Cobalt Drier - Highly concentrated, use in very small amounts. Excess could lead to cracking. Provides well-balanced drying. No effect on hue or gloss.
Courtrai Drier - Greater drying power than White Drier. Reduces the difference that exists between the normal drying nature of most colors and the slow drying tendency of certain other colors. May be used directly, avoid excess.
White Drier - Colorless drier containing calcium salts, which activate the pigment's natural driers. No effect on hue or the quality of the brush stroke. Non-yellowing.