Varnishing -- first attempt

A layer of varnish is supposed to help protect a painting from dirt, dust and air pollution, as well as mechanical damage (like scratching). It also restores a painting’s original brilliant colours (oil paint tends to become dull and discoloured over time). Varnish also homogenizes (evens out) the final appearance of a painting.

After waiting nearly two years, I was ready to give varnishing a try with my first oil painting, the monochrome Juliano painting. Last Sunday, I mixed the Gamvar varnish (which is a component system consisting of solvent and synthetic resin crystals that mimic old fashioned resin from trees) and then gave the painting two coats this week with a gentle edger foam brush. I took the picture below just after I finished the second layer...

The paint certainly comes alive but I immediately noticed one problem: In some areas, the varnish seems to be repelled. I've highlighted a sample area below in red. Enlarge the picture and you'll see some patches where the varnish has not been absorbed. 

It's a known problem with  varnish. The general consensus is that some areas may contain excessive oil from the last layers of paint applied in the Second Painting phase. It's in this phase that the pure pigment is mixed with oil (linseed oil) to create smooth glasses. Dark areas of a painting tend to be worked over more than the lighter areas and so there's a risk that they'll react differently to varnish (or vice versa).

Today, I tried to fill in some of the pockets with a brush, but that didn't work well, so I've applied a third coat across the entire painting. Fortunately, more varnish has soaked in now and the pockets are less prominent. At the same time, however, the third layer seems to emphasize any flaws in the canvas, such as bumps and knots in weave of the canvas.  A good frame will make a difference though.