This is a fairly quick study (probably around 80 minutes) of a kingfisher.
I used graphite to sketch the basic shapes on regular, cheap chipboard then sealed the drawing with a very thin layer of Liquitex Clear Gesso. I then went straight on with casein. (I used my regular 11-color palette—which I can detail if you're curious.)
After about an hour, I placed my palette in a big resealable plastic bag and let it sit for about 24 hours.
When I came back, the paint blobs were still wet and the mixtures on the palette only needed a little work with a wet brush to be workable again (like you would expect gouache to be).
I loved, LOVED the paint' handling qualities. It really is like nothing I've ever used before. And the richness of the pigments is still stunning.
So... yeah. Next time, I'll use more gesso (or matte medium) to really seal the board so the fibers don't lift as much. (It's a pretty cheap surface that was never meant to be painted on, so... no harsh feelings.)
I'll keep you posted.