I had the wonderful opportunity to attend the IAPS meeting in Albuquerque, NM, last week and delivered a lecture on lightfastness testing of pastels. The audience was fantastic! Lots of great questions were posed on the issues involved. I believe that pastel artists have become accustomed to the notion that some pastels fade when exposed to light. My presentation on lightfastness problems concerned the audience but did not shock them as it did when presented several years ago by one of my colleagues.

The key to getting manufacturers to create reliable pastels will come when the American Society of Testing and Materials (ASTM) establishes a pastel standard. This standard will map out the protocol for conducting lightfastness testing, enabling manufacturers to test and evaluate pastels they make so if several color mixtures don't meet adequate lightfastness ratings, they can reformulate the pastels.

That standard is a year or two away from completion—if no serious impediments come in the way of the current writing and preliminary testing process. The one refreshing aspect to this pastel standard will be that finished pastel products, not just the pigments themselves will be evaluated. This is important because some pigments can perform well without any additives, but when mixed with other components, the combination of materials will result in an unstable product in terms of lightfastness. The opposite can be true as well. Unstable pigments may perform well when mixed with other pastel ingredients and prove to be highly lightfast.

Pastel artists don't have to be held captive when it comes to knowing what colors are good performers and those that fade fairly quickly when exposed to light. A protocol that provides a very good indicator of how materials will behave if exposed to light, is available for anyone to use. The method is fairly simple. Artists can prepare a suitable sample card that exposes a portion of the pastel to light while leaving a portion masked from any exposure. For a how-to on testing your own pastels for lightfastness, click here.

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