The substitute for Tyvek not only doesn't take paint well, it resists mediums and glue. I finally tried Gorilla glue on it so tomorrow I will see if that holds. On a whim, I tried ironing it like Tyvek and found that even with the iron set on linen heat had NO effect on it. Phoey. It will work for this picture though as I am making dandelion blooms and leaves from it. I wanted to glue a wire between two sheets to make the leaves bend.
The greens sprayed well and I finished the landscape with a brush. I have the base of the blooms glued on so the petals will stand away from the canvas when I apply them. I still have to decide whether to paint the dandelion at seed or devise some 3D way. Suggestions have been Halloween webbing torn up, or cotton torn up. If I go 3D I will use a cork for the base of the seed ball.