This site is amazingly comprehensive on the subject of watercolor pigments and colors. The author notes that lightfastness (both his and manufacturer’s) should be taken with a grain of salt–if you want to be really sure, test your specific tubes of paint.
I don’t really agree with him that modern synthetics are better in all ways than historical pigments, but hey, I’m in the SCA. I think that it’s important to at least understand the way historical pigments work–for example, a medieval illuminator would not typically have mixed red lead and white lead because the paint would probably turn black (in theory, they can be mixed if absolutely free of sulfur impurities). So mixing a modern orangeish red with titanium white to get a light red would produce a color the medieval illuminator wouldn’t have. But I also find that the historical colors do look subtly different, and working with them provides me with a historical experience that modern substitutes never can, even if I mix them myself.
Am I going to use saffron and glair on a piece for someone else? Absolutely not! But I still want to try it out on an intentionally impermanent piece for my own education. And I don’t think using less lightfast pigments on pieces that will not exposed to light–such as books–is a bad idea. Medieval manuscripts have, after all, retained their beauty for centuries.
Anyway, I’m working on a chart of historical pigments and modern watercolor and gouache equivalents (both authentic and substitute), and I think I’m going to have to list by major brands. It’s an interesting project. For some things, such as vermilion/natural cinnabar, it’s easy to find a universally recommended substitute (cadmium red light). For others, I’m going to have to mix up the period paints and try to figure out what I’d use. And some are just going to be a shot in the dark–synthetic dibromoindigo seems to be impossible to find, so I’m going to have to guess at possible transparent substitutes for Tyrian purple based on photographs (and Tyrian purple was hugely variable based on both mollusc species and preparation technique).
I really want to put some of the Daniel Smith PrimaTek colors on a microscope slide and check them out with a petrographic scope now (assuming that would work with ground minerals rather than thin sections). I’m really, really skeptical that some of those colors are genuine minerals, particularly the rhodonite, and that should be easy to tell under a scope. I might even be able to tell with my old kid’s scope, if I still had it. I’ll have to see if I can check that out….
In other news, I’ve been doodling with gouache a lot, and my brush hand is a LOT steadier, so my next attempt at illumination won’t be as wobbly. I need to work on my Carolingian spacing, though. Yesterday I painted my first super miniature portrait (about 1.5″ across, round, because that was the only decent frame I could find–16th century miniatures were usually larger). Of course it’s in gouache and not oils and it has issues, but it vaguely looks like me, if I were darker, Spanish, and didn’t ever smile. Close enough for 1.5″, I think. I need to paint one of Melchior and varnish/seal them so they look less gouache-y and acrylic-seal the brass frames so they won’t tarnish and then we can wear twinky miniature portraits of each other.
I’m hoping to have some time over spring break (between sewing, embroidery, work, and homework, not in that order) to play with the period pigments some more and make glair and tempera.