From the manufacturer's website:

The Quickshade Purple Tone Wash is loaded with deep Purple and heavier dark pigment in the popular Warpaints ink resin base. Use on top of white for an instant purple toned and shaded miniature or on top of purple, red or blue for extra depth and shading. Check the Barbarian flesh example in this entry.As all the Quickshade Inks, it looks stunning on a metal primer for that Slaaneshi look.Shading and colour toning in one wash.