Per the instruction sheet for Color by Robert Craig, add 1 Tablespoon of warm tap water to the applicator bottle. Important: DO NOT put the powder in the bottle before the water. DO NOT use hot water. (Baby-bottle warm water is best. Check the water temperature on the inside of your wrist.)

Open the bottle of color and measure 1/4 Teaspoon of Color by Robert Craig powder and add to bottle with warm water to make a small amount of mixture. Be sure to recap the bottle for use after the test. Vigorously shake mixture for 2-3 full minutes to produce a mousse-like consistency. For other brands of color, mix a small amount according to instructions. For liquid colors usually mixing a capful of color and a capful of developer is enough to do this.

You can either snip a 1/4 inch thick piece of hair from your head from somewhere underneath so it won't show and tape one end of the hair so it stays together or better yet, separate a bit of hair about half the thickness of a pencil on the surface of your hair and place either plastic wrap or tin foil under it to keep it separate from the rest of the hair. A clip can be used to keep the foil or plastic in place. If you have any highlights in your hair be sure to include a little of them in this strand.

Apply the color to the strand of hair and time for 5 minutes at a time. This is a perfect amount of time over previously colored or bleached hair or for when you want or need to refresh the mid portion and ends. If you have not colored your hair before or are just checking the result on the new growth to cover grey then you can leave the color on for 45 minutes or according to manufacturers directions.

Tip: If you have a salon colorist do your color then have them do a strand test as well. This way you get to see the work on your hair before committing to a total change. The colorist can do strand tests for highlights, single process and even double process or any combination. This way you are both on the same page.

With a dampened rag, clean off the hair. You will want to clean it off from the scalp to the ends and use the blow dryer to dry the strand. It is best to view the strand of hair over a white piece of tissue or paper to see the true color and look at it in different lighting.

This is what to look for:

Color too dark? you know you need to leave less time.
Color is just what I wanted? go ahead and apply the color to the ends of the hair for the time indicated by your test
Color went orange or violet or too red? then you know the hair is very porous and you need less time or need to add some Clear to your formula to make a lighter shade.
Color didn't change much? then you know you can leave the color on for another 5 or 10 minutes.