I did a demonstration and talk today in East Boothbay, Maine. A very beautiful place. When I do demos I encourage the crowd to bombard me with questions, partly because if they don't I get hung up in the painting part of the demo and don't talk enough, but also because with a little encouragement they ask about things they want to know about, and if I know what they want to know, I can be of more use to them. I am a downloader, not a cheerleader.
One of the questions that came out today was something I think I have written about, perhaps in passing, but I think I will spell it out clearly tonight. I was asked "is it OK to use Liquin (alkyd medium) as a final varnish?"
The short answer is NO, but I will qualify that a little. Liquin takes care of some of the problems that one uses a varnish to solve. It does bring up the "dried in" (or matt ) areas of a painting. Some passages in a painting lose their oil into the layers below them and become flat, particularly the darks. Putting a coat of varnish or Liquin on the surface restores some reflectivity and returns the note to the color that it was when freshly applied. That takes care of that, and if you need to send the painting out to a gallery the problem is solved. In fact it puts a nice, even, satin finish on a painting that looks good and is easy to light consistently. I do it myself on occasion.
However Liquin does not do the other thing that a varnish should do. Here's what that is. Picture varnish is like the wax your dad used to put on his Country Squire wagon, it takes the road dirt and the beating instead of the paint on the car. Once a year or so dad would strip the wax off the car, taking the grime and Truman era strontium 90 with it. The wax shielded the paint on the car and could be removed and then replaced. Picture varnish works the same way, we put varnish on a painting as a bulwark against the dirt and chemicals that foul our squalid world. A generation or more down the road some restorer, using solvents, will strip the varnish from the soiled painting, and put a new coat on. The grime, and corruption are removed with it.
But Liquin becomes a part of the paint film, it can't be removed. It becomes chemically a part of the painting rather than a glistening protective condom stretched over it's surface. Therefore it is OK to use Liquin as a short term solution to the problem of making a painting presentable in the market, but the painting should still be varnished at a later date.
Now you may think "What do I care, won't I be dead by the time that happens?" Maybe yes or maybe no, but you owe it to your clients to make a painting that your clients children and their children can enjoy. Your customers buy your art with that expectation, they see the old paintings in the museum and assume that if they buy your painting it will last a very long time too. It is a matter of making a quality product. And
A painting has nothing to recommend it other than that it be well made.