Caput Mortuum is particularly fine powdered red iron-III-oxide, which has a special color. It is used as a pigment, where the origin can be natural and synthetic.

The somewhat strange name probably comes from the allchemist laboratory of yesteryear. The meaning of the name is: "skull". Roasting pyrite / marcasite to produce sulfuric acid required a very high temperature. And the remaining dry residue was iron III oxide, but in a very fine bluish violet form. Today's production of this bluish pigment is different, but the name has remained the same.

The choice of color supports the artist's intention. In his figurative paintings he likes to focus on the individual parts of the body depicted, who are expressions of the inner state of mind and condition: face, hands and other parts of the body. The viewer's attention automatically moves to what is visible, what in the artist perspective is essential for the painted character. This brings us very close to the person depicted, almost too close to what we see and feel. Great fine watercolor painting with a high expression that definitely leaves the beholder impressed!

https://www.mineralienatlas.de/lexikon/index.php/Caput-mortuum?lang=de

Max Doerner. Painting material and its use in the picture. 19th ed., 2001.

http://de.wikipedia.org/wiki/Caput_mortuum

http://kremer-pigmente.de/caput-mortuum.htm