Name: Tegan
Message: I have a 100% cotton dress, which was green, and am trying to lighten it as much as possible to re-colour it purple. I've bleached it and it's gone a brownish-yellow. Is there any way of lightening it further? I've read on the website for people to try Dylon Colour Run Remover. But is it normal to not be able to lighten any further?

It's perfectly normal to find that your commercially-dyed garment has been colored with dyes that simply cannot be discharged. No matter what you do to some dyes, they will stubbornly retain their color. There is no way to know, until you try it, whether the garment that you want to bleach will respond to your efforts. It all depends on the specific dye. Most garments are dyed with multiple dyes, some of which will stay after others are removed; sometimes this can produce surprising colors.

I have written an article about the different chemicals that can be used to remove dye from dyed fiber: see "What chemicals can be used to remove dye?".

Household chlorine bleach is based on hypochlorite, a toxic oxidizing chemical that breaks apart dye molecules. Sometimes a dye will bleach to nearly white, but other dyes will turn to funny colors (often ghostly browns), and some will stay the same color even after the hypochlorite has eaten the fabric into rags. Hypochlorite is very damaging to fabrics made of fibers other than cotton, linen, or hemp, but even these sturdy fibers can be damaged if exposed to too much bleach, or for too long. To help reduce additional damage due to hypochlorite bleach, neutralize the garment with Anti-Chlor or hydrogen peroxide: see "How can I neutralize the damaging effects of chlorine bleach?".

Other discharge chemicals are kinder to the fabric, and also produce different results from hypochlorite bleach. In some cases, color remover will work when bleach will not, and in some other cases, bleach will work when color remover will not. It's pretty much unpredictable, since you rarely know what dye was used to color your dress. (One case in which sulfur-based discharge chemicals will NOT work is blue denim, which is dyed with indigo; to remove color from blue jeans, you pretty much have to use bleach.) If you wash your dress thoroughly after trying one dye-removing chemical, you can go ahead and try the other. If bleach did not work, you can wash the dress well and then try Dylon Color Run Remover. You might get better results, but you also might not. Once you've used one sulfur-based discharge chemical, such as Dylon Color Run Remover, don't bother trying another, such as Jacquard Color Remover (Thiox), because they give similar results to each other, though different from those produced by hypochlorite bleach.

Dylon Color Run Remover, also called Dylon Run Away, is just like Rit Color Remover: both contain sodium dithionite (also known as sodium hydrosulfite), plus sodium carbonate (also known as washing soda). They work best in very hot water, on the stovetop, in a non-aluminum pot, but they are much easier to use in the washing machine, and the washing machine method often works. If you are going to be using it in a washing machine, be sure to check the label to see if you need to use several boxes at once. There is no need to neutralize these sulfur-based dye removal chemicals after use, unlike chlorine bleach.

If your dress remains yellow even after your best dye removal efforts, then you will not be able to dye it a bright purple, since yellow is the opposite color to purple. Only if the yellow is pale will any purple be a possibility. Otherwise, dyeing it purple will just produce brown. In that case, you might try dyeing the dress black, instead. If you do, avoid all-purpose dyes, such as Dylon Multipurpose or Rit. You'll get better results with a fiber reactive dye such as Dylon Hand Dye, Dylon Machine Dye, Dylon Permanent, or Dylon Cold Water dye. Expert dyers prefer the wide color-mixing possibilities of Procion MX dyes.