In the following test, the results are based on just one permanent hair color brand we tested, but the principles remain the same. For hair that's 25 to 40 percent gray, our brand recommended three parts of the desired color be mixed with one part of the natural series. For 40 to 70 percent gray, the desired color is mixed 1:1 with the natural series; for 70 to 100 percent gray, one part of the desired color is mixed with three parts of the natural series. The brand also required a 1:11/2 color to developer ratio and recommended a 45-minute processing time. Consider how yours results may vary, based on your manufacturer's instructions.
1. Use a mannequin head with pigmented, neutral Level-4 hair that's approximately 50-percent gray and divide it in quadrants. Apply a formula of 1/2-oz 5N with 3/4-oz 20-volume developer to the first quadrant. This shade, with its three primary colors and an emphasis towards blue, should provide a true neutral, balanced result and optimal gray coverage. Once fully processed, the color should be opaque and solid.
2. Apply a formula of 1/4-oz 5A and 1/4-oz 5N mixed with 3/4-oz 20-volume developer to the next quadrant. (Depending on a client's natural level and tone, an ash color like this, with its blue-green base, neutralizes unwanted orange or gold pigment.) On hair that's 40-percent gray or higher, mixing in equal proportions with the neutral series should modulate the coolness of the end result.
3. Apply a formula of 1/4-oz 5G and 1/4-oz 5N with 3/4-oz 20-volume developer to the third quadrant. The gold base of the 5G will add golden tonality and warmth to the formula. On hair that's 40-percent gray or higher, the equal proportions of desired color to the neutral series modulates the amount of warmth in the end result. See if this is evident when you compare quadrant 2 to quadrant 3.
4. Apply a formula of 1/4-oz 5R and 1/4-oz 5N with 3/4-oz 20-volume developer to the last quadrant. The true red base of 5R shades, when combined with a neutral series, should provide beautiful red tones and superb coverage when used on hair that's 40-percent gray or higher.
You'll also want to repeat the test using demipermanent products. One part 5N mixed with a very low-volume developer should provide balanced, neutral results without excessive warmth or coolness. The difference will be that the gray blends with the pigmented hair, exhibits variations in lightness and darkness, and appears more sheer or translucent.
Swatching out color formulas helps you become intimate with specific brands. It elevates your confidence, and if you make notes on your findings and put them in a binder, you'll have a valuable reference tool for yourself and your colorists-in-training.