On hair with very light yellow underlying pigment, obtain cool ash gray to very silvery gray tones, depending upon processing time. The intensity of gray increases when you increase processing time. SHAMPOO + MASK Combining the Shampoo and the Mask gives you a more intense end result with better neutralization on yellow or gold hair and stronger enhancement of gray tones on pale yellow or platinum hair. Excellent to use when creating pastel tones or refreshing tonality. It can be mixed with other shades in the color reflection series to cool the shade down while maintaining the tone, or to create metallic or chromatic color variations. Ref: 10412