To cover unpigmented hair in a salt-and-pepper client, the color formulation should be:

The correct approach for covering unpigmented (gray or white) hair, particularly in a salt-and-pepper client, is to use a color formulation that is two levels lighter than the natural hair color. This strategy is effective because it allows for better blending of the natural hair (which has some pigmentation) with the unpigmented strands.

Using a lighter shade helps achieve a more natural look, creating dimension and reducing the stark contrast between the pigmented and unpigmented hairs. If the color applied was the same as the natural level, it may not adequately cover the gray, leading to a lack of uniformity. Similarly, choosing a shade that is only one level lighter may not provide enough contrast for effective coverage. Opting for two levels darker would not only fail to cover the gray, but it could also make the overall color appear too dark and potentially unnatural against the lighter strands. Thus, selecting a formulation two levels lighter is the most suitable option for achieving a balanced and blended appearance.