Ash tones are based in blue or violet colour, and the hair colour products are commonly labelled as "V" or "B." Ash tones deposit the violet or blue colour to neutralise orange and red tones when applied over orange or red-toned hair.
Neutral Tones and Gray Hair
Gray hair already has an ash tone to it. To avoid exacerbating the grey, a red-toned brown can be used, though a neutral tone hair colour is recommended. Neutral and neutral beige tones, labelled as "N" and "NB," provide a neutral base when covering grey hair.
Ash tones in hair colour effectively counter red tones, though neutral tones are best to use when colouring grey hair.