Caput mortuum belongs to an older language of pigments and chemical preparation. The name has been applied inconsistently to reddish-brown iron-oxide materials, including heated preparations. It is better understood as a historical family of names than as one unchanging substance.
Violet-brown oxides can give a colour subdued red-purple depth without the brightness of a vivid violet. Their earthy character makes them useful for understanding the quieter side of red and purple in historic-looking palettes.
Violet ochre is not a precise chemical formula, and caput mortuum is not a universal synonym for every violet earth. Names alone cannot establish the material used in a particular paint.
These articles explain pigment and mineral families, not the sourcing or complete formulation of any Cameron Colours paint. Historical names can cover different materials. Follow the product guidance and safety data for the paint you use; do not handle or heat raw pigment powders at home.
