Oops! I used a bad varnish.

[Desforges]

I painted a portrait some years ago. It was the portrait of a writer, a writer who constantly wrote about his demons. He wrote about what they were doing and saying to him and he kind of painted himself in a corner because he could rarely get away from the subject. His name was Steve Richmond.
I decided to paint a portrait of him inside a mandala-like thing and represented the demons as little dogs playing tricks all around him.
The problem is that I varnished the canvas with a floor vanish. I was clueless about varnishes and wanted it shiny. I ruined the painting because the oil based varnish turned the painting yellow. Is there any trick to remove that coat of varnish without stripping the canvas?
It is hiding in a closet and I miss it.
If I looked at it, I’d get hot flashes.

 

[musket]

Oil varnish dries by polymerization and when cured is pretty much bullet proof. Sorry, but I think you're stuck with it.

 

[Desforges]

Oil varnish dries by polymerization and when cured is pretty much bullet proof. Sorry, but I think you're stuck with it.

Thank you for the reply. That is what I thought.

 

[Hermes2020]

I agree, especially floor varnish, which is usually polyurethane.

 

[snoball]

You could read up on it here.

 

[musket]

Different kind of varnish, sno. Removal techniques for picture varnish won't work on floor varnish, especially if it's polyurethane, but not with hard copal oil varnish either.

 

[snoball]

OK, I thought Desforges said oil based varnish. I do realize that floor varnish has to be durable.

 

[musket]

It is oil based varnish, most likely boiled linseed oil with hard copal for the resin. It's yellowed because that's what linseed oil does, same as in oil paints. Polyurethane doesn't yellow. Picture varnish is quite different. It's designed to be removed. The traditional resins for picture varnishes are mastic or damar, which are much softer than copal.

 

[Artyczar]

I wonder if you could sand it with a super fine grit sand paper and then touch up any parts where the paint gets taken away. Then try to re-varnish it, but that would be pretty tricky. Maybe just stick with it and see how it ages. Maybe it will be okay.

 

[musket]

Sanding will work but would be very dicey.

You could try taking a q-tip and applying acetone to a small, inconspicuous area. If this doesn't work, no solvent will, and it'll be a long, slow process even if it does work. Removing varnish takes skill.

I would leave it alone.

 

[Desforges]

Sanding will work but would be very dicey.

You could try taking a q-tip and applying acetone to a small, inconspicuous area. If this doesn't work, no solvent will, and it'll be a long, slow process even if it does work. Removing varnish takes skill.

I would leave it alone.

I will try with the acetone and Q-tip first,
and then sanding on a little corner ( with glass paper (French)). It is a 4'x4'
If I see that that the result is shitty, I'll live with it as is. Thank you for the replies.
I felt so stupid for doing such a thing like that I couldn't ask anyone until now.

 

[musket]

Take it from one who doesn't care if he never sees sandpaper again-- sanding is an art. I don't know what glass paper is, but you should be using free-cut silicon carbide paper, or if you can't find that, wet or dry silicon carbide used with a non-drying oil, not water. Wet sanding is more of a pain because you have to wipe off the lubricant to see what you've got. Free-cut dry sanding is best. Ordinary garnet type paper will clog from the varnish and leave deep scratches. I would start with 320 grit, followed by 400 and 600-- don't try to do it all at once. The idea is to remove the varnish, not sand the painting. Use a hard felt block. And don't use too much pressure-- let the abrasive do the work.

 

[Desforges]

Thank you, musket.
After the sanding is done, what do I do? Wipe off the canvas with water, then apply another kind of varnish. Which one do you recommend for an oil painting.

 

[musket]

I've never varnished a picture. I know there are numerous proprietary formulas from various companies. I think some of these are non- yellowing, unlike traditional damar picture varnishes. Check them out.

I would be inclined to clean the picture with naphtha, not water, since naphtha will remove any grease, but always do a small test area when using any solvent. It's unlikely to affect oil paint and evaporates fast but better safe than sorry.

 

[Marksmomagain]

My opinion may be of little importance, But, I wouldn't touch it at all. I really like it just as it is.

 

[Desforges]

After the sanding

My opinion may be of little importance, But, I wouldn't touch it at all. I really like it just as it is.

that is the painting before I applied the varnish. It really turned yellowish

 

[stlukesguild]

Musket, what of an exposure to sunlight? I know many old masters would use this technique to counter the yellowing of linseed oil.

 

[musket]

Might work. Would take a long time, and the exposure would have to be many hours a day, uniform over the entire surface. But one can't assume that every kind of varnish is UV sensitive.

 

[stlukesguild]

I had to use the technique with a canvas I had primed using too much linseed oil. It yellowed quite a bit and I remembered reading about how Rubens would place his paintings (those big monsters) out in the sun after applying the whites in the underpainting. If he used the traditional medium it would have been damar, linseed, and pure gum turpentine. His color glazes employed other elements which resulted in something akin to Marogers.

 

[stlukesguild]

Helps to learn from Leonardo. Don't employ experimental media on something you want to last. If only he had stretched or mounted canvas over that big monastery wall and used oils, the Last Supper would likely have survived intact. Or fresco, damn it! Like his great rival.