Material & Techniques

Extreme care is required when handling pigments whether in paint tubes or in dry powder form. Pigments can enter through the skin, mouth, and nose—causing serious injuries and sometimes irreparable damage. The toxicity or hazard level of pigments varies according to how it gets into the body. A pigment that is considered non-toxic when coming into contact with the skin may turn highly toxic when ingested or inhaled.

An artist should check the label and do further research to determine the toxicity or potential health hazards of the pigments in their colour palette. A pigment considered extremely/highly toxic will cause serious injuries when a small amount gets into the body through absorption, ingestion, or inhalation. A pigment considered moderately toxic will cause minor injuries - whether permanent or temporary - when it gets into the body. A pigment considered slightly toxic will result in temporary minor injuries. A non-toxic pigment means no detectable injury will result when small quantities get into the body; however, it does not mean safe or non-hazardous. An accumulation of non-toxic pigment in the body over time can still result in some injuries. Age and physical conditions will determine how effectively the body can counter the accumulation.

Pigments containing heavy metals such as antimony, barium, cadmium, chromium, cobalt, copper, lead, manganese, strontium, and zinc are highly toxic. Pigments that do not contain heavy metal pigments are considered non-toxic but must still be treated with caution. Paints described as 'hue', such as "cadmium red hue", indicate that there is no (or negligible amount of) toxic metal contained in the product.

The following pigments contain some level of toxicity and should be handled carefully.

Alizarin Crimson, Anthraquinone, Antimony Black, Antimony White, Barium Yellow, Burnt Umber, Cadmium Barium Yellow, Cadmium Red, Cadmium Orange, Cadmium Vermilion Red, Cadmium Yellow, Carbon Black, Cerulean Blue, Chrome Green, Chrome Orange, Chrome Yellow, Chromium Oxide Green, Cobalt Blue, Cobalt Green, Cobalt Violet, Cobalt Yellow, Emerald Green, Flake White, Lithol Red, Lead White, Manganese Blue, Manganese Violet, Molybdate Orange, Naples Yellow, Prussian Blue, Raw Umber, Paris Green, Smalt, Strontium Yellow, Toluidine Red, Vermilion, Viridian, Zinc White, Zinc Yellow.

The use of turpentine in the studio increases the risks of absorption through the skin because they act as a vehicle to carry the pigment into the body which would not otherwise pass. It is a little-known fact that in the nineteenth century, turpentine was used as a liniment to carry herbs into the body through the skin.

Artists who feel they are only being exposed to small quantities of pigments may adopt a lackadaisical attitude towards the risks of pigment poisoning. That is imprudent because injuries can still occur from repeated absorption, albeit in small quantities. A prudent artist will treat all pigments as hazardous or potentially hazardous and take the necessary precautions.

The egg tempera painting technique is more than several centuries old. Egg tempera paint is water-soluble and fast-drying. A thin layer of paint can dry within minutes into a translucent film. It's generally not as transparent as watercolours or as opaque as gouache but can be made to appear so with the right mixture, technique, and application. Unlike oil paint, the dried egg tempera film does not yellow or darken with age; however, it tends to be brittle.

Traditionally, egg tempera was made by mixing powdered pigments with a binder made of distilled water and egg emulsion. The egg emulsion was made with either egg whites, egg yolks, or whole eggs. Later recipes added drying oils and damar varnish to improve the handling properties and resistance to cracking. The disadvantage of using drying oils, like linseed oil, is that they cause yellowing. Due to the inherent lack of plasticity, rigid support is recommended where thick layers of paints are used. Once dry, the egg tempera paint film is water-resistant and has a matte finish. The matte finish can be polished with a silk pad to increase transparency and brilliancy or varnished to resemble an oil painting.

A prepared egg tempera emulsion cannot be stored for long even in a refrigerator. Simple egg tempera paint can be made by mixing watercolour paint, distilled water, and egg-yolk emulsion in equal proportions. A drop of vinegar can be added to stop it from going bad quickly but will cause brittleness of the paint film. An egg emulsion can no longer be used when it begins to decompose. Today, egg tempera paints are available commercially in tubes doing away with the fuss of preparation and concerns over shelf life.

Willow charcoal is made from branches. Vine charcoal is made from twigs of grapevines. The branches and twigs are burned in a kiln without any air to produce carbonised wood. Powdered charcoal is made by grinding carbonised wood.

Willow and Vine charcoals are light and brittle. They come in different thicknesses (thin, medium, thick, and extra-thick) and hardness (extra soft, soft, medium, and hard). The different types of charcoal produce a range of tonal values from light to dark. They are ideal for sketching and outlines before painting.

There are no binders used in the making of Willow and Vine charcoals; therefore, a fixative or retouch varnish is required to fasten the charcoal to the surface to prevent smudging or lifting. The downside is that the aerosol in the spray often darkens the charcoal.

Compressed charcoal is made by mixing powdered charcoal with a wax or gum binder and then moulding the mixture into sticks. Compressed charcoal comes in different hardness and grades (e.g., 2B, 4B, 6B) that are suitable for sketching and detailed drawings. The softer sticks make intense dark markings while the harder sticks make light marking. Charcoal pencil, which is compressed charcoal encased in wood, produces fine and crisp lines. Charcoal pencils are convenient and easy to use in detailed work.

Some manufacturers tint compressed charcoal sticks and pencils with pigments to produce muted and subtle colours. The term 'White charcoal' used to refer to compressed sticks and pencils is misleading because the product contains no charcoal; it's made of chalk.