Grumbacher Academy Oil Color - Permanent Green Light, 37 ml tube

Pigment Information

This color contains the following pigments:

PY35-Cadmium Yellow

PY65-Hansa Yellow

PB15:3-Phthalo Blue

Pigment Name

PY35-Cadmium Yellow

Pigment Type

inorganic, cadmium

Chemical Name

cadmium zinc sulfide

Chemical Formula

CdZnS

Properties

Cadmium Yellow is brilliant, dense, and opaque, with good tinting strength and very high hiding power. It is the artist's principal bright yellow and is available in light, medium, and dark shades. The deeper shades appear deep orange and have the greatest tinting strength. It is slow-drying in oil form and is used in both oil and watercolor form. A clean Cadmium Orange is created when Cadmium Yellow is mixed with Cadmium Red. Hues vary by brand. Cadmium pigments have been partially replaced by azo pigments, which are similar in lightfastness to the cadmium colors, cheaper, and non-toxic. Cadmium Yellow is usually available in a pure grade, or in a cadmium-barium mix. This mix has the same permanence with a lower tinting strength.

Permanence

Cadmium Yellow is lightfast and permanent in most forms, but like most cadmium colors, it will fade in fresco or mural painting. The deeper shades are the most permanent. The pale varieties have been known to fade with exposure to sunlight in conditions where moisture is able to penetrate the binder.

Toxicity

Cadmium Yellow is a known human carcinogen. It can be hazardous if chronically inhaled or ingested.

History

Cadmiums get their names from the Latin word cadmia meaning zinc ore calamine, and the Greek word kadmeia, meaning Cadmean earth, first found near Thebes, the city founded by the Phoenician prince Cadmus. Metallic cadmium was discovered in 1817 by Friedrich Strohmeyer. Oil colors were first made from Cadmium Yellow pigments in 1819, replacing toxic Chrome (lead) Yellows. However, their production was delayed until 1840 due to the scarcity of cadmium metals. Landscape painters, such as Claude Monet, preferred Cadmium Yellow to the less expensive Chrome Yellow because of its higher chroma and greater purity of color.

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.

Pigment Name

PB15:3-Phthalo Blue

Pigment Type

organic

Chemical Name

beta copper phthalocyanine

Chemical Formula

C32H16CuN8

Properties

Phthalo Blue PB15:3 is a structural variant of Phthalo Blue PB15 that produces more greenish tones.

Permanence

Phthalo Blues are completely lightfast and stable and are permanent for all paint uses. They are currently used in inks, coatings, and many plastics due to their stability 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 color was observed in a kettle where a dye was being made from a British dyestuff plant. The demand for such a pigment came from commercial printers who wanted a cyan to replace Prussian Blue.