Preparing Canvas to Prevent Yellowing Over Time? What coat can I apply on a gallery canvas (before painting on top of it) to prevent it from yellowing over time?  I'm planning to leave some parts of the canvas unpainted.
The quick fix is a sealer so the tannin or stain can't penetrate through. Stain blockers that are oil-based primer/paints, spray shellac, polyurethane, or even wax.