Roussillon - Ochre

Photo prise à : Roussillon, Vaucluse

Ochre Ochre or ocher (pronounced /ˈoʊkər/ OH-kər, from the Greek ὠχρός, ōkhrós, pale) is the term for both a golden-yellow or light yellow brown-- color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues. Because of these other hues, the color ochre is sometimes referred to as "yellow ochre" or "gold ochre". Ochres are among the earliest pigments used by mankind, derived from naturally tinted clay containing mineral oxides. Chemically, it is hydrated iron (III) oxide. Modern artists' pigments continue to use the terms "yellow ochre" and "red ochre" for specific hues. Ochres are non-toxic, and can be used to make an oil paint that dries quickly and covers surfaces thoroughly. To manufacture ground ochre, ochre clay is first mined from the ground. It is then washed in order to separate sand from ochre, which can be done by hand. The remaining ochre is then dried in the sun and sometimes burned to enhance the natural color. As a painting pigment, it exists in at least four forms: Yellow ochre, Fe2O3 • H2O, a hydrated iron oxide, also called Gold ochre 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) 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.

portes, houses, facade, couleur, Roussillon, ocre, maison, France, Vaucluse, Provence

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