Perylene Red is a moderately intense, semi-opaque, medium red pigment, appearing somewhere between a Cadmium Red and a Cadmium Deep Red hue. It has excellent brightness and tinting strength. Its partial transparency makes it useful as a glazing color.
Perylene Red has good lightfastness and permanence. Its tints may darken after extended exposure to sunlight. It is not considered suitable for exterior use.
Perylene Red has no significant acute toxicity. Its long term hazards are currently unknown.
Perylenes have been used as vat dyes since 1912, but they were not manufactured and sold as pigments until 1957. For artists, they are a replacement for historic colors that were made with berries, and are significantly more lightfast.
PR101-Red Iron Oxide
iron oxides (synthetic), iron oxide, silica, alumina, lime, and magnesia or hydrated iron oxide
Fe2O2 or Fe2O3 x H2O
Red iron oxide varies in hue and transparency, depending on hydration and slight impurities. Indian Red is a slightly duller, deep brick hue with a bluish undertone. It is very dense and opaque, with excellent tinting strength and covering power. It is dependable when mixing with all other permanent pigments and yields good flesh tints when mixed with Zinc White. It is the synthetic version of PR102, which is a pigment made from earth reds, or natural red iron oxides, and the names applied to PR101 and PR102 often overlap. The synthetic red iron oxides have mostly replaced natural red iron oxides and are brighter, stronger, finer, and more permanent. Indian Red is the highest grade bluish shade. Light Red, English Red, and Venetian Red are yellowish shades. Mars Violet is a dull and subdued bluish or purplish oxide.
Red iron oxide is very lightfast with excellent permanence.
Red iron oxide has no significant hazards.
Natural red iron oxide comes from the mineral ore hematite, called bloodstone by the ancient Greeks from the word hema, meaning blood. It is one of the oldest pigments, has been used by every major civilization, and was an important mineral for medieval alchemists. It was not widely used in artists' materials until the 17th century and was not produced in large quantities until the 18th century.