Ochre or Ocher (pronounced OAK-ur, from the Greek ochros, yellow) is a color, usually described as golden-yellow or light yellow brown.
Authors of web pages have a variety of options available for specifying colors for elements of web documents. ... The RGB color model utilizes the additive model in which red, green, and blue light are combined in various ways to create other colors. ... Cyan, magenta, yellow, and key (black) CMYK (or sometimes YMCK) is a subtractive color model used in color printing. ... The HSV (Hue, Saturation, Value) model, also called HSB (Hue, Saturation, Brightness), defines a color space in terms of three constituent components: HSV color space as a color wheel Hue, the color type (such as red, blue, or yellow): Ranges from 0-360 (but normalized to 0-100% in some... Colour is an important part of the visual arts. ...

Pigment

Goethite (brown ochre)

As a painting pigment it exists in at least three forms: Goethite (brown ochre) From an email dated Wed, 31 Mar 2004 21:25:29 -0800: You can use the images of pigments as long as you give full credit to Iconofile and the web site. ... Goethite (brown ochre) From an email dated Wed, 31 Mar 2004 21:25:29 -0800: You can use the images of pigments as long as you give full credit to Iconofile and the web site. ... The Mona Lisa is perhaps the best-known artistic painting in the Western world. ... In biology, pigment is any material resulting in color in plant or animal cells which is the result of selective absorption. ...

• yellow ochre, Fe₂O₃ • H₂O, a hydrated Iron oxide
• red ochre, Fe₂O₃, chemically identical to yellow ochre, but reddened through heating
• brown ochre (Goethite), also partly hydrated iron oxide (rust)

For further information, see the articles on the individual ochres. Red ochre and yellow ochre (pronounced OAK-ur, from the Greek ochros, yellow) are pigments made from naturally tinted clay. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Hydrates are compounds formed by the union of water with some other substance, generally forming a neutral body, as certain crystallized salts. ... Iron oxide pigment There are a number of iron oxides: Iron oxides Iron(II) oxide or ferrous oxide (FeO) The black-coloured powder in particular can cause explosions as it readily ignites. ... Red ochre and yellow ochre (pronounced OAK-ur, from the Greek ochros, yellow) are pigments made from naturally tinted clay. ... Goethite is a hydrated iron oxide, HFeO2 or Fe3+O(OH) (known as lepidocrocite). ... Iron oxide pigment There are a number of iron oxides: Iron oxides Iron(II) oxide or ferrous oxide (FeO) The black-coloured powder in particular can cause explosions as it readily ignites. ... Rusted cars The rusting can completely eat away iron Rusted screw A blacksmith removing rust with sand prior to welding Rust is the substance formed when iron compounds corrode in the presence of water and oxygen. ...

All ochres are non-toxic, and can be used to make oil paints that dry quickly and cover surfaces thoroughly. 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 are prehistoric, and are some of oldest pigments used. A toxin, in a scientific context, is a biologically produced substance that causes injury to the health of a living thing on contact or absorption, typically by interacting with biological macromolecules such as enzymes and receptors. ... Roussillon is a village and commune in the Vaucluse département of southern France. ...

See also

• clay earth pigment
• List of colors

Clay earth pigments are naturally occurring minerals that have been used since prehistoric times as pigments. ... The following is a partial list of colors with associated articles. ...

Further reading

• Red Ochre, Yellow ochre, and Brown ochre, from Pigments through the ages.
• 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.