Test It Yourself: Coloring Gray Hair

One of the most important swatch tests you can perform measures the effect of natural or neutral colors when covering gray. While you're at it, consider whether permanent or demipermanent products are the best choice.

Permanent color, used with 20-volume developer, provides 100-percent gray coverage and opaque results. The results are most opaque with tube colors, which have a lower ammonia content, and less opaque with liquid colors, which usually have higher ammonia levels.

Many clients-especially those who have with higher percentages of gray/white-prefer a more opaque color.

Gray blending, using deposit-only color, is also popular. Deposit-only or demipermanent color is more transparent and has the added advantage of being low-maintenance: as it fades, the regrowth is less obvious. Many colorists foil in a smattering of complementary highlights, particularly through the heaviest gray/unpigmented areas, and then apply a demipermanent color between the foils. This is particularly effective around the front hairline and through the top, where gray tends to dominate.

With any approach, the farther you move away from the natural level and tone, the more obvious the regrowth. This is why many colorists stay within two levels of the pigmented hair and adjust up or down, based on the ratio of pigmented to unpigmented hair. In the case of white hair, adding highlights or moving into lighter blondes may be best. But this is where lifestyle, maintenance and budget come into play.

The biggest mistakes made in gray coverage are formulating color that is too dark or light, using the wrong developer and underprocessing. Most manufacturers recommend using 20-volume developer and processing for 45 minutes to achieve optimal gray coverage-otherwise the color tends to "slide off."

Guidelines for formulating permanent color for gray coverage are:

Percentage of gray	Formula adjustment
Up to 25%	Use one level lighter than the color you want to achieve.
25-50%	Use one part desired color and one part of a color that's one level lighter.
50%	Use the desired color.
50-75%	Use one part desired color and one part the next darker color.
75-100%	Use color that is one level darker than the desired level.

Modify the formula and application at retouch time, and use a demi-permanent color on the midshaft and ends when refreshing.

Also, modify the formula's tonality based on the amount of gray. Neutral/natural series colors may be used by themselves to infuse the hair with a balance of the three primary colors-particularly on high percentages of gray-and prevent the color from going "off-tone."  Always follow the manufacturer's recommendations for high percentages of gray.