In the Fall of 2015, some friends and I participated in a pigment-making evening, where we made pigments from plants as it would have been done in the Middle Ages. Because most of my colleagues focus on water-based media, they wanted to see how the color would change when it was mixed with and applied with oil paint. I mixed each with a walnut oil base, and did a strip of each by itself and with lead white.
Weld on eggshell
Weld on alum
Brazilwood on eggshell
Brazilwood on alum
Orchil on plaster
Verdigris in damar
Straight walnut oil
I cut the strip in half and placed one half in a dark location and the other in sunlight, and I'll share that later. What I have noticed is that some of the colors, such as the orchil, is starting to bleach in the sun, but the walnut oil has turned an obvious yellow in the dark.
