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Tuesday, September 16, 2008

Derwent Graphitint Colored Pencil Lightfastness Test

Graphitint pencils – graphite with color – seem like a perfect marriage of the wonderful qualities of working with graphite pencils with the excitement of color. Granted, the colors are muted and complex but those are some of my favorite colors.

Anyway, there I was all excited about them and then heard of a problem. In response to a comment from another artist who used the pencils in a journal where they had faded, I decide to perform my own, completely non scientific, lightfastness test.

The test was performed on a set of twelve Derwent Graphitint colored pencils. The color names in the set: Storm 18, Midnight Black 20, Chestnut 13, Port 01, Ivy 11, Aubergine 03, Coal Grey 23, Cloud Grey 22, Dark Indigo 04, Cool Brown 15, Slate Green 08, Cocoa 16. (Sorry they’re not in numerical order – it’s the order I put them on the sample card.)

I started August 17, 2008 by placing the sample, with the left side covered, in bright light from a south facing window but no direct sunlight. It was allowed to rest in the window for 14 days. During this time, there were a few more cloudy days than usual due to tropical storms in the area. I live in east central Florida where we have sunshine and bright light most every day of the year.

At the end of this first phase, there appeared to be no change in color of any sample. That’s a good start, but I then decided to subject the sample to direct sunlight for the same time period. While most people don’t display artwork in these conditions, it seemed an extreme test might be useful.

After 14 days of daily exposure to direct morning sunlight, there were two colors that had faded markedly – Chestnut 13 and Ivy 11 – and one that had faded somewhat – Cocoa 16. The two colors that faded the most lost all the apparent color and left only the graphite. The third color, Cocoa, faded some but the original brown color is still discernible. The other colors were unchanged to my eye.

In reviewing my results and the official lightfastness ratings from Derwent, I noticed significant differences in some of the colors. The colors that faded the most in my test are rated as lightfast and one of the colors that they rate quite low on the scale (Aubergine 03) did not fade at all in my test. Also, other colors (Dark Indigo 04 and Storm 18) are rated as not being fully lightfast by Derwent but they also did not fade in my test.

To conclude, I will say again that my method was completely unscientific though it gives me enough confidence to use the pencils in my own artwork. I will take some care with color choices and stay away from those that faded in my test. I’ll also use the ones with the lower Derwent ratings with care. If you are using these pencils and are concerned about fading, please conduct your own tests and review the manufacturer’s ratings for yourself before proceeding.

Now, it’s time to actually make some art!

3 comments:

Ann said...

Very interesting post! Thanks for sharing your results and words of caution.

quirkyartist said...

Thanks Monette. This is interesting. I got Graphitints last Christmas. I'm still battling they they have no real warm red, so I havne't used them a lot. I hadn't read about the lightfastness, so now I might limit them to my sketchbook.

Quilt Knit said...

No, this is exactly what the Scientist do to test lightfastness. They would have controls to show side by side. The control would be created at the sametime as the ones under the light. A Scientist would date each card and each card would have one color. Then the overall card with each color. All of these would be subjected to light. Indirect, direct, and indoor candescent and fluorescent lights. The controls would be placed in a completely darkened environment and left there till the end of the test for comparison.
I know-I was a Lab Tech, in the Paper world, and it included color studies.

Sherrie Roberts