Grumbacher Academy Watercolor - Gamboge Hue, 7.5 ml tube

Pigment Information

This color contains the following pigments:

PO62-Benzimidazolone Orange

PY138-Quinophthalone Yellow

PY65-Hansa Yellow

Pigment Name

PO62-Benzimidazolone Orange

Pigment Type

organic, monoazo

Chemical Formula

C17H13ClN6O5

Properties

Benzimidazolone Orange is a staining, yellowish orange pigment that can become dull in tints. It has an average drying time, and it loses some of its intensity as it dries. The yellowish orange varieties are more transparent.

Permanence

Benzimidazolone Orange has excellent lightfastness and outstanding heat and solvent stability for a monoazo pigment.

History

The benzimidazolone group of pigments was developed and patented in 1960 by Hoechst A.G., a German chemical manufacturer that was a forerunner of the pharmaceutical company Aventis. Use of benzimidazolone pigments in the auto industry, especially Benzimidazolone Orange, became common in the 1980s because they were common replacements for lead chromate pigments, which were phased out during this period.

Pigment Name

PY138-Quinophthalone Yellow

Pigment Type

organic synthetic, quinoline, vat

Properties

Quinophthalone Yellow is a transparent pigment classified as a vat pigment. It has high tinting strength and an average drying time.

Permanence

Quinophthalone Yellow has excellent lightfastness.

History

Unknown.

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.

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.