I added a new column to my paint inventory sheet: pigment numbers.

What’s a pigment number, and why does it matter for historical paint?

One, each pigment has two identifying codes – the Colour Index Constitution Number (or CI number), and the Colour Index Generic Name Code. The CI Generic Name Code starts with P (for pigment) then B (for blue), R (for Red), W (for White), Bk (for black), Br (for brown), G (for Green), O (Orange), V (Violet) and Y (Yellow). If an N is in front, so NY or NR, it means it’s a naturally derived pigment like Stil de Grain or Cochineal.

Why does it matter? The CI numbers help clue in an artist on how a pigment is going to behave. Some pigments, like some of the more natural yellows, can fade relatively quickly. The CI numbers also help flag other parts that can be important to painters, like transparency/opacity, tinting strength, granulation (especially in watercolour), drying rate, lightfastness, and permanence.

It can also help with figuring out substitute colours in case one has been discontinued. Some paints have the same pigment, but it may be sold under different names. For example, PR83 (Alizarin Crimson) is sold under Alizarin Brown; Alizarin Carmine; Alizarin Crimson Dark; Alizarin Crimson Deep; Alizarin Crimson Golden; Alizarin Crimson Lake; Alizarin Farben; Brown Madder; Carmine (hue); Madder; Madder Brown; Madder Carmine; Madder Lake; Madder Lake Deep; Permanent Crimson; Rose Madder Deep and a lot more I didn’t have room for. Same pigment, different colour names.

And sometimes, the names are the same, but they look radically different between brands. It’s no secret that paint companies will mix pigments together to create new and exciting paints. For example, Pure Blue from Holbein uses PB17 (Phthalocyanine Cyan), but Primary Blue from Winsor and Newton while optically similar, uses PB15 (Phthalocyanine Blue). Compare this with Schmincke who uses a combination of PW6 (titanium dioxide) and PB15:3 (Phthalocyanine Blue BGS) in their Primary Cyan formulation! And yes, the tinting strength and finding out tthe way the paint behaves both in the short and long term can be found just by looking up a handful of numbers (PB15 and variants and PB17 can age poorly over time, and PB15 especially is prone to granulating.)

The really nice thing about using pigment numbers, and how it comes into play with SCA stuff is that you can use those pigment numbers to see if the pigment is right for the project you’re working on. For example, ultramarine blue comes in both natural (no CI name) and synthetic forms (PB29). Both work well for SCA applications, but if you’re really trying to push your artistic boundaries, you can try to find a paint that uses real lapis lazuli (also called lazurite) in the formulation. If you find a CI number on the label, the paint is probably made from the synthetic stuff. (also, synthetic doesn’t mean *bad*. It just means made by humans, and that can make it cheaper and easier to get.) There are enough working differences between the two pigments, including the possibility of pyrite inclusions in real lapis that can make the finished paint sparkle slightly, which the synthetic would not have. Of course, if you’re making substitutions for safety, knowing the pigment numbers can also help by finding similar ones nearby.

So, where do you go look up these numbers? Every commerically made tube of paint will have a set of numbers on the side. If you want to do comparison shopping through, there are a couple websites out there (that I’ve talked about before) that can be useful. One is The Art is Creation, Color of Art Pigment Database. The other, which I find even more useful is ArtistsPigments.org, which breaks out pigments by brand, colour, shade, and even medium. Using both of these tools in your artist practice can help explore paints that work for your individual practice.

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Updates to my life post-Being Human Festival!

It was great! We hosted three local high schools, got to show off the treasure that is the Quintanilla Murals, and I got to make a video that showed not only my own personal practice, but I also got to talk about pigments and some of the science behind them, with features from the sponsoring university schools (SSE, SHSS). I had a great time, but my goodness, it ate my life for a bit.

I also have a few new books that I’m excited to go through. One was a Kickstarter for Inks and Paints of the Middle East, which I’m waiting for the mail to bring to me, and then I also ended up getting Gold from Newton’s Apple Tree: Historical Recipes for Natural Inks, Paints, and Dyes, which has some modern practice stuff (including recipes from the author) and some historical stuff. Since I’m new to laking pigments, I want to make sure I have everything I need before I get elbows deep in the mess.

And that’s kind of where we are right now. I’ve had a lot of life in a very short period (getting a grant in less than three months of starting a job at a university is crazy-pants. Getting a grant at a university, speaking at a programme at a world-class museum, and then hosting a series of three programmes in the span of five months is sheer insanity).