Dr. Ph. Martin's Hydrus Fine Art Liquid Watercolors - Gamboge, 1 oz bottle

Pigment Information

This color contains the following pigments:

PR188 -Naphthol Red

PY65-Hansa Yellow

Pigment Name

PR188 -Naphthol Red

Pigment Type

organic monoazo

Chemical Formula

C33H24Cl2N2O6

Properties

This Naphthol Red is yellowish, with a high tinting strength and average drying time. It produces warmer shades and tints.

Permanence

This Naphthol Red has excellent lightfastness, though it is generally not considered adequate 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

Naphthol pigments are actually dyes that are "laked" to form pigments. First developed by the German chemical company Hoechst A.G. before World War I, their use in artist paints began in the 1920s.

Pigment Name

PY65-Hansa Yellow

Pigment Type

monoazo

Chemical Formula

C18H18N4O6

Properties

This Hansa Yellow ranges from reddish yellow to greenish yellow with temperature shifts from cool to warm hues. It has good tinting strength and average to slow drying time.

Permanence

This Hansa Yellow has excellent lightfastness, particularly in the darker shades.

Toxicity

Hansa Yellow has no significant acute hazards, though its chronic hazards have not been well studied.

History

Hansa Yellows were first made in Germany just before WW1 from a series of synthetic dyestuffs called Pigment Yellow. They were intended to be a synthetic replacement for Cadmium Yellow.