This is a subject that is dear to my heart. I teach color theory and there is little information to be found for the concrete use of neutrals. Let me say this....A neutral is any color that is not on the color wheel. The color wheel only contains pure color and those pure colors that have black, gray or white added to them. Neutrals are bias with colors from around the color wheel. The key to using neutrals is the same for all colors. That is to make sure your selection has varied value and the largest proportion of color choice shares the warmth or coolness of the neutral.