Pebeo High Viscosity Acrylics - Raw Umber, 250 ml, Tube

Pigment Information

This color contains the following pigments:

PY42-Yellow Iron Oxide

PY83-Diarylide Yellow 83

PR22-Naphthol Red Brightf

PBk7-Lamp Black

Pigment Name

PY42-Yellow Iron Oxide

Pigment Type

Chemical Name

iron(III)-oxide, hydrated

Chemical Formula

Fe2O3 • H2O

Properties

Yellow Ochre provides artists with earthtones from cream to brown. It has good hiding power, produces a quick drying paint, and can be safely mixed with other pigments. Its transparency varies widely from opaque shades to more transparent ones, which are valued for their use as glazes. If gypsum is present, Yellow Ochre is not suitable for frescoing. (See Brown Ochre, PY43.) PY42 is made from synthetic iron oxides. PY43 is made from natural iron oxide.

Permanence

Yellow Ochre has excellent permanence because ochres are some of the most permanent pigments available.

Toxicity

Yellow Ochre is non-toxic unless it contains manganese.

History

Ochre comes from the Greek word ochros, meaning pale yellow. It was one of the first pigments to be used by human beings, and evidence of its use has been found at 300,000 year old sites in France and the former Czechoslovakia.

Pigment Name

PY83-Diarylide Yellow 83

Pigment Type

organic, disazo

Chemical Formula

C36H32Cl4N6O8

Properties

Diarylide Yellow is a semi-opaque, moderately staining, intense deep reddish yellow pigment with good tinting strength.

Permanence

Diarylide Yellow 83 has very good lightfastness and permanence. However, it can fade in tints, so some artists do not consider it suitable as an artists' color. Many other diarylide yellow pigments are reported to have fair to poor lightfastness, and some are completely fugitive. Diarylide Yellow 83 is reputed to be one of the most permanent of the entire group.

Toxicity

Diarylide Yellow has no significant acute hazards, but chronic hazards have not been well studied.

History

Diarylide Yellow comes from a family of azo pigments called Diarylide. These yellow hued pigments were developed around 1940 and are very important in printing inks.

Pigment Name

PR22-Naphthol Red Brightf

Pigment Type

organic

Chemical Name

3-hydroxy-4-(2-methyl-5-nitrophenyl)azo-N-phenylnaphthalene-2-carboxamide

Chemical Formula

C24H18N4O4

Properties

Bright, bluish shade red

Permanence

Naphthol Reds vary widely in lightfastness. This Naphthol Red (PR146) has fair to poor permanence and always fades in tints. It is not suitable for outdoor use.

Toxicity

Naphthol Reds are not considered toxic. They may cause eye, skin, or respiratory irritation. Contact with dry pigment should be avoided.

History

Unknown.

Pigment Name

PBk7-Lamp Black

Pigment Type

inorganic

Chemical Name

carbon

Chemical Formula

C

Properties

Lamp black is a very opaque, heavily staining black pigment that does not have much covering or tinting power. It is typically the most opaque black in watercolor form. Though a very pure black, it tends to muddy slightly in mixtures. Natural sources may be brownish or bluish in tone because of impurities. When used in oil paints, it is one of the slowest drying pigments, and should not be used in underpainting or applied in layers underneath other colors.

Permanence

Lamp Black is very lightfast and absolutely permanent. It is used in all techniques in permanent painting.

Toxicity

Carbon itself is not considered hazardous, however other combustion products that are hazardous are often present as impurities when Lamp Black is produced from natural materials. For this reason, commercial preparations of the pigment should be considere

History

Lamp Black is a carbon based black traditionally produced by collecting soot (known as lampblack) from oil lamps. It has been used as a pigment since prehistoric times. It is the black found in Egyptian murals and tomb decorations and was the most popular black for fresco painting until the development of Mars Black.