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ARTISTS'COLOURS Some health, safety and environmental aspects A statement by C.E.P.E (The European confederation of Paints, Printing Inks and Artists'colours Manufacturers'Associations)
With
colours the artist creates objects of lasting value. Justified concern sometimes creates prejudice. This information paper is intended to openly discuss the situation for the benefit of art and the artist.
The pigment determines the visual characteristics of the colour, its hue and transparency. Pigments are finely ground, coloured powders, which may be natural or synthetic, they may be further classified as inorganic, those of mineral origin, or organic, derived from carbon compounds. The binder acts as an adhesive ensuring that the pigment is securely attached to the painting ground. It also affects gloss, transparency, and gives the particular medium its characteristic properties. Quality artists’ colour cannot be produced by simply mixing pigment and binder, additives are necessary to give stability, flow and drying characteristics. The optimum use of all these components is part of the art of the colour manufacturer. In this age of concern for our environment it is important that the artist is aware of the nature of the materials being used, but it is equally important that those materials meet the quality and permanence required.
Nowadays artists’ colours are manufactured wherever possible using pigments which do not present a health-hazard to the user. That was not always the case, however. The “orpiment”, highly regarded in the Middle Ages and the ancient world for yellow colours, was highly poisonous owing to its arsenic content. Similarly toxic were the historical pigments realgar, red lead (minium), verdigris and Schweinfurter Green. People found many of these toxic pigments in nature or produced them from natural ores. The “natural” origin of these colours is therefore no measure of their non-toxicity. The brilliant tones of the historically toxic colours are today replaced by colour manufacturers with harmless, synthetic pigments. Some inorganic pigments now contained in artists’ colours do, however, contain heavy metals. Unfortunately, the term “heavy metals” is often equated automatically with “toxic”. Many heavy metals contained in artists’ pigments such as iron, manganese, and zinc, are, however, essential trace elements but may have a detrimental effect in higher doses. Some heavy metals, found in artists’ pigments, do require further explanations, though, as they can be harmful. Even the more harmful pigments can be used safely if the necessary precautions are taken, such as good ventilation of the room, avoiding oral intake of colours/paint, avoiding inhalation when using a spray-gun/airbrush.
White
lead (Flake White, Kremnitz or Cremnitz White) is probably the only
really harmful pigment, but the use is not very wide-spread anymore.
Barium
may be found in lake pigments and toners. Barium sulphate is often
used by pigment manufacturers to adjust batch strength but as is
insoluble, it does not constitute a danger in normal use. Cadmium pigments Cadmium
pigments occur as cadmium zinc sulphide (yellows) and cadmium sulphoselenide
(reds). Soluble cadmium compounds are toxic but the method by which
modern cadmium pigments are manufactured makes them virtually insoluble
and therefore not a danger in normal use as an artists’ colour. Chromium pigments The
artist may encounter chromium as Oxide of chromium or Viridian an
as Lead Chrome Yellows. Lead, Barium and Zinc chromates are dangerous
to health, but most manufacturers have stopped using them. The chemical
nature of the chromium in the two greens is such as to render the
chromium different to that in the lead chromate pigments, and is
not a hazard. Cobalt Cobalt
will be encountered by the artist in drying mediums and as Cobalt
Blue, Cobalt Green, Cobalt Violet and Cobalt Yellow (Aureolin).
In the dry powder form as pigment, these can cause respiratory allergies
if inhaled. Ingestion hazards depend on solubility. Cobalt Violet
and Cobalt Yellow will be the most harmful as they have greater
solubility. There is no danger from normal use. Copper Many
historical pigments contained copper in a soluble form which would
be harmful if ingested, such pigments have long since ceased to
be used. Copper is present in phtalocyanines, but is complexed in
such a way as to be virtually unavailable for absorption into the
body. Mercury Mercury is found in the pigment Vermillion, but mercuric sulphide is virtually insoluble and only if soluble impurities are present does it constitute a danger.
IN GENERAL A pigment has to be taken into the body for it to present a health hazard. It then has to be soluble in the stomach acids and be absorbed into the body to be harmful. Some pigments might cause health problems if absorbed into the lungs over a prolonged period of time.
The binders for oil colours are natural vegetable oils (linseed, sunflower, safflower, soya, poppy) and sometimes natural resins (dammar, mastic) and synthetic resins (cyclohexanone, alkyds). Normal contact with these materials does not constitute a health hazard. Metal driers, e.g. cobalt and manganese, may be used in small quantities to improve drying but at these levels they do not represent a hazard. The binders for water colour and gouache also come from natural sources, gum Arabic, dextrin, gum tragacanth and cellulose derivatives. The emulsions used acrylic colours are suspensions of resin particles in water, they do not constitute a health risk in normal use. The
solvents used by artists are of more concern. These are volatile
materials which could be inhaled when in use. Turpentine which is
distilled from natural extracts of pine can cause allergic reactions
and irritate the skin and respiratory tracts. White spirit is perhaps
less hazardous but grades can vary. When using such solvents ensure
adequate ventilation and avoid breathing the vapour. Do artists’ colours harm our environment? Pigment containing heavy metals, particularly lead and cadmium, should not be allowed to pollute the environment. Cadmium pigments, although not biodegradable, will give off toxic gases if incinerated and may adversely affect sewage treatment. Unfortunately there are no substitutes with the characteristics of cadmium pigments. Artists’ should use and dispose of them responsibility. The binders used are for the most part natural gums, oils, and resins, hence renewable raw materials. Their use can cause little harm to the environment. The synthetic resins such as acrylics, should be disposed of carefully, preferably as dried material. Artists’ use of these materials is minute compared to industry in general. Neither the natural nor the synthetic binding agents contaminate household refuse especially. There are no chlorinated hydrocarbons used only halogen-free hydrocarbons. These can be either incinerated or dumped. The quantity uses, moreover, is small. Solvents do require consideration in relation to the environment. Solvents both natural and synthetic, can contribute to the “greenhouse effect”. Halogenated hydrocarbons, and CFC’s formerly common in aerosols, which can pose a threat to the ozone layer, are no longer used. All artists’ material manufacturers operate within the limits required by strict EU rules for discharge of waste and by-products into the environment.
These will be subjective, according to the artists’ individual attitude. Some will attach importance to the colour brightness, other to permanence. It is not always possible to realise all the desirable properties simultaneously. It is important to the artist for an artists’ colour to indicate clearly on the label what pigment it contains. It is important for the artist to know whether he or she is using genuine cadmium or a substitute. The character of individual colours should not vary over time within a branded range of good quality products. Carefully controlled additives ensure this consistency. Artists’ colours containing “only pigment and binder” will not achieve this. The permanence, durability and light-fastness of artists’ colours are important for the completed work of art, and good quality colours will have statements regarding composition and permanence on the label. Such labelling will meet international legislation and artists should pay special attention to any warnings given on the label. Artists’ materials are generally safe if used in the manner in which they are intended and care is taken by the artist not to dispose of material carelessly. A number of ingredients used in artists'colours are classified as "being toxic to aquatic organisms". Products which do contain these ingredients are labelled accordingly.
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