Folding the corners of stretched canvas: it’s just a detail, but it’s one many painters can’t seem to get right. I’m sure a lot of them just don’t care. But for the perfectionists out there, here is a method I have found that is simple and neat:
As a further refinement, one can use a rubber mallet or a scrap block of wood to tap the folds down even tighter. When you size the canvas, be sure to apply some to the sides as well as that will tighten the folds even further.