What Is a Wash or a Flash in Hair Color?

by Lisa DiVirgilio ; Updated September 28, 2017

A flash or wash-out color can be the perfect, non-permanent transformation into a new you.

Image by Flickr.com, courtesy of Zoe

Coloring your hair can make a dramatic difference to your appearance. But if you're not sure which color would be best, a flash or wash may be the best route to take. Flashes and wash-out hair colors are non-permanent hair dyes that change the color of your hair. These color transformations last for about four to six weeks, depending on how often you wash your hair.

Strand Test

Many people dive right into coloring their hair without taking the necessary time to prepare, especially if it's not permanent. If you are getting a flash or wash done by professionals, they will be able to tell you what colors match your skin tone. If you are doing the coloring from a box, you can do a strand test.

A strand test helps in two ways. It is a basic allergy test to make sure that your skin and hair will not have a reaction to the chemicals required for the color change. It shows you the color that your hair will turn after it has set.

Remember, what you see on the box is not always what you will see on you. Colors vary depending on the color of your natural hair and your hair texture. To perform a strand test, take a piece of hair near the bottom of your head, close to your neck. Brush the dye into the strand, and wait the amount of time written in the instructions before washing it out. The results should be a good indicator as to how your hair will accept the color.

Preparing Your Hair

If your hair is not prepared for color, your results could end in disaster. The color can come out uneven, with lighter color either on the end or the roots. Even worse, you can do all-over, irreversible damage. This is more likely to happen when hair is not healthy.

To get the best color possible you need to trim off split ends and make sure your hair has a healthy retention of moisture. You can boost the retention by giving yourself a deep oil or conditioning treatment. These are available at your local drugstore and are relatively inexpensive.


Be realistic about the amount of time you will spend doing your hair, especially if you plan on doing it yourself. Always choose a more conservative color. Dying your hair a new color every week, even if it is a wash or flash, is not a great idea. It will cause damage to the point that it may become brittle, lose its elasticity and possibly fall out. When you want a new color, but have no idea what will work, it's best to visit a salon. At the very least, they can give you the pre-trim you'll need beforehand, and you'll leave with some suggestions for color from a professional.


Do not shampoo your hair the day you plan to color it. You should definitely shampoo your hair the day before to remove all excess styling products and any dirt buildup, but leave it at that. Shampooing your hair the same day as you color your hair will remove from your scalp the natural oils that help to protect your skin from hair dye chemicals. While flash dyes do not have as much harmful chemicals in them as permanent hair dyes do, they have enough to burn your scalp, so let your natural oil protect you from possible damage.

Extra Hands

For best results if you're doing it on your own, have a friend help you. There are spots in the back of your head that you may not noticed have not been completely saturated in dye, which can leave your hair color uneven, especially around the crown of the head. At the very least, use a hand-held mirror with your bathroom vanity mirror to check out the back of your head near the scalp and neckline. Also remember, if you have longer hair, it is safer to get two boxes of hair color. One box of hair color typically works for shoulder length or shorter hair.

Photo Credits

  • Image by Flickr.com, courtesy of Zoe