Sartorius red earth is a natural mineral containing clay tinted by iron oxide that gives an exceptionally warm orange-red hue. Our Sartorius red earth is from mineral deposits in the Tuscany region of Italy.
Rublev Colours Aqueous Dispersions are pigments dispersed in water ready to be mixed with water-based mediums. These dispersions are especially made for use with traditional painting mediums, such as egg tempera, casein tempera, fresco, watercolors and distemper (glue tempera). They are also ideally suited for use with gesso to make toned grounds for drawing and painting. Pigment dispersions from Rublev Colours contain only naturally-derived ingredients, in addition to pigment and water, making them ideally suited for traditional mediums. Unlike other pigment dispersions that are typically made for acrylic medium, Rublev Colours Aqueous Dispersions do not contain coalescent solvents, artificial dispersing resins and other additives that interfere with natural mediums. Aqueous Dispersions make preparing traditional mediums easy; you do not have to hassle with powders, grinding pigments in medium and calculating binder ratios to make water-based paint. They make adding the right amount of paint binder, such as egg yolk, a no brainer because the right amount of water is already contained in the dispersion, simply add egg yolk.
|Pigment Names |
|Alternate Names: ||Mars Red is the name given to the synthetic precipitated form of iron oxide. |
Origin and History
Sartorius red earth is a red earth from Italy based on the mineral hematite. The word hematite comes from the Greek word hema, meaning blood and was given the name "bloodstone" in ancient Greece (Theofrastus, c. 325 B.C.), implying that the mineral is blood red in color. Hematite is an important ore of iron and its blood red color in the powdered form lends itself well as a pigment. Red earths, including the mineral hematite, are among the oldest pigments known to humankind and has been used by every major civilization and epoch.
Red ochres are natural earths containing clay tinted by iron oxide and is composed of hematite, and traces of gypsum (calcium sulfate) or calcite (calcium carbonate). Hematite is a mineral composed of iron oxide minerals (á-Fe2O3) that occur as natural earth. Depending upon the content of iron oxide and other minerals, the color of red ochre varies from deep red to brownish red. Red iron oxide minerals, such as hematite, are found around the world and have been used as pigments since prehistory.
Permanence and Compatibility
Red ochres are among the most permanent colors among the artist's palette. It is compatible with all other pigments, and can be used with good results in all mediums.
Oil Absorption and Grinding
Red ochres absorb a medium amount of oil, which may slow the drying of oil paint, but because iron oxide is a drier in oil, it dries fast and forms an excellent film.
Red ochres are not considered toxic, but care should be used in handling the dry powder pigment to avoid inhaling the dust. Aqueous Dispersion: Red Sartorius Earth
|Pigment Information |
|Color: ||Red |
|Colour Index: ||Pigment Red 101 (77491) |
|Chemical Name: ||Iron Oxide |
|Chemical Formula: ||á-Fe2O3 |
|ASTM Lightfastness Rating |
|Acrylic: ||I |
|Oil: || |
|Watercolor: ||I |
|Density: ||2.9–4.3 |
|Hardness: ||4.0–5.5 |
|Refractive Index: ||2.260–2.398 |