This is a little study I was working on last night. You'll see this image again, I'm sure.
It is painted with casein paint on paper. Casein can be thinned and painted similar to transparent watercolors, but it is a bit more opaque, like an oil paint, acrylic, or gouache.
This hotel is in Venice, Italy, and why I took this pic was because of that curely-q shadow cast from the light fixture. (My shadow is all wrong, by the way, . . . it was getting late. . .)