Ochre
Ocher (from Greek ὠχρός " pale, pale yellow " ) are earth tones, namely mixtures of 5-20 % limonite with clay minerals, quartz and limestone.
As a pigment it is as yellow ocher (Schön yellow) used in diverse varieties and shades, red ocher, red ocher or brown ocher, brown ocher in painting. The yellow varieties are also divided according to the color in light ocher, yellow ocher, gold ocher, flesh ocher, ocher satin ( orange ocher, satin upper ). By heating pigments are yellow in red converted and then described as burnt ocher.
As a color name, however, is valid only ochres for less color- saturated yellows, against the reddish Siena and the grünlichere Umbra. As a web color corresponds with that of goldenrod (English " goldenrod " ) designated group. Other color names are Sienna or Schönbrunn yellow.
Color loci
For the French ocher, a letter code has prevailed, describing their quality:
- J - yellow / yellow, R - red / red, B - brune / brown
- T - très very
- C - claire / light ( translucent ), F - fonce / dark ( more opaque varieties ), O - or / gold yellow
- L - Lavée / washed, E - extra, S - super
So is about:
- Lights ocher JTCLES - watercolor painting a healthy and beautiful, not to bright yellow
- Gold Ochre Joles - the color corresponds to the Baroque Yellow
Mine ocher or ocher resin, however, is a basic iron (III ) sulfate, gold satin top is a yellow-tinged commercial grade of red lead (lead (II, IV ) oxide ).
Yellow ocher
The natural yellow ocher is named differently according to its origin: French Ochre JL (the classic pigment), Terra di Siena (Italian ocher, sienna ), Cyprischer ocher ( a particularly fine variety bright ocher ), Bohemian ocher (the actual Schönbrunn yellow ) Derbyshire ocher, ocher Lusatian, Amberger yellow.
The artificial variant and embellished with iron oxide yellow varieties are also known as Mars yellow (like the yellow iron oxide itself).
The main ingredient of yellow ocher, the iron (III ) oxide hydrate (Fe2O3 · n H2O - limonite limonite ).
Red ocher
The coloring principle in the red ocher (also called " red chalk ") is the iron (III ) oxide, hematite ( Fe2O3). Typical varieties are French Ochre RL, Burgundy ocher, ocher English pit. As with all natural earth pigments is they also find shares of clays and quartz. The red ocher can also win by firing yellow ocher ( ocher or burnt sienna, burnt, burning see limonite ).
Brown ocher
As Brown Ochre little colorful varieties are referred to in which the Brown impression outweighs the yellow or reddish.
These are natural occurrences with admixtures of about manganese oxides and hydrates that are close to the umbra to or similar to goethite baked color means burned in their appearance of the umbra or other little colorful fired iron oxide pigments.
Use
All ocher are to use in each binder (provided the necessary purity) absolutely lightfast, weather-resistant and compatible with all other pigments.
History
Ochre has been playing in the Middle Stone Age of South Africa a role as a color for decoration of jewelry worm or as body jewelry. Also in the European Palaeolithic cave painting ocher was used. The scattering of red ocher has been the Gravettian to the Magdalenian a typical feature of tombs.
In antiquity and the Middle Ages include the ocher world for basic palette of all colored media of the arts.
Extraction
The most famous place of decomposition in Europe are the ocher quarries in the French resort of Roussillon in the Vaucluse. Famous for its very good quality was the gold ocher, with its exquisite color, the typical baroque yellow. An impressive, also derelict mining area is located about 20 km east of Roussillon in Colorado at Bouvène, south of rustrel. These occurrences have been used in Roman times, but then forgotten and only rediscovered in 1780.
Mining and sale of French ocher is managed by the Société des Ocres de France ( SOF). In Germany, among others, won in Goslar on the northern edge of the Harz ocher from settling tanks ( " ocher marshes "), which clarified the mine waters of Rammelsberg mining. Also in the Upper Palatinate was recovered to about 1920 around the town of Neukirchen bei Sulzbach -Rosenberg ocher in mining, which has been further processed in a paint mill to paint.
A well-known Australian mining area is Wilgie Mia in Perth.
Today ocher is obtained almost exclusively in small amounts of soil through lengthy Ausschlämmverfahren. Here, the pigment is washed in a series of settling tanks and cleaned in Windmills of fiber. This raw material is then dried. If necessary, it is then brought to the desired hue by a firing process. In addition, particularly color beautiful " nests " (small, concentrated accumulations ) are specifically utilized for the artist and restoration needs.
By far the most ocher but is now produced on an artificial basis. To iron oxide colors are coated on a suitable substrate.
Ocher cliffs at Roussillon
Ocher cliffs at Roussillon
Ocher rocks at rustrel