Q. For the last year, Ive been using a particular book as my guide for purchasing and using watercolor paints. The author advises against using paints that are considered fugitive colors, as well as those that havent received an acceptable lightfastness rating. With much angst, Ive given up some of my favorite colors, such as sap green, terre verte, alizarin crimson and rose madder genuine. However, I continue to see these colors recommended in magazine articles and recently published books. Could you give any insight on this issue?
A. The colors you listed may simply be the original names of fugitive colors that are now attached to a new colorant, or pigment, of more stable lightfastness. It could also be the original colorant in some cases&$151;but this depends on whos manufacturing or selling the paints.
For instance, sap green is no longer made from unripe buckthorn berries because the colorant was too fugitive; now a very stable, modern pigment is substituted for the original colorant. While the contents of the pigments have changed, the original color name is still in use. This is unfortunate, since it causes confusion in cases such as yours, but manufacturers are reluctant to let go of traditional color names for fear that artists will think a pigment is discontinued and stop using their product altogether.
You must decide whether you want to use a color you know is unstable, or find its stable equivalent. Sometimes its hard to determine whether the original pigment or a substitute is being used, but if the word hue appears after the color name, thats often a good indicator that the pigment is a substitute. Also, most reputable manufacturers now give the lightfastness rating of the colorants in the tubelook for the highest rating you can find. According to the American Society for Testing and Materials, the only acceptable ratings are Lightfastness I (a color that lasts more than 100 years under museum exposure) or Lightfastness II (a color that lasts close to 100 years under a museum exposure). A few companies still use their own rating system, so if youre interested in a particular brand of paint, look for the manufacturers site on the Internet: You may find useful information about lightfastness there.