Why is my retouch varnish not covering evenly?

Materials Oil Painting
1

I just finished applying Grumbacher retouch varnish on a 5x7 oil painting (Gessobord) and it seems to resist at certain places. Will a second coat do the job? I don’t want to apply the second coat until the first is dry. I’m really pleased with the areas that are covered, but that’s not how I want it to be seen.

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Hi Patricia, some parts of a painting will be more oily than other parts, just as some areas may appear more matt ( sinking in), so oily areas will resist varnish, called beading up. It’s to do with surface tension and the fact that a too slick surface will not take varnish easily. I would experiment with a throwaway piece to see if a little agitation or light scrub action with the varnish will break the surface tension. A second coat often sorts out the unevenness, but experiment to make sure.

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3

I find this happens sometimes, although I dont use retouch varnish, I use gamvar. I find that if I let the first coat dry and then apply a second coat, the areas that resisted the first time, fill in on the second coat. Not sure why this is and I always apply two coats anyway.

4

Retouch is supposed to even out the shine while you are painting so you can see your colors better (not as a final varnish) so it is odd that it is not working. Gamblin and others recommend oiling out before varnishing so the varnish will be applied evenly. I have tried this and it does work.

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By oiling out first, do you mean brushing on a coat of linseed or other oil and then varnishing right on top of the oil?

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I followed the directions on Gamblin’s website: using Gamblin Galkyd medium mixed with a little Gamsol to thin, brush on thinly being careful to not let it pool in areas of thick paint and let it dry thoroughly. Then varnish with your final varnish. I use Gamblin picture varnish which dries very quickly.

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Catherine, I agree with Andrea on the oiling out - check out the tutorial at Gamblin for oiling out. https://www.youtube.com/watch?v=zFJEzZkuls4
And I’ve found that the darkest darks are the main part of the problem. If the painting is skewed to the light end of values it usually isn’t needed.