Ochre or Ocher (pronounced /'əʊ.kə(r)/, from the Greek ὠχρός, yellow) is a color, usually described as golden-yellow or light yellow brown.
As a painting pigment, it exists in at least four forms:
- Yellow ochre, Fe2O3 • H2O, a hydrated iron oxide
- Red ochre, Fe2O3, the anhydrate of yellow ochre, which turns red when heated, as this drives off the water ligands.
- Purple ochre, identical to red ochre chemically but of a different hue caused by different light diffraction properties associated with a greater average particle size
- Brown ochre (Goethite), also partly hydrated iron oxide (rust)
For further information, see the articles on the individual ochres.
They are found throughout the world in many shades. Many sources consider the best brown ochre to come from Cyprus, and the best yellow and red ochre from Roussillon, France. All have been used since prehistoric times, and are among the oldest pigments used.
When the mineral was found in Brixham England
, it became a very important part of the developing fishing industry. This gave the old fishing boats their "Red Sails in the Sunset
", but the purpose was to protect the canvas from seawater, not to be picturesque. It was boiled in great caldrons, together with tar
and oak bark
, the last ingredient giving the name of barking yards
to the places where the hot mixture was painted on to the sails, which were then hung up to dry.
- Fuller, Carl; Natural Colored Iron Oxide Pigments, pp. 281-6. In: Pigment Handbook, 2nd Edition. Lewis, P. (ed.). New York: John Wiley & Sons, 1988.
- Thomas, Anne Wall. Colors From the Earth, New York: Van Nostrand Reinhold, 1980.