BaMnO4BaSO4. An artificial mineral pigment. Barium sulphate – permanganate. Introduced as an artists’ colour in the 1930s. The pigment was widely used to colour cement and within the ceramics industry. The toxicity of the manufacturing process for manganese blue seems to have played a part in its downfall.
Sadly, production (in Europe) of this valuable pigment ceased in the late 1980s. Best used independently as a glaze.
Very bright, cold blue with a greenish cast. Transparent. Stable in oil. Fast drying 1-2 days in thin applications. Milled in walnut oil, to help preserve the pure blue colour – because Manganese Blue has a catalytic effect on vegetable oils, it helps dry the (normally slow drying) walnut oil paint film.