Thursday, March 26

Colors and Pigments: How to Tell the Real Color from Different Manufacturers

Today’s Image

Today I’m following up on my last blog, Art Blogging: A Learning Experience, with a little information on the science, nomenclature, and categorizing of colors, which I found to be informative, and I hope you do, too. For many artists, understanding color-- how to mix, capture, and create with it--is essential. However, as in life, there is often more to something than meets the eye, and that is the case with the art and science of color. Today’s Image is representative.

What got me onto this subject was the search for the meaning of the term quinacidrone, which I covered in the last blog. I also found out quinacidrone can be organic and synthetically obtained, although I didn’t find out how, and that, in addition to red (great reds, one site said) and violet, it also makes colors rose and magenta. But I’m getting ahead of myself.

There is way, way more to learn about the science of color than this brief discussion could ever cover, but I hope you find it interesting enough to become better informed. I spent several hours online and found no one, specific site that tells you everything about it (at least not for free), but I did piece together a very basic understanding. Also, the industry uses the term color to cover pigments, used not only in making of paint (and a lot of other materials), but also in making dyes.

My first discovery was the site for the Color Index International (CI). There is always a professional group, society, or association for every consumable product, and for color there are two: Society of Dyers and Colourists and American Association of Textile Chemists and Colorists. The CI is, as stated on the site, “the definitive guide for anyone who needs to know details of which companies manufacture and distribute dyes and pigments, or for anyone looking for technical details of these products.” They don’t give out this information freely (or free, for that matter; you have to become a member and pay dues to be able to get the information). They do at least give you a sample of what you’ll get if you pay up.

The example provides the following technical information for what they call a “fingerprint” for each color (the example is for Pigment Yellow 1):
  • Generic Name--their official name (I guess) of the color; e.g., CI Pigment Yellow 1 (not to be confused with the art-y name a manufacturer may give a color, such as sky blue light).
  • Constitution Number--don’t know how they come up with it, though.
  • Chemical Class—Monoazo (I think you have to be a chemist to know what this means, but I did recognize the “azo” part, which I’ve seen as the color Azo Yellow).
  • Shade—Bright Yellow (even I can understand that).
  • Discoverer—H. Wagner, 1909 (never heard of him or her).
  • First Product—Hansa Yellow G (maybe Hansa was his or her first name?)
  • CAS Number—Does not say what this is.
  • EC Number—No clue on this number either.
  • Classical Name—None listed for this one (how about Sunny Yellow!?).
  • The chemical diagram--This is similar to the “chicken wire” diagrams you may remember from high-school chemistry.

Some of the above information appears on the manufacturer's product itself. And, comparing that information is the only sure-fire way to tell if two colors from different manufacturers are the same.

There’s so, so much more on this subject that I won’t attempt to cover it here. However, one website I found by David Myers is excellent. It’s The Color of Art: Pigment, Paints, and Formulas, and it gives a great overview about all of this (and more, such as opacity, light fastness rating, oil absorption, and toxicity). also has brief, but easy to understand, discussion about this on their site as well. You should check these out to learn more.

So, next time you shop for French Ultramarine Blue, just remember there's a whole lot more that went into that little tube of paint than you probably realize!


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