Burnt umber
Composition and Properties of Burnt Umber
Umber is a general designation for a sedimentary mineral substance containing between 5 to 20% manganese oxides and hydroxides and a larger percentage of iron oxides. The higher content of manganese oxides compared to ochres is responsible for the brownish colour. The calcinating or burning corresponds to heating the material with the purpose of removing water molecules from the crystal structure. This procedure results in a shift of the colour towards warm brown.Iron oxides can withstand high temperatures but are not resistant to acids. The pigment is stable although there were reports on changing colour over time during the Renaissance period. It is compatible with all other pigments and is often used to darken other pigments in shadows.
Names
Mineral brownPBr 7, CI 77492From Middle French ombre (in terre d’ombre), or Italian ombra (in terra di ombra), both from Latin umbra “shade, shadow” From Online Etymology Dictionary
Preparation
Umber can be found in nature with the largest deposits in Cyprus. Burnt umber is prepared by heating raw umber until it is a reddish-brown color.
History of Use
The pigment had been in use since antiquity.Examples of use
Quote
I work like a gang of slaves; the day seems five months long. My wish to make a winter landscape has become a fixed idea. I want to do a sheep picture and have all sorts of projects in my head. If you could see how beautiful the forest is! I rush there at the end of the day, after my work, and I come back every time crushed. It is so calm, such a terrible grandeur, that I find myself really frightened. I don't know what those fellows, the trees, are saying to each other.. ..we don't know their language, that is all; but I am quite sure of this - they do not make puns!.. ..Send [me] 3 burnt sienna, 2 raw ditto, 3 Naples's yellow, 1 burnt Italian earth, 2 yellow ocher, 2 burnt umber, 1 bottle of raw oil. Quote of Millet, in his letter from Barbizon, c. 1850 to fr:Alfred_Sensier in Paris; as cited by Arthur Hoeber in The Barbizon Painters – being the story of the Men of thirty – associate of the National Academy of Design; publishers, Frederick A. Stokes Company, New York 1915, p. 38 In 1850 Millet entered into an arrangement with Alfred Sensier, who provided him with materials and money in return for drawings and paintings (source: Murphy, Alexandra R. Jean-François Millet. Museum of Fine Arts, Boston, 1984, p. xix), see: Wikipedia, Millet
Source: Jean-François Millet
