Gamblin 1980 Oils - PB28 Cobalt Blue (Cobalt(II) oxide + aluminum oxide); PB15:2 Phthalo Blue (Copper phthalocyanine)

Cobalt Blue: “True blue,” first manufactured in 1804. This colour is well worth the price because of its functional properties and unique colour, which cannot be mixed.

Pigmentandnbsp;Composition and Permanence:andnbsp;

Pigment Name: PB15:1 Phthalo Blue

Pigment Type: Organic

Properties

Phthalo Blue PB15:1 is a structural variant of Phthalo Blue PB15 that produces more reddish tones.

Permanence

Phthalo Blues are completely lightfast, stable, and permanent for all paint uses. Due to their stability, they are currently used in inks, coatings, and many plastics and are considered a standard pigment in printing ink and the packaging industry.

Toxicity

Phthalo Blues have no significant hazards, although those made before 1982 contained some PCBs (polychlorinated biphenyls).

History

Developed by chemists using the trade name Monastral Blue, the organic blue dyestuff, now known as Phthalo Blue, was presented as a pigment in November 1935 in London. Its discovery was accidental.

The dark colour was observed in a kettle where a dye was made from a British dyestuff plant. The demand for such a pigment came from commercial printers who wanted cyan to replace Prussian Blue.

andnbsp;

2ndandnbsp;Pigmentandnbsp;Composition and Permanence:andnbsp;

Pigment Name: PB28 Cobalt Blue

Pigment Type: inorganicandnbsp;

Properties

Cobalt blue is a semitransparent pigment with low to moderate tinting strength. When it dries, it appears lighter and less saturated. Pigment particles are large and grainy. Differences in how the pigment is ground and mixed lead to considerable differences in its performance among various manufacturers.

Permanence

Cobalt blue is absolutely lightfast and extraordinarily stable. Cobalt salts' stability at high temperatures makes them the standard for blues used in ceramics and glassware.

Toxicity

Cobalt salts are toxic. Avoid respiratory and skin contact. Soluble cobalt may cause irritation and allergic reaction through contact with skin. It is considered a possible carcinogen.

History

Since ancient times, smalt blue has been used to colour glass and ceramics. Cobalt salts, which give smalt its characteristic blue colour, were identified in the 18th century. Techniques for manufacturing Cobalt Blue, a chemically pure salt of cobalt and aluminum oxide, were developed in 1802.