CPSA conducts ongoing lightfastness testing of its own using a sunlight exposure test in accordance with another ASTM standard – D5383. This testing was previously done by Rhonda Farfan, our Vice President of Consumer Standards Emeritus, and now carried on by our Product Research Director.
For each colored pencil to be tested, a small sample is made by heavily and evenly applying color to a test board. Half of each sample is covered to block out sunlight and the other half is left exposed. The samples are then placed in an outdoor box with a clear glass lid, made in accordance to ASTM specifications. The box faces south with the samples angled 45 degrees to maximize sun exposure on the uncovered portion of the test boards. Each board also includes a blue wool card with 8 different strips of dye with varying degrees of lightfasness. This card acts as the control and when it fades to a certain degree, we know the samples have been exposed long enough.
The next step is to place each pencil into one of the lightfastness categories (I, II, III, or IV, with I being the top rating). Five volunteers rate each sample on a scale of 1 to 7, and an average of those ratings is taken to determine the lightfastness category. These test results are made available only to CPSA members, Patrons, and Sponsors. An example of exposed samples and an exposed blue wool card appear below.
CPSA’s lightfastness testing represents our continued commitment to provide colored pencil artists with the knowledge and support necessary to make artwork that will last a lifetime!
|Color samples as rated by 5 independent observers, using the blue wool sample rating at right||Blue wool samples with lightfastness rating (with 7+ being the top rating, 0 being the worst.|