From the manufacturer's website:

The Quickshade Blue Tone Wash is loaded with heavy blue pigment in the popular Warpaints ink resin base. Use on top of white for an instant blue toned and shaded miniature or on top of blue colours for extra depth and shading. Try experimenting with Warpaints: Barbarian Flesh and Necrotic Flesh for that cold from the grave look - very striking!Shading and colour toning in one wash.