Snag some paper
The Project Dogwaffle demo has some paper grains that can be ported to AR. Select a grain from the paper panel, color in with a dark color to make the grain show up, then cut and paste a screen capture into a photo editor. Select an area of the picture that only has canvas and crop it. Save that as an AR paper grain. I used one of these papers in the attached example. I'm sure the same can be done with many other programs that have papers.
Good call Michael. It's pretty exciting to be able to create our works on anything from fine linen to yesterday's grass clippings thrown on a scanner.
"Teach, Learn, Thrive"~DM