This is a question I’ve heard lots of artists talk about.
It’s easy if you can have your paintings sit in the studio for 6 months or so. Just let it dry then varnish the painting.
But what if the painting is sold, a commission, or needs to be shipped to a show or gallery. Of course, the painting needs to be dry to the touch before it can be shipped. Some paintings with thin paint, fast drying paints will be dry in two weeks. But it can take up to 6 months for it to dry enough for varnish. The painting must be dry to the touch (not soft) before being varnished.
In the past I did varnish some paintings too soon. What I found was that the painting always remained “sticky”. It picked up lint like crazy. Now I usually will first use a light coat of spray varnish if the painting has to go out quickly. I use gamvar as a varnish diluting the varnish with gamsol, 3 parts varnish to one part solvent. Then I can varnish it sooner, just making sure that the paint is not soft to the touch.
Living in Arizona with our famous “dry” heat the paintings will dry sooner. I have even put a painting outside in the sun for a few days. That dries it very quickly. Of course, the summers here will dry everything out. I guess that’s one advantage with the summer heat here.
Gamvar can also be diluted with more solvent, 5 parts solvent to 1 part gamvar. That will give you a retouch varnish. I will put this or a spray retouch on as a last resort rather than nothing. I like varnish on a painting to unify the dull and shiny areas and to bring out the richness in the colors. In this case I will give a note with the painting and explain to the client that in 6 months or a year the painting can be permanently varnished. It is usually easier to let the client use a spray varnish. I give them instructions and tell them the kind of spray if I know they will be varnishing the painting.
You can also use the time frame as a way to reconnect with your client. For years I have done the Celebration of Fine Art in Scottsdale. I will often sell a painting “off the easel” or shortly after. In that case, there isn’t enough time to permanently varnish the painting. I tell the client that I’m not able to varnish it, but that I will come out to their house or they can bring the painting back to the show the next year. Then I will varnish it for them. I make a note in a file box with the month they can have their painting varnished and send them a card or call to remind them. If the client isn’t in the local area, I send them a card to remind them with instructions on how they can do it themselves.
I have found that people are appreciative that I give my paintings the proper care by waiting. They also like the fact that I care about them enough to remind them. This has worked out to be a positive, not a negative.
When the painting is going to a gallery, the very least I do is spray a light coat of varnish on the painting. That may be all the time I have before it is shipped. But of course, again, it will be dry to the touch before shipping. I have heard of artists painting a medium on their paintings. Mediums are not designed to be used as a varnish. Mediums can’t be removed from a painting as easily as a varnish without damage to the painting.
I hope this helps you with your varnishing time frame.