Q. In 1965, several oil paint technologists warned artists against mixing alizarin crimson with any of the earth colors (the umbers, ochres, siennas and red oxides). They said the iron oxide in these earth pigments would react with and gradually decompose alizarin, and that 20-25 years later the alizarin would be completely black. Have any studies of alizarin-earth pigment mixtures (in oil) been made recently that would either prove or refute these claims? If their warnings were accurate, what would you recommend as the best overall alizarin substitute that can be mixed safely with traditional pigments?
Robert S. Johnson
A. From my research about paint and its constituents, I found only one caution concerning the mixture of alizarin crimson and earth pigments. This came from Paints, Painting and Restoration, a book written by Maxamillian Toch in 1931. Toch warns artists against these mixtures but he doesnt say why nor does he give any support for his warnings. While alizarin crimson isnt without its problems, it was introduced into the palette in the 1800s and many paintings from that time have their alizarin crimson glazes intact.
Prized for its bluish-red tint and its transparency, alizarin crimson is most commonly used as a jewel-like glaze and not mixed with any other color. The American Society for Testing and Materials has tested the lightfastness of many artists pigments, including alizarin crimson, and has developed a rating of I for excellent lightfastness, II for very good lightfastness, and III for fair. Alizarin crimson gets a rating of III. For this reason its recommended that you dont mix alizarin crimson with other colors, since using it full strength helps diminish the effect of any potential fading.
If youre looking for a substitute for alizarin crimson, some of the quinacridone reds have a similar bluish-red tone and a lightfastness rating of I in oil paints. Since quinacridone is quite a mouthful, many of these paints will have proprietary names, such as Acra red by Liquitex, that are considered more evocative of the color. Look for paints that list their actual pigment content (“quinacridone,” in this case) on the label, or, if its not listed, obtain it from the manufacturer. Then go ahead and experiment. As far as I can tell, substitutes for alizarin crimson can be mixed safely with other colors, though most people dont. There can be no true substitute of one pigment for another, but you may find one that will work for you and provide you with a more lightfast color.
Heather Galloway is a freelance conservator living in northern Ohio.