Roman Black Dispersion

Roman Black is a natural black earth that is a dense, opaque, heavy color that is absolutely permanent. It is comparatively neutral in undertone, wets easily, and is non-greasy compared to carbon blacks. It is a valuable pigment when these qualities are required. Writers like De Mayerne mention the black earths of Rome and Venice. Roman black earth (Terra nera di Roma) is described by Salter as producing ‘the same effect as charcoal black.’ It is warm to neutral in undertone, wets easily, and is non-greasy compared to carbon blacks. It is a valuable pigment when these qualities are required.

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, pigment, and water, making them ideally suited for traditional mediums. Unlike other pigment dispersions typically made for acrylic mediums, Rublev Colours Aqueous Dispersions do not contain coalescent solvents, artificial dispersing resins, or 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 mediums, and calculating binder ratios to make water-based paint. They make adding the right amount of paint binder, such as egg yolk, is a no-brainer because the right amount of water is already contained in the dispersion; simply add egg yolk.

Origin and History

Black oxide is a recent development in modern pigments and was not often encountered in artists’ palettes before the 19th century. However, black earths that are mixtures of iron oxide, manganese oxide, and carbon have been in use since Antiquity.

Source

Natural black oxide is usually from an iron ore called magnetite. Magnetite, or lodestone, is a ferrous ferric oxide that is heavy, black, and opaque. Theoretically, black iron oxide contains slightly more iron metal than red oxide but not nearly as much as yellow oxide. The native mineral may contain varying amounts of manganese, clay, and silica.

Permanence and Compatibility

Natural black oxide is a permanent color for all uses on 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 black oxide absorbs a moderately low amount of oil. The oil absorption ratio is 20–25 parts by weight of linseed oil to 100 parts by weight of pigment. If the measurement were grams, it would require 20–25 grams (by weight) of linseed oil to grind 100 grams (by weight) of pigment to form a stiff paste. It makes an average drying oil paint and forms a hard, somewhat flexible film.

Toxicity

Natural black oxide is not considered toxic, but care should be taken when handling the dry powder pigment to avoid inhaling the dust.

Rublev Colours Pigment: Roman Black