Popular Pigment Colours

Lamp black

Traditionally lamp black was made from soot collected from oil lamps. This is chemically known as amorphous carbon, because it is not bonded to form the naturally occurring carbon allotropes, graphite and diamond. Amorphous carbon reflects very little light, so lamp black and ivory black are darker that mars black.

Ivory black

Historically ivory black was made from the charring of ivory and bone, and is chemically very similar to lamp black.

Mars black

Mars black is different in that its pigment is synthesized Iron oxide. Iron oxides tend to form reddish-brown pigments which are used in colours such as ochres, siennas and umbers. Therefore, mars black is not as dark as those pigments containing amorphous carbon suspensions.

Process black

Process black is formulated to mimic the black (represented by K in ‘CMYK’) as used in printing. It is popularly used with other process colours available, such as process cyan, process magenta and process yellow.

Titanium white

Titanium dioxide. This paint has a high opacity and is good for lightening colours.

Zinc white

Zinc oxide. This paint is less opaque than that containing Titanium dioxide, and mixes better (though it may require more paint).

Mixing white

TnO2/ZnO. This paint is a compromise of the previous two types, where immiscibility is overcome by the addition of the Zinc compound at the expense of the excellent tinting obtained through using TnO2 alone.

Flake white

Flake white is a by-product of electrolysis, where lead electrodes are used. White lead salts build up and, due to their shape, literally flake off, hence the name. Lead-based paints are becoming increasingly less popular due to the danger inherent in using them.  Assuring that appropriate precautions are taken, lead-based paints can be used safely.  Many artists, however, choose safer alternatives in order to avoid any risk.  Zinc oxide and Titanium dioxide are common replacement pigments.

Genuine Pigments and Hues

Paints described as ‘artists’ colours’ are pigmented with genuine pigments. For example, Cadmium reds and yellows contain Cadmium compounds, and Cobalt blues and violets contain Cobalt. Artists’ paints tend to be divided into series, with ‘1’ or ‘A’ containing the cheapest-to-produce pigments, ‘2’ or ‘B’ containing a more-expensive pigment, and so on.

Colour Pigment

Cadmium red Cadmium sulphoselenide

Cobalt blue Cobalt aluminate

Some metal compounds, such as those containing Cadmium and Cobalt are metabolic poisons, although this is not mentioned on the health labeling. Appropriate care should be taken when using this paint and disposing of materials. Other compounds, such as amorphous carbon, found in lamp and ivory black, are carcinogenic, though few pigments are dangerous when used normally. Extra precautions need to be taken when using genuine flake white, on account of it containing lead.

Hues use alternative pigments blended to give as similar a shade as possible. The pigments used may be synthetic and may be less resistant to fading and are often considered inferior to artists’ colours. However, these ‘student’ paints usually fall into one price category.  Hues are popular as replacements for paints whose pigments contain toxic chemicals.

Where several alternative pigments are used, separation may occur during use, leading to a colour shift upon drying. On the other hand, the different pigments used can display other benefits, such as increased miscibility. Hues are cheaper to produce, and tend to appear in manufacturers’ ‘student’ ranges, such as Winsor and Newton’s ‘Galeria’, ‘Cotman’ and ‘Winton’ ranges, and Daler Rowney’s ‘Georgian’, ‘Aquafine’ and ‘System 3’ ranges. They offer a cheaper alternative for beginners and students.  Some student ranges such as Galeria have added genuine pigment colours to their range.

Some colours contain the same pigments regardless of whether they are in the artists’ range or the budget range. ‘Earth tones’ such as yellow ochre, raw and burnt sienna and raw and burnt umber are pigmented with various types of Iron oxide, which may be synthetic, or naturally obtained. Iron-containing paints are cheaper to produce owing to the presence of iron in common minerals and ores. Iron compounds are also stable, and therefore colours derived from them are resistant to fading. Synthetic Iron oxide is used in both artists’ and students’ colours.

With thanks to Paul Robinson, Technical Advisor, Winsor & Newton for additional material.

Colour Pigment(s)

Cadmium red (hue) Napthol AS, Napthol carbamide
Cobalt blue (hue) Ultramarine, Lithopone, Copper phthalocyanine
Raw sienna (Winton) Natural Iron oxide (veh. linseed oil)
Raw sienna (Artists’ oil) Natural Iron oxide (veh. linseed/safflower oil)
Light red (Winton) Synthetic Iron oxide (veh. linseed oil)
Light red (Artists’ oil) Natural Iron oxide (veh. linseed/safflower oil)