Per the Richeson site, to make your own casein paints with your favorite pigments: “Mix Shiva Casein Emulsion with powdered pigments: Spray some water on your palette and scoop out the pigment with a palette knife. Mix thoroughly into a paste and add a few drops of Shiva Casein Emulsion. Mix again, and you’re ready to paint.” http://www.richesonart.com/products/paints/richesoncasein/richcaseinfaq.html
I’m wondering if, instead of mixing the casein emulsion with powdered pigments (which I don’t have on hand), I can mix it with the array of tubed watercolors in my favorite pigments. These tubed watercolors obviously contain other things besides pure pigment, such as gum arabic and glycol.
Thanks, Kristin. I don’t know the Ph, but note that the Natural Pigments forum recommends that when you mix your own casein that you aim for 9.0 – 9.5 (relatively high Ph). I sent a question to Richeson about this. But now my question (after some unsuccessful research) is how do I know which pigments are sensitive to a high Ph? One site mentioned lake colors, but I’m having a hard time finding any other specific info. http://www.jcsparks.com/painted/pigment-chem.html
If the sensitivity to high Ph shows up right away (e.g. if the red colors all turn to blue) then that’s no big deal, as I wouldn’t use the paint if it’s the wrong color. But if the color changes over time, that’s obviously a problem. It seems like this would be a problem regardless of whether I’m using the pigment in a dry form or from a watercolor tube.
Here’s the similar answer from the helpful folks at Richeson:
The Binder in the Watercolor may not interact with the emulsion well – and could create issues. Regardless – it would result in a different paint – not Casein. Could be an interesting experiment! Wish we had a better answer.
You probably could? Although I would check the pH of the casein paints you are using…some of your watercolor pigments may be sensitive to higher levels of pH (fresco painters know all about this issue).
Both Ralph Mayer’s book and Mark Gottsegen’s text list pigments that are sensitive to high levels of pH. We can also reach out to our contact at Richeson to see if they wil answer your question on this forum.
Also, one of the virtues of casein is that over time it becomes insoluble in water. Using watercolors rather than pigments will negate that to some degree.
