Since dye is transparent, it won't work to try to dye on top of a dark background. The dye will not show up. You can still get the same effect, however. There are three different materials that are used to 'dye' onto a dark background:
1. chlorine bleach (hypochlorite)
2. color remover (sodium hydrosulfite)
3. opaque fabric paintNone of these are true dyeing. The first two are discharge agents, meaning that they remove or destroy the dye in the fabric. The last uses pigment to cover up the dark dye.
Ordinary household bleach, such as Clorox, is hypochlorite, a highly toxic chemical which destroys most organic substances it touches. This includes dyes, but also animal fibers such as wool, and synthetic fibers such as polyester, nylon, and spandex. Cellulose, the main constituent of cotton, is somewhat resistant, but it can be damaged, as well, unless you use a bleach neutralizer immediately after using bleach on it. Unneutralized bleach will gradually eat away at your cotton, causing it to develop holes after a while. Bleach can harm you, as well: avoid skin contact and exposure to fumes. Wear reusable plastic gloves, not the thin latex ones, which may not provide sufficient protection. Work only with excellent ventilation, using an appropriate respirator (not a dust mask) to protect you against the fumes as needed.
Go ahead and tie your garment just as you would for tie-dyeing; you may dampen it first with plain water, or tie it dry. Dilute your bleach before putting your tied garment into it; how much water you should use for a given amount of bleach depends on the dye you are trying to remove, so you may need to experiment. Start with ten times as much water as bleach. A very convenient way to apply small precise designs of hypochlorite bleach is with a Clorox Gel Bleach Pen.
Before you place your item to be bleached into the bleach, you must prepare to neutralize the bleach, so that you can do so as soon as the color has lightened sufficiently. Fill your washing machine with water, before you begin, and get your neutralizing bath ready, as well. The most economical bleach stop agent is Anti-chlor, or sodium bisulfite, which PRO Chemical & Dye sells for less than two dollars for a half-pound package that might last you for years. Alternatively, at greater expense, you can use hydrogen peroxide (the 3% strength sold as an antiseptic), or a strong oxygen 'bleach' such as Oxy-Boost. The peroxides in these products will harmlessly neutralize the hypochlorite. Do NOT use vinegar to neutralize the bleach: acids are dangerous when combined with hypochlorite, causing the creation of even more caustic chemicals!
Using rubber gloves and tongs, place your tied garment into a suitable container (such as a plastic dishpan) with the bleach, or pour or spray the bleach mixture. Jane Dunnewold's book Complex Cloth illustrates this process. As soon as your garment has lightened sufficiently, rinse it with water, saturate it with Anti-chlor or another suitable neutralizer, then wash it immediately.
Not all dyes will lighten with bleach, though others will lighten at the slightest touch. It is impossible to predict whether a given fabric will discharge in bleach until you test it. You may buy hundreds of black shirts from one vendor that bleach wonderfully, only to find that the next batch of shirts from the same supplier do not react at all to bleach. The only way to be sure (unless your supplier guarantees it) is to do the dyeing yourself, using an easily discharged fiber reactive dye such as Vinyl Sulfone Dye.
Color Remover, or sodium hydrosulfite, is a desirable alternative to chlorine bleach, as it is less damaging. Instead of destroying the dye molecules, it breaks the bond between dye and fiber. Unlike chlorine bleach, it can be used on silk, wool, and nylon, though you must be careful to avoid damaging the fiber. Again unlike bleach, Color Remover does not have to be chemically neutralized; thorough washing should be sufficient to remove it.
Two brands of sodium hydrosulfite are Rit Color Remover and Carbona Color Run Remover. Use according to package directions. If you want to use it on a large quantity of material, buy several packages and use it in the washing machine.
Some dyes respond better to sodium hydrosulfite than to bleach; others do the reverse. Not all dyes are dischargeable with any agent.
Like dyes, most fabric paints are transparent. The only ones that will work on a dark background are those specifically labeled as 'opaque', 'metallic', or 'pearlescent'. Fabric paint is basically a pigment mixed with a glue, not at all like a dye, but highly suitable for some purposes. Be careful to follow any instructions given for making the paint permanent. Some fabric paints require heat-setting.
After discharge-dyeing your fabric so that it has light markings on it, you can apply fiber reactive dye for brilliant colors against a perfect black background. Be sure to neutralize bleach properly first, and wash it thoroughly, before attempting to dye.
Page created January 30, 2003
last updated: January 19, 2006
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