I’m currently taking a class on mixed media and was intrigued when teacher Susan Hostetler mentioned “mock frescoes”, made by painting gouache into still-damp spackle or joint compound slathered onto cardboard or other heavy substrate. I decided to try it. My first attempt was a simplistic sugar bowl sitting on our kitchen table. My quick contour was misshapen, so I touched it up with some water-soluble pencils, moistening the marks to blend them into the gouache.
I then plopped down a seashell (interesting shape though dull colors) and tried again. I was happier with that one, though disappointed when a little flake popped out sometime later. Maybe a fixative would deter this type of defect — will have to research it. . . .