Red ocher
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Description
Any of several naturally occurring red earth pigments. Red ochers contain Hematite (red iron oxide) mixed with clay and vary widely in hue. Ground finely from red earth or clay, red ochers are lightfast, unreactive pigments that have been used since ancient times. They can also be manufactured by calcining Yellow ocher (Goethite).
Synonyms and Related Terms
red ochre (Br.); red earth; earth red; iron oxide red; red iron oxide; Indian red; brun rouge; Roter Ocker (Deut.); minium de fer (Fr.); reddle; Spanish brown; Venetian red, English red; Spanish red; caput mortuum; Indian red; light red; burnt sienna
Physical and Chemical Properties
| Composition | Fe2O3 |
|---|---|
| Mohs Hardness | 5.5 - 6.5 |
| Density | 4.2-5.3 g/ml |
| Refractive Index | 2.78; 3.01 |
Resources and Citations
- Helen Howard, Submitted information, November 2007
- R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966
- Reed Kay, The Painter's Guide To Studio Methods and Materials, Prentice-Hall, Inc., Englewood Cliffs, NJ, 1983
- Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
- R.D. Harley, Artists' Pigments c. 1600-1835, Butterworth Scientific, London, 1982
- Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982
- Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
- Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000
- Pigments Through the Ages http://webexhibits.org/pigments/indiv/overview/redochre.html
- The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996 Comment: "Pigments"
Record content reviewed by EU-Artech, November 2007.