Lightfastness of Artists' Pencils: Natural & Accelerated Exposure Results
SourceColored pencils are the medium of choice for many artists, however, there is currently no standard methodology to help artists choose between pencils with good, bad, or indifferent lightfastness. A research project to correlate the performance of artists' pencils was initiated by the ASTM D01.51.14 Colored Pencil Task Group. Three artist pencil manufacturers participated in the study. Replicate pencil specimens were exposed in Florida and Arizona benchmark locations under glass and in three different models of Xenon Arc lightfastness test apparatus. Two of the models were small, less expensive “tabletop” units, while the third xenon-arc was a full-size, free-standing tester. The resulting data was analyzed using both rank order and ASTM D4303 lightfastness categories. There was excellent rank order correlation between natural and accelerated exposures.