St. Luke, painting the Madonna | 1515
Part of the Triptych of St. Luke and Egil
Niklaus Manuel
Here is some sound advice regarding best practices and materials for the oil painter. It comes from a FAQ made available by the Department of Conservation at the University of Delaware College of Arts & Sciences:
MATERIALS INFORMATION and TECHNICAL RESOURCES for ARTISTS – Myths, FAQs, and Common Misconceptions
1) Lead white, cadmium, copper, and chromium pigments should never be used because they are toxic...
Some metal pigments can pose a significant health risk particularly those that contain lead and other heavy metals. Lead white and other poisonous pigments are still considered essential for some artists, especially in oil paint where their unique handling, flexibility, and permanence have no adequate substitute. The dangers to the artist are primarily associated the pigment in its dry form where inhalation is a possibility. Pigments already ground into paint pose far fewer risks to the user. While most pigments are not readily transdermal, some solvents can facilitate absorption through the skin. These risks are completely mitigated by the use of gloves and proper hygiene. Dry pigments can be handled safely by using the proper precautions. Those working with dry pigments should only do so in a designated studio space and always wear a dust mask and nitrile gloves. Studios should be free of food and drink and the artist should make sure that they have completely removed any residual pigments or paint from their hands and clothing before leaving the studio. The area around the working space should also be covered with sheets of paper to catch any accidental spills. All materials contaminated with toxic pigments, including solid and solvent waste, should be properly disposed of. Please refer to the Health and Safety document for additional information.
2) Oil paints are toxic...
The binder in traditional oil paint is generally a drying oil derived from edible oils (flax, poppy, walnut, safflower, etc). On their own these do not pose any health risk (although there are a handful of individuals who may possess a particular allergy to certain oils). The toxic components in oil paints come completely from the pigments, additives like artificial driers , and solvents. Many commercial oil paint lines do incorporate vary small amounts of dissolved metal salts that are used to promote rapid or uniform drying. These driers often contain cobalt as well as other heavy metals and therefore care should be taken to avoid contact with the skin if these additives are present. By eliminating the use of solvents, many painters will find that they are able to paint using oils as long as proper precautions are exercised regarding driers and potentially toxic pigments. Please refer to the Health and Safety document for additional information.
3) Oils are bad because they yellow...
All drying oils will yellow to a certain extent but this process is a natural phenomenon and is not one associated with degradation. The yellowing of oil binders in a properly formulated oil paint is generally masked by thepigment load; however, adding too much oil to your paints can lead to pronounced yellowing, an effect that is particularly noticeable in lighter colors such as whites and blues. The manner in which an oil binder is prepared can also have an effect on the overall degree of yellowing as well as the presence of certain pigments (such as non-coated rutile titanium dioxide and anatase titanium dioxide), driers (oleates and resinates), and the environment (heat in the absence of light). There are measures that can be taken to combat yellowing. Some artists choose to place their paintings in direct sunlight for a certain period of time as UV light can break up some of the chemical bonds that are responsible for yellowing (although care should be taken if your painting contains a significant amount of wax and/or potentially fugitive pigments).
4) Alkyd mediums, polyurethanes, shellac, and hard resins (i.e. copals) are great as varnish coatings...
Today there is a wide-range of lacquer-, alkyd mediums- (e.g. Liquin), polyurethane-, and enamel-based coatings available to artists, some of which consistent of nitrocellulose (and other cellulose derivatives) or vinyl-based/acrylic resins dissolved in solvents. While many of these products dry fairly quickly, they are not recommended for use as surface coatings as they are irremovable once dry, can produce brittle surface coatings, and can potentially yellow and darken over time. These types of products have experienced a rise in popularity among contemporary artists and while they may create aesthetically pleasing surfaces for some, they have not yet been thoroughly tested for compatibility with art materials or for their long-term aging properties. Please refer to the Varnish document for more information on surface coatings.
The entire document may be found here:
Enjoy!
TJK
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