How To Set Dye

Dyed fabrics in clothing and home goods add pizzazz and color to your home and wardrobe, so it's important to keep these items looking fresh and vibrant after washing. To set dyes in your clothing, towels and linens, household items can serve as mordants – or fixatives – to help preserve the colors and protect your other belongings from dye bleed.

StMax89/iStock/GettyImages

Dyes can bleed and fade for any number of reasons. These reasons range from a poor dye quality to user error. Improper dyeing practices or improper type of dye for the fabric in question can both result in bleeding.

One of the most common causes of dye bleed is an excess of dye left in the fabric. Most often, this is a result of the user's failure to rinse the item thoroughly at the end of the dyeing process.

If your craft or sewing projects involve commercial or natural plant-based dyes, you'll need to know how to set the dye. You have basically two options for setting dyes in fabrics.

First, you can use a mordant – or a fixative. A mordant is a substance that gets added into a solution that helps the woven fibers of the cloth "take" the dye more fully. Two common mordants are salt and vinegar.

Alternatively, dyes can be set with heat. This is accomplished by using a hot dryer or iron to create a damp heat that sets the dye on the fabric.

It's important to check the dye manufacturer's recommendations carefully before proceeding with a dye project. These requirements can vary according to the type of fiber as well. Some dyes may set best with salt if you're dying cotton fabrics, for example, while silk or wool fabrics should be set with vinegar.

It's always a good idea to try a test-dye on a small sample piece of fabric first before dyeing the larger piece.

To test for color-fastness on new items of clothing, such as dark denim or brightly colored clothes, rub a piece of plain white paper against the fabric. If the paper shows no discoloration, you're probably safe to wash the item as usual. Just use cold water and a detergent that's made for cold-water laundry cycles.

If some color does transfer to the paper, you'll want to pretreat the item before washing to help set the dye. You'll also want to take special care with the item going forward, both to protect that item and other items that may come into contact with it in the wash.

The problem here is that you don't know what dye was used to color the fabric in the first place. Different dyes can have different effects on various fabrics. Without this information, it's important to take a few key actions to help set the dye in colorful items of clothing, whether that's a pair of dark denim jeans, brightly colored towels or a colorful shirt.

First, try a pretreat solution. In a household bucket, pour enough water to submerge the item and add 1 cup of white vinegar. Turn the item inside out and soak the item for at least an hour.

After the pretreatment, wash the item in your machine. Don't add any other items to the washing machine to avoid dye contamination on other pieces of clothing. Use half the recommended amount of detergent and add a 1/2 cup of white vinegar. Also add a tablespoon of salt. The chloride in the salt helps seal in the color to keep it from fading.

Wash in cold water, both during the initial vinegar wash as well as going forward. Using cold water in your washing machine helps you preserve vibrant colors and keep them from fading. It also helps cut down on your energy bills.

You may also want to add a color-catcher sheet in the washing machine when you launder colorful items. These sheets help trap – or "catch" – bleeding dyes in the water. Although they won't prevent colors from fading, they can at least protect your other clothes from castoff dye.

Some experts suggest adding 1/2 cup of baking soda to each wash cycle when laundering colorful clothing. Baking soda does seem to help preserve the vibrancy of dyed clothing.

In addition, a small amount of baking soda in the wash can also help keep your whites bright and prevent them from becoming dingy over time. Baking soda also softens the water. As a result, you'll need less detergent per load.

If you're already dealing with a dye bleeding onto another piece of clothing, there are a few ways you can deal with this issue.

If the item is a solid white cotton or cotton blend that's free of elastic, soak the item in a diluted bleach solution. Use 3 tablespoons of bleach per gallon of cold water. Fully submerge the clothing in the bleach solution and let it soak for up to five minutes. Rinse the item thoroughly in fresh, cold water, then air dry the piece. If the dye is removed, you can wash as you normally would. If some dye remains, repeat the process.

Alternatively, you can use a commercial product designed to remove colorful dyes. If your item is not bleach-safe or if it contains elastic, this is a preferable method for addressing a dye bleed. Follow the manufacturer's directions when using commercial color removers.

Finally, you can follow the "if you can't beat them, join them" method by over-dyeing the piece. Choose a shade that is similar to the dye bleed but slightly darker. This should help cover up the bleed. If the item of clothing in question has stripes or some print over a lighter background, this will probably be the only solution possible. As with commercial color removers, follow the manufacturer's directions to the letter, as dyes made for home use can yield some unpredictable results.