Elmer's Glue on Canvas, then paint the whole thing. I have totally done this, but with a hot glue gun. Elmer's Glue seems to be a better idea since hot glue leaves behind strings and is harder to work with.
DIY High End Wall Art- Dry brush ombré painting. Start with it dark at the top and drag it downwards, don't add more to the bottom than what is drug there. Then take gold leafing and pat it up top. Craft and DIY Projects and Tutorials