Scientific Research

The Application of X-Ray Powder Diffraction to the Analysis of Synthetic Organic Pigments. Part 2: Artists’ Paints

Have you heard? We recently became aware of a recent study of 50 types of artists paint by the research department at the National Gallery of Art. These paints, including C.A.S. AlkydPro, were tested to identify pure pigments. All of our AlkydPro pigments were easily identified in the tested samples! Not so with Griffin Alkyds, the pigment contents of Griffin were difficult to identify and also all the” professional oil paints” as there were so many fillers! Unbiased scientific proof that C.A.S. AlkydPro paints contains maximum pigment concentrations, and no fillers or adulterants. The combination” of a non-yellowing alkyd resin and high quality pigments makes our colors lightfast and pure. Tubes of AlkydPro go further due to high pigment load and high tinting strength.

Online Abstract: Over 50 commercial paints were examined by x-ray powder diffraction in order to try and identify the synthetic organic pigments present. The binders included acrylic, oil, gum, and alkyd. Some pigments could be identified, though analysis is often complicated by the presence of large amounts of fillers and extenders in the paints relative to the small quantities of the pigment. A few of the paints did not have reflections due to fillers or extenders but the pigments could still not be identified. The best success in identifying the pigments was with acrylic binders, where the pigments could be identified in more than half of the samples examined, and with alkyds, where the pigment could frequently be identified. However, other binders,especially oil and gum, contain so many fillers that the pigment reflections are obscured. X-ray powder diffraction, therefore, is of limited utility in the identification of synthetic organic pigments in paints.

A brief selection of text:

“The CAS alkyd paints were all single pigment materials. All of the CAS alkyd paints produced powder diffraction patterns containing the expected pigments. However, this is not the case with the Winsor and Newton Griffin Alkyds.”

The Application of X-Ray Powder Diffraction to the Analysis of Synthetic Organic Pigments. Part 2: Artists’ Paintts.

by Suzanne Quillen Lomax, Scientific Research Department, National Gallery of Art. This quote, excerpted from the above paper in Journal of Coatings Technology and Research is not an endorsement of a specific product on behalf of either the author or the National Gallery of Art.