Color Swatch created using heavy application/diluted application and was applied on cold press watercolor paper (150 lb) material.
This color contains the following pigments:
PB28—Cobalt Blue
Pigment Type
inorganic
Chemical Name
cobalt(II) oxide + aluminum oxide
Chemical Formula
CoO + Al2O3
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. The stability of cobalt salts at high temperatures make 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 color glass and ceramics. Cobalt salts, which give smalt its characteristic blue color, were identified in the 18th century. Techniques for manufacturing Cobalt Blue, a chemically pure salt of cobalt and aluminum oxide, were developed in 1802.
Alternate Names
Smalt Blue
PR9—Naphthol Red
Pigment Type
monoazo
Chemical Name
n/a
Chemical Formula
C24H17Cl2N3O3
Properties
This Naphthol Red is a bright deep red with bluish undertones. It has an average drying time.
Permanence
This Naphthol Red has fair to good lightfastness, not because of its masstone, but because it fades in tints. Not suitable for exterior use.
Toxicity
Naphthol Reds are not considered toxic. They may cause eye, skin, or respiratory irritation. Contact with dry pigment should be avoided.
History
Unknown.
Alternate Names
Naphthal, Naphthol Bordeaux, Naphthol Carbamide, Naphthol Carmine, Permanent Carmine, Permanent Red.
