I was doing a study of Roy Lichtenstein in oil on a white canvas (not prepared in any way) as practice. I've just completed the black, and now a friend wants to buy it. So the question I have, is that after it has dried, do I just apply varnish to the entire canvas, including the unpainted portion? Will that look ok?
Picture attached.

Comments
Love Lichtenstein!
Yes. The white canvas is primed (sealed) and gessoed (usually with three coats at the factory).
Applying varnish to the whole thing will look great.
But …..
Lichtenstein looks even better with colour, Ben Day patterns and text in a bubble.
https://maddoxgallery.com/
Dots galore. These can be photoshop printed as sheets on transfer film and swivel cut to shape. Easy Peasy.
Denis