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

12 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!


  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

  3. Lindsey Waters February 11, 2017 at 6:35 pm #

    Thank you guys for the info! I am the manager of the art department at a Guiry’s in Littleton, CO and this information is so helpful! I love selling and using your paints and articles like these make it so simple! Thanks guys!

    • Sarah Sands February 11, 2017 at 6:55 pm #

      Hi Lindsey –

      You are so welcome!! It is SO great to hear that the information is helpful and that it makes your job of supporting our products easier – feedback like that means the world to us. And if there is anything else we can ever do – or if there are types of articles you would ever like to see – just let us know!

  4. Mark Strodl August 10, 2017 at 8:12 am #

    Excellent Info, this permanence is still scaring the hell out of me Sarah. In Digital we talk of Archival all the time. Yet here, impermanence seams to be the game of the day. 5 years ??? OMG

    • Sarah Sands August 10, 2017 at 2:03 pm #

      Hi Mark –

      Not sure what the 5 years is in reference to (let us know!) but we agree that lightfastness is a much needed area of research and testing and it can be scary when confronted with so much differing information. We promise that we will always share in a transparent way the testing we have done and know that if we ever discover that something is not as lightfast as we – or our customers – would expect, that we will take measures to address that and let people know. As we did, for example, with Hansa Yellow Medium:}

      Hope that helps!

  5. Claudia January 12, 2020 at 3:43 pm #

    What does GD and EX mean on the lightfast label of some colors?

    • Cathy Jennings January 29, 2020 at 11:42 am #

      Hello Claudia,
      When a pigment we use in QoR is not rated for lightfastness by ASTM, or our own internal testing of that pigment’s lightfastness shows it has better lightfastness than the ASTM rating, we use “EX” and “GD”. “EX” stands for “Excellent” and is equivalent to ASTM Lightfastness I. “GD” stands for “Good” and is equivalent to ASTM Lightfastness II, or “Very Good.”
      Warm Regards,


  1. Doodlewash® ~ DOODLEWASH REVIEW: QoR Watercolors - January 16, 2018

    […] set pops up along with properties and labeling info.  Labeling and lightfast ratings article here.   QoR Colors Pigment Chart pdf here.  Their site is very nice, interactive and user friendly- […]

  2. The QoR mini Half Pan Travel Set and Color Mixing | Just Paint - December 11, 2018

    […] Eight of the QoR mini paints contain pigments rated lightfast I or II by ASTM. We determined lightfastness ratings of the other four paints by following ASTM’s protocol for testing. The pigments in Pyrrole Red Medium (PR254) and Transparent Pyrrole Orange (PO71) do not currently have ASTM ratings, and our testing showed them to be LF I (Excellent) and LF II (Very Good), respectively. The pigments in Quinacridone Magenta (PR122) and Dioxazine Purple (PV23) already have less than ideal ASTM lightfastness ratings, so we tested our QoR paints containing these pigments as well. We found that both of these QoR paints showed excellent lightfastness, equivalent to ASTM LF I. Because of the discrepancy between our ratings and ASTM’s ratings, these paints are listed as Lightfastness NA. More information may be found in the Just Paint article “QoR Lightfastness Testing Update.” […]

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