"I'm confused about how illustrators work in oils where it's recommended that works are not varnished for 6 months. Does an illustrator get his painting done and then send it off within a few weeks without varnishing after it is dry to the touch...then varnish when he receives it back? What about commissions? Do you tell a client to wait for six months to pick up their landscape or portrait?"
Here are my thoughts, and I welcome yours in the comments:
I usually paint in oil fairly thinly using an alkyd medium (Liquin), so it nearly always dries overnight, or at the most in three or four days. If I want impasto texture and I'm on a deadline I will pretexture with quick trying priming medium. (Previous GJ post on paint texture and pretexturing (part 2) and (part 1).)
If you want to use thicker paint you can put a few drops of cobalt drier into the blob of white paint and a thick passage will set up overnight—or in a few days if it's really thick. Since white is in nearly every impasto mixture, the drying agent finds its way into all the thick passages. Don't use much, though, because it will discolor the mixtures.
Occasionally I shine a low wattage light bulb on the painting (about two feet away) overnight to hasten drying, but you have to be careful on any kind of panel to be sure it doesn't warp. Some people construct drying boxes, with low wattage bulbs to serve as heaters, which warms and dry a painting evenly.
If you have the time on a gallery painting or commissioned work, you can apply thick paint with a slower medium and wait out the drying time.
You do have to wait a few months for the finish varnish. If you varnish too early the wet paint will soak it up and still dry matte. This would be a problem for plein-air paintouts or gallery work if you don’t allow time for it to cure. If you know the buyer, you can arrange to come by and varnish it for them later.
Shipping work to illustration clients is no problem, though. If there is a passage that remains wet, you can build a crate with spacers (or ship it framed) to avoid having something touch the paint surface.