I just use a spray varnish (Grumbacher professional top quality non-yellowing oil paint varnish) on it at the time it’s sufficiently dry. As long as I’m not working with truly major layers of paint, I’m guessing that priming the paper isn’t genuinely that crucial – correct? It is great to http://art-prints76431.ivasdesign.com/12468024/paintings-on-paper-no-further-a-mystery