Marbling Canvases

This will be step one in an entry to 6 x 6, an art show in Rodchester NY. I'm going to further paint on this wooden canvas.

Here is attempt number two:

I learned that if you don't liberally coat the entire surface with alum and let it air dry, especially on primed fabric canvas like this, the paint won't stick. 

So these drip marks are from where the alum was spread and dried, and you can see the paint only stuck on those areas. This is a happy accident because now I know I can use alum for masking effects with marbling.