MITRA Forum Question Details

ApproveRejectUn-ApproveThanks. Sorry for the doubles on the color list.

ApproveRejectUn-ApproveThis is great question! The Verithin pencils are made with the same pigments as their counterparts in the Prismacolor Premier line: the only difference is in the type and amount of binder and fillers used, which make the Verithins harder than the sofa-core Premiers (so they are better at very fine detail work). Since the pigments are the same, though, you are, in general, safe in assuming that Prismacolor's lightfast ratings for the Premier pencils will be very similar for Verithin pencils that have the same color names. The lightfast tests that Prismacolor performs under ASTM standard D6901-15 are more rigorous than the tests CPSA performs under ASTM 5383-16, so using the information that Prismacolor provides on their webiste is an excellent choice. If you are concerned that the colors you want to use do not rate in the "excellent" or "very good" range, you can at least try to increase their longevity by working only on acid-free paper, framing with conservation-quality materials, using a UV-blocking final fixative, and framing with UV-blocking glass or plexiglass. Hope this helps! Deborah Maklowski, CPSA, CPX, Product Research Director, CPSA.

ApproveRejectUn-ApproveSorry I don't know if I was clear, I was asking about the col-erase line specifically. Would the colors in the col- erase line be using the same pigments as well? How does the erasable formulation affect lightfastness, if at all?

ApproveRejectUn-ApproveAlso, prismacolor does have lightfastness charts for soft core pencils and art stixs, and the verithins, and there are differences, for example a canary yellow has a 3 rating as a soft core pencil, and a 2 rating as a verithin. There are no lightfast charts for the Col-erase pencils. So just a bit confused.

ApproveRejectUn-ApproveMy apologies...for some reason I thought you were asking about the Verithins! Let me try again. First, yes, as you note, there will be some variances in LF ratings among pencils that use the same pigment amounts/ratios but combine them with different types/amounts of fillers and binders. That's why I noted only that the results could be "very similar": they won't all be the same. This will be especially true for very light colors, where the pigment load is not as high. (That's why watercolor pencils test better dry than wet.) As for the Col-Erase pencils: in order to make them erasable, they would need (at least) to reduce the amount of wax in the binder and use more "forgiving" pigments, both of which could adversely affect lightfastness. CPSA has never tested them, and, as you note, there's no test data on the Prismacolor site. However, that site does state that the Col-Erase pencils are best used for "illustration, animation, and accounting," which (to me) implies that they are not intended for fine art applications where longevity is desired. If you then compare the RGB and CMYK values for these pencils to those with similar names in other Prismacolor lines, it's clear that the formulations are very different. I don't feel, therefore, that the Premier LF results would be valid -- even as an assumption -- for the Col-Erase. But if you just work in generalities (which is all we have at the moment), we know that earth colors (the umbers, ochres, siennas. etc) are very stable colors, so I feel confident in saying you're probably safe using the black, brown, and terra cotta. Some reds and violets, however, can be fugitive, so in the absence of hard data, I think I would avoid the carmine, vermilion, scarlet, and tuscan red. That's all I have at the moment. I've sent off a request for LF ratings for the Col-Erase pencils to Prismacolor (but note that, given the pencils' suggested uses, it's possible Prismacolor has never tested them under ASTM D6901-16) and I've also sent out an email to some knowledgeable cp sources: if anyone sends me helpful information, I will post it here. And apologies again for the mix-up!

ApproveRejectUn-ApproveNo worries at all. Thanks so much.

ApproveRejectUn-ApproveI thought you would be interested in an update: I received a reply this morning from Prismacolor. They tell me that they have never tested the Col-Erase pencils for lightfastness, so that's why you couldn't find the ratings. CPSA will add them to our list of pencils to be tested. Thanks again for your question and for making lightfastness an important consideration in your art process.

ApproveRejectUn-ApproveThanks so much de