GREENISH RAW UMBER
This greenish-brown okhra is obtained from natural earths, coloured by the oxides of iron and manganese. It is the content of manganese that causes so many different hues in the atlas of umbers. For Greek Orthodox painters, such greenish pigments were used in frescos as a first layer, in order to prepare the “sarcoma”, the background for the flesh of holy figures.
Chemical formula Fe2O3 • nH2O + MnO + Al2O3 • 2SiO2 • 2H2Ο
Stability to light 7 (scale 1/8)
Specific weight 3,50
For fresco, tempera, oil, encaustic, watercolour
