i also found this...
Fit to be dyed?
By Ann Geracimos
THE WASHINGTON TIMES
The miracle works of modern man do not at the moment include a surefire dye to change the color of many so-called miracle fabrics.
****That means such grand-occasion garments as prom, bridesmaid and wedding dresses, often made of polyester, are not easily recycled into everyday-occasion clothes simply by dipping them into a vat of dye.
(none)
****So-called miracle or artificial fabrics do not respond well to the treatment, industry professionals say. Commercial dry cleaners in the Washington area that once offered the service no longer promote that end of the business. The only companies nationally that regularly dye clothing are in California, according to the International Fabricare Institute of Silver Spring.
****"It is just so difficult to do, and results weren't that great," says Brian Grozbean of Lustre Cleaners of Capitol Hill Inc. "Most clothing is too expensive, and people won't risk it, especially since many of today's fabrics are blends [with polyester, acetate or rayon] that don't take the dye very well."
****The reason has to do with the molecular components involved, says Laura Medhurst, associate professor of chemistry at Marymount University in Arlington.
****"Fibers in polyester and acetate are chemically inert, meaning they don't have any ions [electrically charged atoms] that allow them to react to an outside substance. They are inflexible," Ms. Medhurst says.
****"Fibers have different chemical structures, and so do dyes," she says. "Most vat dyes such as Rit have large molecules, so when you boil a fabric with the dye, the fibers are loosened, and the dye gets trapped inside. Acid dyes are different from a vat dye because they are fiber-reactive and are absorbed in another way."
****Dyes are a mix of pigments that must be combined with a mordant — a fixative such as salt — to set the coloring.
Typically, a consumer using dye at home uses heat and then cools a garment by washing it in cold water.
****"You try never to use hot water ever again if you can avoid it," says Ms. Medhurst, because the color may run.
****She doesn't encourage the use of dyes that come directly from plants such as indigo, marigold or madder because the garments will have a tendency to fade.
****"It's not a property of the dye, but of the fabric being dyed.
If you notice, you will see plant-based fabrics such as linen or cotton seldom come in bright colors. They will fade because the fibers themselves are what a chemist would refer to as not very polar or reactive," she says.
****Animal-based fabrics such as wool and silks behave differently, Ms. Medhurst says, because they are made out of protein that has an ionic charge. "The result is you can have beautiful, brilliant colors."
****To fully control the outcome, the original dye in the garment has to be removed first with a special light bleach sold in craft or fabric stores.
****Starting with a white fabric makes the process much easier for consumers attempting the dyeing process at home, says Leah Kanic, buyer for apparel fabrics, books and patterns at G Street Fabrics in Rockville.
****"Otherwise, if you really want a precise effect, you will be disappointed," she says. "Overdyeing makes it hard to predict the outcome." Those who think they can cover up stains by dyeing a garment will usually get a mottled look instead.
****Another key bit of advice is to know the kind of fiber being dyed, whether a natural or synthetic. The easiest way to test fabric fiber is to take a tiny sample off the seam allowance and burn it, Mrs. Kanic says.
****"You will find that a synthetic will melt, but a natural fiber like wool and silk will sizzle or reek like burning hair. Cotton, linen and rayon will burn like paper," she says.
****Fabrics are divided into two categories: natural and synthetic. Natural fabrics are either plant- or animal-based. Cellulose fiber, from plants, includes rayon, cotton, linen and novelty fibers such as hemp and ramie.
****"Rayon is not environmentally friendly because of the chemicals used to make it," Mrs. Kanic says.
****Animal fibers such as wool and silk are harder to deal with, she says. "You could use a pink dye earmarked for plant-based fabrics on white silk and have it become a brown or mauve color. I once took a piece of wool hoping to make it gunmetal gray, and instead it came out midnight blue."
****A good resource for the consumer is a Web-based California company called Dharma Trading (www.dharmatrading.com), which gives free online instruction in dyeing of every kind by category, including a high-end consumer dye called Procion. G Street Fabrics sells both Rit and Procion, which Mrs. Kanic says is almost as good as the commercial dyes used by clothing manufacturers. Garments dyed with Procion don't fade nearly as fast as those colored with cheaper dyes, she says.
****Dyeing man-made artificial fabrics such as polyester, nylon and acetate is possible only with chemicals that Mrs. Kanic says the ordinary consumer would not want to deal with because of their toxicity:
"Polyester basically is plastic and would be like dyeing the computer. Acetate is not very stable, but it's possible to try dyeing it, although the garment could be destroyed because acetate doesn't like to get wet. And I tell customers to typically dry-clean rayon unless I know what they are doing with it."
****She also warns consumers to wear a breathing mask and gloves when handling dye in powder form because different kinds of metal are involved.
****Spectrum Custom Fabric Dyeing in Walnut Creek, Calif., (
www.spectrumfirm.com), which does mail-order, handles any dyeing project except polyester but hopes to begin a service for that fabric in the future.
****"It's a risky and involved process," says spokesman Alex Marinov. His mother, Dafinka Dimova, who is the business's owner, is a chemical engineer trained in the technology of chemical fibers. He suggests querying with a description by e-mail to dafinka @spectrumfirm. com before sending garments. They can match any of the standard colors in
www.Pantone. com, he says.
****Greg Heymann, owner of Deluxe Dye Works and Area Rug Cleaners in San Jose, Calif., says prices at his firm begin at $25 a garment for, typically, a pair of Levis. Mail-order takes two weeks. Gloves dyed to match cost a minimum $17. Dyeing garments for reuse is a dying custom, he notes. "It's more of a throwaway society now."
****
