spread over all of the oriental countries. The law issued by Persian government that prohibited its import, including the order to stop work on all rugs manufactures that used them, had no effect on the situation. Cruel punishment that was in cutting off right hand of any dyer who was guilty of breaking that law was soon forgotten. After the World War I chemical dyers were used all over the world. Aniline dyes, found by English chemist Perkin (1856), surely, had a fatal effect on the color perception of the oriental rugs, but since that times lots of high quality synthetical dyes were discovered, and nowadays they are used everywhere.
However, other qualities of the plants' pigments cannot be substituted. Although cloth panted with those pigments loose the intensity of color, get old, but thus their colors become milder. Besides that, they are able to give colours so deep and mild that even at high intensity never look irritating. The recepies of dying were considered to be a secret of workshops or clans, being transmitted further on by heritage, as well as all of secrets of a craft. The same is with everything we said about the material. While dying a lot depended on the climate and the type of soil on which the plants grew. Quality of the wool also influenced the tone of a color of a dye - using the same production process the varying quality often gives varying tones of colors. The material ment for dying is first washed in the hot water and degreased, sometimes using even soap, after which it is put in a bath for twelve hours. In the dying bath itself it lies for a very long period of time, after which it is dried in the sun. On manufacture plants every time is dyed a big enough portion of raw material is dyed while the nomads. who can dye only one small portion at a time, do not achieve every time the same color tone of a dye, which is the reason why one can meet various tones of the same color on a single carpet, as, for example, on the background picture, which is quite big solid surface.
Nowadays for dying wool meant for carpet manufacturing they mostly use chrome dyes. Buying a handmade rug, no matter if the dyes are natural or synthetic, you can be sure that it's value will increase as time goes. Even the rugs that have been made at the end of XIX century using anyline dyes are valued very high because of their age.
There is a popular opinion that a rug that has been dyed using natural dyes are unconditionally better than a rug created using chrome dyes. This is a wrong idea. Chrome dyes quite often turn to last longer and be tougher than the natural dyes.