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JamieWG
12-12-2019, 04:09 PM
Yellows:
http://www.wetcanvas.com/Community/images/12-Dec-2019/13766-0A03211B-3154-497B-B514-51E4EC3EAC17_1_105_c.jpeg

I've had some pastel lightfastness tests brewing in my studio window for five years, and finally got around to posting the first installment of the results. This first post covers the full 48 stick set of Charvin Water Soluble pastels, which are supposed to be lightfast and pure pigment. As you can see from this example, things aren't always as claimed. You can see the full post with all the colors and my summary here on the Hudson Valley Sketches blog (https://hudsonvalleysketches.blogspot.com/2019/12/lightfastness-tests-charvin-water.html).

If enough people find it useful, I'll post the results of the other brands I tested over the next few weeks, as I have time to photograph and write about them. It took most of my morning to get these photographed, adjusted, and written up, and maybe I'm the only one who cares about lightfastness! LOL So, I'm trying to gauge interest before I take the time to post the other brands I tested on the blog.

This is the set I'm discussing in the post:
http://www.wetcanvas.com/Community/images/12-Dec-2019/13766-A096D016-0F4A-4A9F-A843-59C0783F9287_1_105_c.jpeg

Thank you in advance for letting me know if this is of interest to you, and supporting the idea of lightfastness testing for ALL of our art materials!

water girl
12-12-2019, 04:16 PM
Thank you for posting. Are all your colorfast samples exposed for 5 years? I am not familiar with particular brand. I would be interested in NuPastel.

JamieWG
12-12-2019, 04:31 PM
Thank you for posting. Are all your colorfast samples exposed for 5 years? I am not familiar with particular brand. I would be interested in NuPastel.

Yes, all the samples were exposed for five years in my south facing studio window, in the northeastern US. (So, not a whole ton of light, even facing south.) They also were not angled to directly face the sun, but rather leaned against the window.

I didn't test NuPastels because they don't even claim to be lightfast, so I didn't much see the point. However, I have the full Nupastel set, so maybe I will start a test of those at some point.

My Beloved Muse
12-13-2019, 12:53 PM
Thank you for this work. And, yes, Id be very happy to see more.

John

JamieWG
12-13-2019, 05:22 PM
Thank you for this work. And, yes, Id be very happy to see more.

John

Thank you for letting me know, John. I had some friends painting with me in the studio today, and was discussing with them how difficult it is to decide if all that work to make the info public is just a waste of my time. I appreciate your feedback.
Jamie

DBfarmgirl
12-14-2019, 03:37 PM
I would also be very interested.

I left a couple mungyo pastels on the window sill, a couple yellows, orange, etc not pink or purple (which I would assume would fade). Within a couple months the exposed side had faded considerably. Glad I only bought a couple.

I think with all of the new red, pink, purple pigments that are lightfast there really isn't an excuse for professional materials to fade.

Back a couple hundred years ago, when I was an art student doing watercolor, cool reds, purples always faded, alizarian crimson, rose madder, some napthol. Everything changed with the quinacrodone pigments. The discontinued winsor newton pastels had many colors that used the quin pigments, I am happy to have a few as I trust them to fade less.
Sharen

DAK723
12-14-2019, 07:36 PM
While lightfast testing can be informative, I would caution everyone about putting too much stock in lightfastness testing results. An article about the testing linked here:

https://www.justpaint.org/delta-e/

Gets pretty technical, but the one important bit of info that I would like to pass along is that even the pigments with the highest rating (ASTM I) might fade about 25% of their original strength and even a middle lightfast rating of ASTM II might fade approx. 50%. But before everyone starts panicking, I think the most important aspect of lightfastness can be summed up by another quote from Sarah Sands that has been posted in the oil forum that says:

I also would want to caution against something that is not well understood by most namely that accelerated lightfastness results are not meant to be predictive. That can be frustrating for many artists because of course that is exactly what they are hoping to know will this or that color fade in this or that way after, say, 100 years. But that degree of certainty just does not exist in these types of tests for a range of complex reasons.

In other words, putting a painting in direct sunlight to accelerate the testing does not make it possible to predict what will happen to the same pigments when NOT exposed to direct light.

I make sure to never hang paintings in a spot where direct light hits -or at least a spot where it almost never happens. When attempting to sell a painting, I would always put a note on caring for the painting - and saying "Do not hang the painting where it receives direct sunlight" would be one of those instructions.

Don

JamieWG
12-16-2019, 12:28 PM
While lightfast testing can be informative, I would caution everyone about putting too much stock in lightfastness testing results. An article about the testing linked here:

https://www.justpaint.org/delta-e/

Gets pretty technical, but the one important bit of info that I would like to pass along is that even the pigments with the highest rating (ASTM I) might fade about 25% of their original strength and even a middle lightfast rating of ASTM II might fade approx. 50%. But before everyone starts panicking, I think the most important aspect of lightfastness can be summed up by another quote from Sarah Sands that has been posted in the oil forum that says:
In other words, putting a painting in direct sunlight to accelerate the testing does not make it possible to predict what will happen to the same pigments when NOT exposed to direct light. I make sure to never hang paintings in a spot where direct light hits -or at least a spot where it almost never happens. When attempting to sell a painting, I would always put a note on caring for the painting - and saying "Do not hang the painting where it receives direct sunlight" would be one of those instructions.

Don

Don, I agree with everything you say. However, please note:

These are NOT accelerated test results with artificially-induced light.
The light was always filtered through at least 2 panes of glass, and sometimes three. Light is shielded during part of the day by shrubbery on either side, so probably not more than a few hours a day of light, which isn't all that strong in the northeast anyway. The strips were slightly angled down, rather than directly facing the light. So, "direct light" is relative.
Five years is a very short time , and I agree that five years in indirect light might not change these pigments at all. But I think my tests are at the very least an indicator that these particular pigments are more susceptible to change than the others that didn't change. Which brings me to the fact that..
28 of the sticks did not change at all. While those too might change over a long period of time, I'd conclude that they stand a better chance of survival than the ones that faded or changed so quickly. Unfortunately, none of us can test indirect lighting for 200 years. :wink2:
Lastly, my tests are not scientific, nor done even close to the same standards as Golden. (Which I have visited many times!) They were done under my own conditions, for my own knowledge and benefit, and to draw my own conclusions. Everybody else's mileage may vary, and their journeys and destinations may be different than my own. That's a good thing! I always encourage others to do their own testing, mimic whatever conditions they wish, and judge for themselves. That's why I did these tests.

For many people, and for many different reasons, lightfastness doesn't matter. That's fine too. I'd rather know and not care, than care and not know! When I work in my sketchbooks, I really don't care. I even use fountain pen ink there, and if you want to see something disappear in sunlight before you can even say, "Hokus pokus," try fountain pen inks! LOL ;)

Tracy2000
12-30-2019, 03:11 AM
Interesting results Jamie!

Of course, those Charvins could be pure pigment....it's just that the pigment used may be fugitive (not lightfast). I'm coming to pastels from watercolor and one of the things that was initially SUPER frustrating about soft pastels was the lack of information on pigments used. (now it's only.... moderately?...frustrating). No professional-level watercolor lines can escape sharing pigment information and there are many pigments that historically (until quite recently) were very popular that are now known to be fugitive.

I wish that pastels were labeled with the pigments used (the way watercolors are) because it would sure be a lot easier to make some buying decisions with an eye to lightfastness! I really wanted to know pigment info when starting with pastels too because my grand plan was to buy pastel colors that matched the pigments/colors in my watercolor palette (i.e., get the pure pigment, then tints and shades).

Sigh.

LOL.

JamieWG
12-30-2019, 05:48 PM
Interesting results Jamie!

Of course, those Charvins could be pure pigment....it's just that the pigment used may be fugitive (not lightfast).

Right, Tracy. Many of the pigments are not lightfast. However, the packaging says "lightfast" right on the cover!

I'm coming to pastels from watercolor and one of the things that was initially SUPER frustrating about soft pastels was the lack of information on pigments used. (now it's only.... moderately?...frustrating). No professional-level watercolor lines can escape sharing pigment information and there are many pigments that historically (until quite recently) were very popular that are now known to be fugitive.

Tracy, I am so with you on this! I have no idea how the pastel companies have gotten away with it for so much longer than other media. I paint in oil, acrylic, watercolor and gouache. I always choose my pigments carefully for these media! I've tested the Polychromos pastels and many Mt. Visions, and the Conte Pastel Pencils, and will be publishing those results on my site over the next few weeks. (Taking a holiday break from blogging!) It should really be the pastel companies doing this, not us! ;)

Tracy2000
12-30-2019, 10:31 PM
Jamie, I'll be extra interested in the results of your Mount Vision tests since that is the main brand I've been collecting!

contumacious
01-13-2020, 01:20 PM
In other words, putting a painting in direct sunlight to accelerate the testing does not make it possible to predict what will happen to the same pigments when NOT exposed to direct light.

Don

The point Don is making - you must not allow ANY direct sunlight to fall on your test swatches to get realistic fade testing. Direct sun will fade almost all pigments. Unless I am reading the OP's comments incorrectly there was direct sunlight falling on them at least part of the time for 5 years. Maybe try the same test but make sure no direct sun ever touches your samples and compare them in 5 years to your current set.

JamieWG
01-15-2020, 09:06 PM
The point Don is making - you must not allow ANY direct sunlight to fall on your test swatches to get realistic fade testing. Direct sun will fade almost all pigments. Unless I am reading the OP's comments incorrectly there was direct sunlight falling on them at least part of the time for 5 years. Maybe try the same test but make sure no direct sun ever touches your samples and compare them in 5 years to your current set.

Many of the samples did not fade at all in five years, so clearly some pigments are more light resistant than others. Thats the point Im making. Those too might start fading over time, but in terms of longevity, by my tests, their lightfastness is better. I wont be around for 200 years to do an adequate indirect light test!