The Kato Polyclay Mixing Chart is a comprehensive guide to mixing intermediate colours, tints and shades using:
Standard Kato Poly Clay Colours
Adding black to a standard colour creates a shade or darkened colour.
Adding white to a colour creates a tint, or a lightened colour.
Mixing two standard colours creates an intermediate colour.
The Kato Polyclay Mixing Chart uses segment ratios to measure portions (of black: colour: white) required to achieve 154 different colours, tints and shades.