Vandyke brown

Composition and Properties of Vandyke Brown

Vandyke brown is an organic natural pigment consisting of materials found in brown coal, peat or generally in soil. Considerable confusion can be found in the older mentions of this pigment. It had been considered an inorganic iron pigment mainly in France and its name had also been used for various earth pigments such as umber and ochres.Its color can vary according to the thickness of the painted layer and ranges from pure black with a reddish-violet tint to grayish brown. The main chemical component of this pigment are humic acids and as such, they react with alkalis. The pigment is not stable to light and fades over time. This is mainly due to the oxidation of the organic material on air which is facilitated by light. The pigment is compatible with all other pigments and is often used in mixture with several other pigments.