Rublev Colours Natural Yellow Oxide is from ocher deposits in the French quarries of Gargas and Rustrel nestled in a 12 mile long enclave in the heart of the Luberon Massif, the ocher country. It is a pigment of outstanding chemical stability and weather resistance. It is has moderate tinting strength, but is more opaque than yellow or gold ocher and has good covering power. Rublev Colours Aqueous Pigment 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, casein, fresco, watercolors and distemper (glue tempera). They are also ideally suited for use with gesso for making 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 and natural 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.
Rublev Colours Aqueous Dispersions make preparing traditional mediums easy; you do not have to hassle with powders, grinding pigments with expensive tools and calculating pigment-binder ratios to make water-based paint. They make adding the right amount of paint binder simple and easy. For example, preparing egg tempera has never been easier, because the dispersion makes measuring the right amount of pigment easy—you simply add egg and stir—there's no guessing how much egg to add to the pigment.
Origin and History
|Common Names: || English: yellow oxide |
French: oxyde juane
German: Oxid gelb
Italian: ossido giallo
Portuguese: óxido amarelo
Spanish: óxido amarillo
|Alternate Names: ||English: iron oxide, iron yellow, ocher, yellow ocher, yellow iron oxide |
French: oxyde jaune Indien
Mars yellow is the name given to the artificial substitute of natural yellow oxide.
Known since antiquity, yellow oxide occurs naturally as yellow ocher (limonite) or as red ocher (hematite). It has been used as a pigment since prehistoric times and is perhaps the most widely used pigment for artists' paints. Source
The composition of natural yellow oxide depends on the source, which is usually South Africa, India, France, Italy, Russia, and the United States. The best and most carefully washed and refined grades, according to Ralph Mayer, come from France [The Artist's Handbook
, p. 214]. Widely called yellow ocher or yellow earth, it is a clay colored by iron and produced in a number of yellow shades. Ocher is a natural earth composed of the natural mineral goethite, and traces of other minerals. Historically, yellow ocher was designated by the mineral name limonite. Limonite, however, is not a true mineral, but a general term used to describe all forms of hydrated iron oxide minerals (α-FeOOH) that occur as natural earth. Limonite includes the minerals goethite, akaganeite and lepidocrocite. The higher iron content, larger particles sizes can give darker, more opaque colors. Like red iron oxides (hematite), they are found around the world and have been used as pigments since prehistory. Permanence and Compatibility
Natural yellow oxide is 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
Natural yellow oxide absorbs a moderately high amount of oil. The oil absorption ratio is 30–35 parts by weight of raw linseed oil to 100 parts by weight of pigment. If the measurement were grams, the pigment would require 30–35 grams of raw linseed oil to grind 100 grams of pigment to form a stiff paste. It is average to slow as an oil paint, but forms a tough, flexible film. Toxicity
Natural yellow oxide is not considered toxic, but care should be used in handling the dry powder pigment to avoid inhaling the dust. Aqueous Pigment Dispersion: Natural Yellow Oxide
|Color: ||Yellow |
|Colour Index: ||Pigment Yellow 43 (77492) |
|Chemical Name: ||Iron Oxide Hydroxide |
|Chemical Formula: ||α-FeOOH |
|ASTM Lightfastness Rating |
|Acrylic: ||I |
|Watercolor: ||I |
|Density: ||2.9–4.3 |
|Hardness: ||4.0–5.5 |
|Refractive Index: ||2.260–2.398 |