image from NYTimes.
A mythical red dye, called Dragon's Blood , would cause the wearer's death. This appears as an integral part of one of Shakespeare's tragedies. A wronged woman gives the offending interloper a beautiful red robe dyed with Dragon's Blood, of course. I don't remember the actual outcome, just the intended one.
E.J.W. Barber, in her scholarly book, Prehistoric Textiles, says that Pliny classic writers used the Greek term, sandaraca, for a beautiful red mineral that was also used as a dye. The same mineral was used in paintings through the Renaissance. The mineral is realgar, a soft red arsenic compound. In Colors: The Story of Dyes and Pigments says that it was one the red pigments used by prehistorical Egyptians in paintings, cosmetics and medicines. Realgar was only mined by prisoners, another dimension to the dangers of mining. Arsenic can be absorbed through the skin and tiny amounts can give one a very beautiful complexion, as the Victorians knew. But arsenic accumulates in the body and continuous wearing of garments impregnated with realgar, though strikingly red, would make the wearer extremely sick with in a month.
Today, Okotex (sp?), a European organization that sets standards for dyed textiles has different standards for outerwear (little contact with the skin), intimate wear (worn on the skin), sportswear (sweat leaching possible) and babywear (saliva leaching possible). The fewest dyes are acceptable for babywear, natch. Many dyes contain heavy metals that can accumulate in the body if they make it in.
Processing of the dye can be as important as the dye itself in the effect on the body. Residual soda ash is quite irritating to the skin. The wash down procedure for fiber reactive dyes is the critical step in determining their safety. The wash down process is long and arduous, takes as long or longer than the dyeing. Standard industrial procedure is wash at a boil with ample agitation followed by extensive rinsing. Procion MX is the hardest to wash down.
Someone mentioned indigo rubbing off on the skin. Indigo is the oldest known dye and can be done so that it does not crock, it takes skill and care. The Tuareg, also known as the blue people, and others like excess indigo on the surface of the cloth because of the sheen that it gives but that is a cultural preference. We have a 5000+ year history of exposing people to indigo and haven't yet noticed any ill effects. Yet there was an incident in the early 1990's with Smith& Hawkens, or 7th Generation trying to be environmantally aware and having some sweaters hand-knit with some yarn dyed with natural indigo. The hand knitters broke out from the yarn, the skin on their hands and arms was a mess. Some more than others, but it was all natural, what could be the problem? Well indigo requires a high pH, achieved with wood ash, soda ash or lye, to dye. The yarn had not been properly neutralized and the residual alkalinity was causing all the trouble.
This entry was precipitated by some conversations on the dyerslist, where I also posted it.
