“It’s been a problem for a very long time. At least according to the historical record. Blotchiness. Sinking in. Dead spots. For oil painters these are well known terms, conjuring up images of skin disease as much as painted surfaces, but whatever words are used the implication is clear – it’s an undesirable nuisance; a loathsome interloper in the creative process. tAs for what to do about it, the traditional and handed down remedies have run the gamut from oiling out with different recipes to the frequent application of retouch varnishes of various types. What is the current thinking about all this? What might be the cause and best solution? What follows is not an exhaustive treatment on this topic by any means, but it shares results from some current testing and offers what we feel are best practices given what is currently known.” -Sarah Sands (Golden Artist Colors)
I really appreciated you posting this article, Anthony. It sent me down a path of emailing Just Paint for an evaluation of my painting process steps, as I have oiled out on some of my paintings following the process of Gamblin (https://www.youtube.com/watch?v=PvY_rl1dmkU), which stresses wiping off the medium as soon as it is applied. After I received the informative email from Just Paint (which re-emphasized the points shared in Sarah Sands article) about the conservation hazards of oiling out, I emailed Gamblin to see if they had any research to back up their recommendation of oiling out with Galkyd during/after the painting process. I am forwarding their response to me and curious if you or anyone else has any thoughts. (As an aside, Just Paint recommended Retouch Varnish as an alternative to oiling out (as a final coat), but Gamblin recommended oiling out to Retouch Varnish). Thanks in advance for any light you can shed on the conflicting information!
_Dear Josh,
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_Thank you for contacting us.
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_Gamblin Artists Colors has recommended oiling-out using Gamsol-thinned refined linseed or alkyd resin (Galkyd) for well over a decade. Because oil painting has used drying oils for several hundred years, the art world has a well-documented history of its long-term color stability. We know that all drying oils yellow to some degree and more deeply in dark or low-light storage. We also know that the same paintings exposed to strong, indirect sunlight will return to nearly their original color before yellowing.
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_Alkyd resin was first manufactured in the early 1930’s, so the industry has many decades of use to know the material’s aging/yellowing properties. Galkyd has very little effect on color when used as intended. Please refer to our newsletter on whites, in which we studied the color shifts in dry white paint layers: Getting the White Right with Gamblin - Gamblin Artists Colors We included our whites mixed with 20% Galkyd in this article.
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_If Galkyd is used in greater percentages with oil colors for glazing techniques, you can expect more of the amber color of Galkyd to influence the color from the tube. As with all oil mediums and binders, this color can increase if the painting is stored in the dark (see also Henry Levinson’s study, Yellowing and Bleaching of Paint Films, referenced in the aforementioned newsletter).
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_We can also say that, anecdotally, we have never had a painter using the oiling-out technique contact us with yellowing issues. We have heard many stories of excess yellowing when a painting medium was incorrectly used as a varnish. Oiling-out has never been an issue because thinning with Gamsol and wiping away excess medium ensures that only a nominal amount of oil remains on the surface. The net result is a unified surface quality and improved color saturation without yellowing. We feel that this is more beneficial that applying a retouch spray. When using retouch varnish, a thin layer of varnish is put in between paint layers. When oiling-out, binder soaks into existing paint layers crosslinking with the paint film to become one homogeneous layer. Unlike retouch varnish, an oiling-out mixture will not be susceptible to potential softening and removal down the road if the painting requires cleaning.
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_I hope this email helps. Please let us know if you have additional questions, we appreciate your support of our materials.
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_Kind regards,
_Mary
