Friday, April 16, 2010

Lightfastness and Dyes

Dyes differ from pigments because they dissolve easily in the vehicle or they are liquids themselves. They are used in markers because their solubility helps them disperse through the felt tip by means of capillary action.

Many dyes are susceptible to fading, but it all depends on the particular colorant, and in the older packaging, they don't tell you the colorant.

In this test strip made from a few older (early '80s) bottles of Dr. Martin's dyes, the violet color completely vanished.

The molecules in older synthetic aniline dyes were especially fugitive, or susceptible to fading.

However, recent technological advances have improved Dr. Martin's and other brands of dyes. They generally now use micronized pigments rather than the more vulnerable synthetic anilines.

Many of these same improved dyes are used in staining leather or wood, and they're much better than they used to be.


Joe Jusko said...

I used a lot of mixed media when I first started over 30 years ago, Dr. Martin's being part of my mix. I've had to repair/retouch almost all of the early originals due to the dyes fading out. I feel so guilty when I see an original I sold so many years ago turn up in someone's collection in horrible shape that I always contact the owner with an offer to restore the piece in a more permanent medium such as acrylics.

tiffannysketchbook said...

thanks for this information.

This is the reason I'm hesitant to use gouaches, I heard they are highly fugitive as well. :(

Dan Gurney said...

I wonder about the environmental and toxicity dimensions of the quest for lightfast dyes and pigments. I would guess that as compounds are made to be more lightfast that they tend also to be harder on the environment.

bill said...

I'm with Mr. Jusko. Back then Dr. Martin's were an illustrators friend. The brilliance was so seductive and who worried about longevity with illustration. Since then originals have become more important for me than the illustration. I even search out archival inks to use in my sketchbooks. I often use ballpoint so am always on the lookout for a good, archival, lightfast ballpoint pen. And Mr. Dan Gurney, do you have info about environmental effects? I would really be interested.

Don Cox said...

" I would guess that as compounds are made to be more lightfast that they tend also to be harder on the environment."

I would expect the opposite. The most lightfast pigments around are the iron oxides, which are harmless to the environment.

A pigment or dye that fades is one that easily changes chemically. That would make it more likely to be toxic.

An insoluble pigment will have less effect on the environment than a soluble dye.

But in any case the amount of paint or ink used for pictures is so small compared to the amount used for painting houses or industrial plant, or printing magazines, that its effects must be negligible.

Dan Gurney said...

Hi, Bill. I have no information at all. I would guess my brother James knows quite a bit on the subject as would some readers of his blog, like Don Cox who comments just above me here. Like you, I'm simply interested. And I'm pleased to know that my concerns might be unfounded, at least in the case of iron oxides.

Merisi said...

I am so grateful that I found your fascinating writing (via google and contre-jour lighting)!

Caran d'Ache pencils remind me of childhood drawings, coloured pencils in tin boxes.