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:
PY74—Hansa Yellow
Pigment Type
monoazo
Chemical Name
n/a
Chemical Formula
C18H18N4O6
Properties
Pigment PY74 is one of the most commercially important pigments of the Hansa Yellow group, considered superior to many others in its class based on both tinting strength and lightfastness. Several PY74 grades with different particle sizes are available. Grades with finer particle size are more brilliant and transparent. Pigment PY74 ranges from reddish yellow to greenish yellow, with temperature shifts from cool to warm hues. It has high tinting strength and average to slow drying time.
Permanence
This Hansa Yellow has better lightfastness that other yellow monoazo pigments, 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.
Alternate Names
Arylide, Arylide Yellow, Azo, Brilliant Yellow, Monoazo, Monolite Yellow, Permanent Yellow.
PR254—Pyrrole Red
Pigment Type
organic, aminoketone
Chemical Name
Bis-(p-chrolopheny)-1. 4-diketopyrrolo(3. 4-c)pyrrole
Chemical Formula
n/a
Properties
Pyrrole Red is opaque and has strong covering power. According to manufacturer Ciba, which uses the trade name Irgazin Red, it is a “clean, highly saturated mid shade red with high temperature resistance, excellent color strength, outstanding chemical, solvent and bleed resistance, and good weatherfastness.”
Permanence
Pyrrole Red is considered to have excellent lightfastness among organic pigments in its class. Tests in industrial applications have given it scores of 7-8 on the Blue Wool Scale.
Toxicity
According to the Australian government's Ministry on Health and Aging, "The notified chemical exhibited low oral and dermal toxicity in rats, did not exhibit toxic effects when administered orally to rats for 28 days, was not a skin irritant in rabbits, was not a skin sensitiser in guinea pigs, was not mutagenic in bacteria and was not clastogenic in CHO cells in culture. However, the notified chemical was a slight eye irritant in rabbits. On the basis of submitted data, the notified chemical would not be classsified as hazardous in accordance with Approved Criteria for Classifying Hazardous Substances."
History
Pyrrole Red, used as an automotive paint and as a colorant in plastics, was developed as one of a range of pigments to replace lead based pigments. In art materials, it is often used as a synthetic and lightfast replacement for carmine, a laked pigment that was originally produced from the body of the cochineal insect. It is also used to replace the older naphthol reds, organic red pigments that are sometimes only marginally lightfast and weatherfast.
Alternate Names
Magnacryl Red, Versal Red, Microlith Red, Unisphere Red, Cromophtol Red, Irgazin Red.
