Rublev Colours Pigment Cobalt Aluminate Blue - 100 g

Water-Based Paint

Cobalt Aluminate Blue is a semi-transparent pigment with moderate tinting strength in most water-based paints. When it dries, it appears lighter and less saturated. Although pigment particles are very fine, they flocculate, giving a grainy appearance in watercolor. Differences in how the pigment is ground and mixed lead to considerable differences in its performance.

Oil-Based Paint

Cobalt Aluminate Blue is a semi-transparent pigment with moderate tinting strength in oil-based paint. Differences in how the pigment is ground and mixed can lead to considerable differences in appearance.

This pigment has exceptional durability and hiding power and is generally used in applications where resistance to heat, light, and weather is needed. It is compatible with most resin systems and polymers and is non-warping. Typical applications include liquid and powder coatings, inks, dispersions, concrete, plastics, and other applications where equivalent pigment chemistry is used.

Cobalt Aluminate Blue absorbs a moderately high amount of oil, about 34 grams of linseed oil per 100 grams of pigment, to make a paste. It has been noted in some manuals that the pigment works better as a watercolor than it does in oil and is highly valued on that account among moist colors used by artists. Grinding it for artists' use in oil will require about 70 percent dry pigment to 30 percent by weight of poppy seed or walnut oil, either of which some artists prefer to linseed oil. Cobalt chromite blue has a greenish tone that is more or less reddish blue when viewed under incandescent light.

Cobalt Aluminate Blue is made by calcining at 2400°F a mixture of cobalt (II) oxide, chromium (III) oxide, and aluminum (III) oxide in varied ratios, forming an interdiffused crystalline spinel matrix. Its constitution may also include one or more modifiers, zinc oxide (ZnO), manganese oxide (MgO), silicon dioxide (SiO₂), titanium dioxide (TiO₂), or zirconium dioxide (ZrO₂) to adjust color hue or other properties. Cobalt blue pigments are the most durable blue pigments commercially available. They have excellent chemical and heat stability and can be used in chemically aggressive environments and exterior durable applications without color fade.

This pigment is easily dispersed, does not need grinding, and can be stirred using most laboratory and production equipment to achieve complete dispersion.

Cobalt Aluminate Blue is not considered toxic; however, care should be taken when handling the dry powder pigment to avoid inhaling the dust. All toxicological studies showed no signs of toxicity to humans or the environment.

In animal studies, cobalt blue pigments did not display acute toxicity. No acute irritant effect was shown in tests to determine the acute irritation of skin and mucous membranes. No statistically significant results were found in studies on rats to determine the carcinogenic potential. Soluble cobalt compounds and cobalt metals may have a sensitizing effect. However, none have been reported during many years of handling cobalt blue pigments.