I wanted to experiment with "the white canvas" syndrome. I usually paint the canvas a color to eliminate the stark whiteness, using the background color in the painting. This time I wanted to establish a background for a collage, which means I wanted to use paper.
I covered the first canvas with used coffee filters. They are great for texture and color.
The second canvas I covered with pages from a very old book. The pages were brittle and the edges were so old they had turned brown.