Can I use acrylic medium retarder gel like a varnish? Yes I'm painting with acrylic. The ingredients on the jar say "acrylic polymer emulsion"
So here's what I'm trying to do; I have a painting that I like but I want to add thin detail lines that need to have good flow to them so I'd like to wipe them off (while still wet) if I slip up. But as it stands I have sanded down a bit of the background and if I wipe something off now it will stain the canvas that's exposed from the sanding. So can I put a thin layer of Retarder Gel over the whole thing to keep parts of it from being absorbent and staining? Would that ruin my painting at all?