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QoR® Watercolor Questions: Labeling and Lightfastness Ratings

QoR Watercolor

Watercolorists are particularly sensitive to issues of lightfastness, and for good reason. Even when framed behind glass, watercolors are still vulnerable to fading because the pigments are very exposed to UV radiation and often used in dilute and delicate washes. Since launching QoR we have received many questions on why some of our colors have a Lighfastness rating of NA, meaning Not Applicable, even while the large majority have an ASTM Lightfastenss of I and just a handful have a II. There have also been questions on why other companies might show a Lightfastness or Permanency rating for an identical pigment that we mark as NA. We wanted to be able to address these concerns directly with you.

The American Society for Testing and Materials (ASTM) creates technical standards that are followed worldwide in all industries and their “Standard Test Methods for Lightfastness of Colorants Used in Artists’ Materials” (D 4303) is by far the most widely accepted and scientifically backed testing procedure currently in place for evaluating how durable a pigment might be. Because of this, we feel strongly that companies should adhere to this standard whenever reporting the lightfastness of their materials.

ASTM Standards for oil, acrylic, and watercolor each maintains a completely separate list of pigments rated for that specific medium. So a pigment listed for oils or acrylics will not necessarily appear on the one for watercolors, and vice versa. Furthermore, the only way to add a color to a list is to put it through all the testing specified by ASTM, including both prolonged outdoor and accelerated indoor exposures. Once completed, those results are submitted to the committee and if approved the color can be included on the list and its ASTM rating placed on a label. From start to finish this process usually takes several years, and sadly no watercolor manufacturer we are aware of has stepped forward to update and expand that list in recent memory. As a result, many pigments with long histories in oils and acrylics are still not included and until that changes, we must list them as unrated when used in watercolors. That is the short term situation. Longer term, we have started a very large project to have all of the colors that we list as NA go through the necessary ASTM testing and be submitted to the committee for approval in early 2016. Once that work is completed we will finally be able to revise our color charts and labels to reflect those official ASTM ratings.

QoR Labels

Shown above are lightfastness ratings as they currently appear on product packaging.

We also want to comment on the use of either a separate “permanency” or lightfastness rating not backed by ASTM. While companies will sometimes use these to supplement or even substitute for an accepted ASTM rating, it is important to realize that only ASTM Standards are peer reviewed by a broad group of manufacturers, scientists, and other consultants and experts in the field, and only approved and published after substantial testing can confirm that the results are reliable and repeatable. Because of that, these private, alternative ratings can mean so many things that without knowing the specific tests that were done, and the exact procedures followed, it is hard to say how accurate they are. As tempting as it is to go that route, we feel that working through the more rigorous ASTM methods is a better solution and provides the assurance that the ratings are backed by a scientifically accepted standard that is available to anyone to read and verify.

We hope this helps explain why some of our QoR paints currently have no lightfastness rating. As always, if you have any concerns or questions about the lightfastness of any of our colors, contact us at 607-847-6154 / 800-959-6543 or email help@goldenpaints.com.

4 Responses to QoR® Watercolor Questions: Labeling and Lightfastness Ratings

  1. Steve Gruber August 10, 2016 at 7:30 pm #

    I enjoyed your open and honest posts. I will print them all and look forward to future ones. Just began using QOR watercolors and love them. They do handle differently; it seems that I can push the color around longer and the lifting is great even with staining colors. My tests show as good, or exceeding Winsor and Newton, in vibrancy. Thank you, Steve Gruber, California

    • Sarah Sands August 30, 2016 at 3:30 pm #

      Hi Steve –

      Thank you SO much for the warm words about our articles! That means a lot to us. And its also wonderful to know that we are holding up in all of your comparative testing. While we can talk all day long about what we put into the paints, hearing from artists directly about how we are meeting or exceeding expectations is especially gratifying. As always, if we can help further, just let us know!

      Sarah

  2. Loretta November 13, 2016 at 7:14 pm #

    Hi, I am learning watercolor painting. I love this medium. I bought two sets of Qor watercolor tubes as my professional watercolors. I love them they are beautiful.
    i needed to refill my reds in my pallette. My two reds are pyrrol and pyrrol red light. When I opened my tubes again I have no red. The paint looks black. I squezzed some out and mixed with water and they are black/blue. Wierdest thing ever. I s this what they mean by fugitive color? Thank You Loretta Gentle

    • Sarah Sands November 21, 2016 at 10:27 am #

      Hi Loretta – Thank you for the comment and letting us know. Fugitive definitely does not mean that a color should come out of their tube looking black! How very strange. The only thing we can think of is the possibility that the area near the neck of the tubes got contaminated with other colors. Do you think that is a possibility? In other words, that perhaps in squeezing out some color you accidently picked up some black or else something like a Phthalo Green or Blue, from the palette? If not, then we would definitely love to get the tubes back and send you out replacements as obviously Pyrrole Red should be, well, red! If you can, let us know your thoughts and if possible send us your address and even better, a picture of the tubes and the black color that you see when squeezing them. You can mail those to us at help@goldenpaints.com

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