Here are two views of a textured canvas that’s ready for watercolor. One lit to show the drawing; the other to show the amount of texture.
I use Golden’s Fiber Paste, brushed onto the surface and allowed to dry at least 24 hours. The jar says the product is “produced with 100% Acrylic Polymer Dispersion,” which somehow ends up acting like (very rough) paper.
After experimenting with fiber paste on paper and canvas, I find the canvas to be a better surface for the way I paint – paper was too absorbant. I’ve used both hard canvas panels and the pre-stretched variety. Brand and surface prep don’t seem to matter.
One tip: ink the drawing before applying the paste, and use a permanent marker!