Painting Over Dried Painting

[David Carroll]

Hey, what would you suggest for painting over a painting that has dried for 8 months to a year or more? I have some Old Holland retouch and can also make some "real copal" varnish with turps or spike. Is abrasion necessary and is there a widow of opportunity for painting over the retouch?

Oh, and there is no medium used in th existing paint layer, if that matters... Does it?

Many questions... Thanks for your time.

Peace,

[Claudemir Bonfim]

I did this a couple of years ago and I had no problems so far. You'll have to oil it with 1/2 part of lineseed oil and 1/2 of mineral spirits. Use a rag, you'll need just a thin layer, not too dry nor too wet.

[David Carroll]

Well... That's simple enough. I thought I would need to use retouch and/or abrade the surface.

Thanks for sharing.

Peace Out,

[Melanie Peter]

I used the raw linseed oil/solvent to oil out a dried (only a few weeks) painting and somehow got a completely unworkable glassy surface which I then had to sand down and repaint the whole face. I went on to research further and found websites dedicated to the technical side of painting. (http://www.amien.org/) (http://rourkevisualart.com/wordpress/) (http://www.tadspurgeon.com) which pretty much say of oiling out, "don't do it." Mostly, the conclusion seems to be that it's the rawness of the oil rather than the type of oil. Raw oil isn't so good. Tad Spurgeon's site is a long, hard read but worthwhile. The formula I'm using now for retouching is Oil of Spike Lavender (1 part) and my own home-produced walnut sun oil (1 part.) Robert Doak in New York sells sun oil if you don't want to make your own.

I'm certainly no expert, but any of the guys with those websites will talk to you about these issues.

[Richard Bingham]

All of which points to the dismal state in which we find ourselves in the 21st century, with such uncertainties in obtaining a working knowledge of oil paint, its nature, and the relatively simple materials, principles and processes that comprise sound craftsmanship in applying it. Spurgeon's site is a good source of information, thank you for noting additional sources.

Back to the initial question, in general, a painting 8 to 12 months old may be considered to be "thoroughly dry", i.e., all free solvents will have evaporated, and all paint films are firmly "set" into irreversable polymers. Of course, variables obtain, such as the thickness of the paint, the materials used, and ambient conditions.

To continue painting on an aged surface, most painters will require to properly assess the true color and value of dry, sunk-in passages. "Fat" areas that present a slick, shiny, or even tactilely oily surface will be problematic for adhesion of subsequent applications. Both problems are best solved with a sparing application of retouch varnish.

Damar will remain soluble in the presence of solvents used in overpainting, copal will not. Either may be more or less agreeable depending on one's method of working and the end in view. In short, there's nothing at all wrong with going back into a painting that has been "stalled" for months . . . or even years. In fact, it is better practise to paint over a thorougly dry surface than it is to begin painting over surface-dry underlayers, where overpainting can interfere with proper curing of the first layers of paint.

"Oiling out" is a process with limited application, and even less appeal, and no one really knows how to do it, or when to apply it. In the main, linseed oil (and other drying oils) have been considered "varnishes" from time immemorial. When a completed, thoroughly dry painting presents dry, sunk-in passages, no more than a drop or two of linseed oil, applied to those surfaces, and rubbed in with the heel of one's palm with enough vigor to generate warmth from friction will correct the problem. It is no less than miraculous how far a drop of oil goes in this process. The result is that the lean passages are thus "varnished". Applying a 50/50 mix of oil and solvent with a brush or daub is a different thing entirely, and invariably deposits enough oil to be deleterious to the painting as it ages.

Since the question is actually how best to unify the surface of a completed, thoroughly dry picture, application of an appropriate final varnish is the best solution, since it's really quite doubtful those "sunk in" passages actually display the results of paint so underbound that an additional application of free oil is called for.

[David Carroll]

Good stuff... Thanks! I'm thinking spraying a thin copal turps mix. Is there a window of time you would want to paint on top of the retouch varnish? I would like to varnish the whole piece at once and proceed in painting it in sections. My goal is to finish it early next month.

Happy Thanksgiving...mmmmmmm...Turkey .

Thank You, Peace,

[Richard Bingham]

You can paint on the retouch varnish as soon as it's dry to the touch. Retouch varnishes should be reduced to the point of depositing as little resin as possible to be effective, and applied as sparingly as possible. As to the "window" an ideal application will sometimes allow a dead passage to "sink" again if left too long. Spot applications are better than varnishing the whole piece, unless the painting is small, and you intend to work "all over" rather than in passages.

[David Carroll]

Thank You, Richard.

Peace

[Richard Bingham]

My pleasure, David.

Everyone, Happy Thanksgiving!!

[Claudemir Bonfim]

Dear Melanie, I'm sorry about your experience. Mine was fine.

And David,

Do not use Damar, it yellows a lot with time.