Red ochre
Composition and Properties of Red Ochre
The main color giving component of natural red ochre (ocher) is composed of hematite (∝-Fe2O3). The term red ochre (ocher) or red earth describes various kinds of iron oxide pigments such as Venetian red, mars red, English red, Indian red. The nomenclature is by no means unequivocal and various authors have used the names differently. See reference (2) for a more thorough analysis of the usage of different terms.Iron oxides are stable at high temperatures but not resistant against acids. The pigment is absolutely stable as is documented by the cave paintings still in excellent condition after many thousands of years.
Names
Red earth, red ocherPR 102, CI 77491From Old French ocre (c. 1300) and directly from Medieval Latin ocra, from Latin ochra, from Greek khra, from khros “pale yellow,” a word of unknown origin. From Online Etymology Dictionary
Preparation
The natural mineral is washed in order to separate it from sand and other impurities. The resulting sludge is dried and the pigment is ground and sieved.Deposit of natural red and yellow ochres in Roussillon, Vaucluse, France
History of Use
Red ochre has been in use since prehistoric times until the present day. The following graph gives the frequency of its use from the 14th until the 19th century in the paintings of the Schack Collection in the Bavarian State Art Collections in Munich (1).Examples of use
Quote
The primitive man may have taken a pleasure in beating women as well as in drawing animals; all we can say is that the drawings record the one but not the other. It may be true that when the cave-man’s finished jumping on his mother, or his wife as the case may be, he loves to hear the little brook a-gurgling, and also to watch the deer as they come down to drink at the brook. These things are not impossible, but they are irrelevant. The common sense of the child could confine itself to learning from the facts what the facts have to teach; and the pictures in the cave are very nearly all the facts there are. So far as that evidence goes, the child would be justified in assuming that a man had represented animals with rock and red ochre for the same reason as he himself was in the habit of trying to represent animals with charcoal and red chalk. The man had drawn a stag just as the child had drawn a horse; because it was fun.
Source: The Everlasting Man
