What is Lightfast and What is Lightfast Testing for Colored Pencils?

Nov 19, 2022
Colored pencil Swatches FREE Layering and blending with colored pencils

Hello Fellow Artists!

In one of my Live Zoom Draw-Along's, the subject of lightfastness came up.

Hopefully, my blog will clear up any questions!

First, can I just tell you about my experience with fading artwork! Uggg!

About seven years ago, when I started painting and drawing again, I knew that the sun was not good for artwork. Common sense, right? 

I heard about lightfast testing, but I never really paid attention, thinking that all my artwork was displayed inside, so I didn't need to worry about it. (total rookie move) 🐸

Then, it happened. One of my drawings faded during an exhibit. Oh man, was I embarrassed. 

It was my first local exhibit, and I was so excited that my art was accepted. And it got even better; my art was one of the first pieces you saw when you walked into the door! I was so honored! 

There was a con to having my art displayed by the front door with many windows, it was in the daylight for weeks, and the colors of my artwork faded.

Not just a little where only I could notice, it faded a lot. 

I was inspired to do research. Figuring out what is a lightfast test and who tests the pigments? 

First things first, what is the actual meaning of Lightfast? 

According to one organization that does standardized tests;

"The artwork will last in excess of 100 years in gallery conditions."

So, there are two standardized lightfast tests in the colored pencil industry. 

The ASTM scale and the ISO Blue Wool Scale. 

✍️ ASTM (American Society for Testing Materials) standard D6901 uses an I-V scale; I and II being lightfast.

✍️ The ISO (International Organization for Standardization)105 Blue Wool scale is 1-8; with 6 or more being lightfast. 

It's a little confusing with Faber Castell's Polychromos; they use the Blue Wool scale, but instead of numbers, they use stars to reflect the Blue Wool scale results. So they have a scale for the scale. 🀯

 *** = Maximum lightfastness = 7 ,8 Blue Wool Scale

Maximum fade resistance (100 + years)

** = High lightfastness = 5, 6 Blue Wool Scale

Very good fade resistance

* = Reasonable lightfastness = 3, 4 Blue Wool Scale

Good fade resistance

So, I made swatches of all 120 Polychcomos pencils, and I put each pencil's stars next to the color; much easier for me to read than the tiny star on the pencil! Most of them have three stars. 

You can download the chart here if you'd like to use it. Polychromos Color Chart

Tip: I would suggest printing them on thicker stock paper than regular printer paper:

Caran d'Ache Lumeninece Uses the ASTM D6901 The newer Luminance pencils are much easier to read and have the lightfast rating I or II on the pencil. Most of them are I. 

Here is the color chart with the lightfast numbers for all 100 Luminance pencils: 


Derwent Lightfast uses the ISO 105 Blue Wool test, which was originally developed for the textile industry. A scale of 1-8 is obtained, with values of 6 or more being considered GOOD and will last in excess of 100 years in gallery conditions.

Here is the color swatch that I made of all Derwent Lightfast pencils. 

Download it here: Derwent Lightfast Pencil Chart

During my research, I discovered the Colored Pencil Society of America. The non-profit organization was founded on and takes pride in conducting its own ongoing lightfastness testing using a sunlight exposure test in accordance with ASTM standard D5383. 

I'm now president of the CPSA's Chicago chapter; it's so funny what roads life takes you down! 

Here's what is on CPSA's website about lightfast numbers I-V

"Lightfastness categories are I, II, III, IV, and V with I being the best (very lightfast) and V being the worst (fugitive/not lightfast). Only pencils with lightfastness ratings of either I or II can be labeled as complying with the standard. For an entire line of colored pencils to be labeled as D6901 compliant, every pencil must have a lightfast rating of either I or II."

Here is a sneak peek of a display that was up during the CPSA International Show and Exhibit. I had the pleasure of sitting next to the person who does all the lightfast testing for all the different pencils.  

You can see that there is a lot of fading with some pencil pigments! You have to be a member of CPSA to get the latest book with all the testing results. :-) All links are below

The Take-Away 

If you plan to sell your artwork, display it for an exhibit or show, or give it as a gift, I recommend using lightfast-tested colors only for your artwork.

If you liked this article and would like more, please subscribe to my blog! 🎨 ✍️

Also, my Colored Pencil Nerds Membership will be open for enrollment again soon! Sign up here to be notified!

Thank you for reading, fellow artist, and I hope to see you soon in the membership! πŸ™ 🎨

Molly 🌻

Molly's Fine Art Academy

Here is the link to CPSA website about lightfast testing: cpsa.org/about/testing-by-cpsa/

Here is the link to the ASTM standards website: www.astm.org/d6901-15r21.html

Here is the link to the ISO Blue Wool Scale standards website:


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