I’ve become fascinated with casein paint, mostly because it’s water soluble and can be used like a transparent watercolor or an opaque gouache or even like a thicker, heavier acrylic. It also dries to an impermeable surface which can be left alone, varnished for an oil painting appearance, put under glass, or displayed in a frame. In other words, it’s versatile.

I bought a six-color kit and practiced a little on my watercolor paper. Used thinly, supposedly it won’t crack after it’s dried. I’ve learned a lot in less than an hour:

• Casein dries on the palette quickly. It turns thicker and thicker until it goes from a smooth, velvety texture to a gluey texture. At that point, you need more water to get the paint onto the surface, and that extra amount of water will thin the paint so it’s not as opaque. I’m going to experiment with a wet palette to keep the paint fluid for a longer amount of time.
• Casein is truly opaque, which means one layer will totally cover the first layer (when the first layer is dried). This is so different from watercolor that it’ll take some thoughtful practice to get used to it. For example, when painting the windows on the houses, I kept painting around the edges. Only at the end did I realize I could paint directly over the wall of the house to create a window.
• Casein can be mixed on the palette, but when it’s still wet on the paper, it can also be mixed on the surface. I think this is a matter of skill as the paint doesn’t blossom like watercolor. It’s far more subtle.
• You can use two colors on your brush to create super cool effects.
• White doesn’t appear as pure white when layered over other colors, at least not for me. It seems to show color beneath. I suspect you need to use fairly thick paint with nearly no water to get white to obliterate the color below. So, perhaps, when the painting is nearly done, putting down a fresh bit of white paint to use is the best bet.

The little painting is from a 1950 book by Henry M. Gasser, Casein Painting: Methods and Demonstrations. This first example is using casein watered-down, more like transparent watercolor. I simplified it tremendously, not wanting to paint two dozen teeny houses. It’s funny how crooked my houses are–can you tell I did this at the end of a very long day? I was super excited to try the paints and wasn’t content with doing the color sampler.

Artist James Gurney is a fan of casein and is probably the reason why I bumped into it in the first place. He writes about it on his blog and has numerous short videos painting en plein air. Truthfully, although artists use this medium, there isn’t a tremendous amount of current information about it, even though it’s the oldest known paint and was used in ancient cave paintings.