Ercolano Red is a natural earth containing clay tinted by iron oxide that gives an exceptionally warm red hue. Our Ercolano red, like French ocher, contains at least 20% iron oxide and is low in silica. Ercolano red is obtained from iron ore deposits near Ercolano, 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
Ercolano Red is a red earth, which have been used as a pigment since prehistoric times and is perhaps the most widely used pigment for artists' paints.
Ercolano red is a red ocher obtained in the vicinity of Ercolano, named Herculaneum until 79 AD and Resina until 1969. Red ochers 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 (α-Fe2O3) that occur as natural earth. Depending upon the content of iron oxide and other minerals, the color of red ocher 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 ochers 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 ochers 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 ochers are not considered toxic, but care should be used in handling the dry powder pigment to avoid inhaling the dust. Aqueous Pigment Dispersion: Ercolano Red
|Pigment Information |
|Color: ||Red |
|Colour Index: ||Pigment Red 102 (77491) |
|Chemical Name: ||Iron Oxide |
|Chemical Formula: ||α-Fe2O3 |
|ASTM Lightfastness Rating |
|Watercolor: ||I |
|Density: ||147 lbs./ft3 |
|Hardness: ||5.5–6.5 |
|Refractive Index: ||4.8-5.26 |