Hi MITRA, 20211022_005347.jpg
I began a large oil on linen several years ago, and picked it back up again when I received grant funds to complete the project.
In a case of “what’s done is done”, since I’d had good luck in the past with cleaning spots/stains off of an in-progress painting with artist’s recified turpentine then cleaning off any potential residue with OMS, that was the approach I took earlier this week on one area of this painting. As soon as the solvents dried, I saw a faint white residue that was comprised of many whitish “rings.” I had used a freshly-laundered rag that had previously been used for oil painting, so I came back in with another treatment of OMS and a new clean rag, thinking that perhaps a thin veneer of oil that made it through the laundering process had been deposited by the rag. It got a little better (and when the surface was wet with OMS it looked fine), but once the OMS dried, the rings were still there. It kind of looks like a patterned version of sinking in. I wondered if something migrated up, or if I disturbed the binder too much, etc when I cleaned the surface with the turps?
I use a high-quality paint with a walnut oil binder, so there shouldn’t be any impurities in the paint itself. I also follow the fat-over-lean rules, and never adulterate my paint more than 20%. I had started this work with a solvent-based alkyd oil medium, then switched to the walnut alkyd oil medium, though the affected area is comprised of just a couple of layers with the original medium. I do plan to overpaint, though I had been planning to just add highlights and shadows to this region rather than overpaint the entire area — though if that’s what I need to now do, I will. I’m also wondering if varnishing later will take care of it?
I’ve attached a photograph for your reference. It looks like the whitish shapes settled into texture made by the hand-applied acrylic dispersion primer “gesso”, because the paint layers themselves are fairly smooth and applied mechanically thin. (Incidentally, this surface texture is only visible by zooming in on the photo — it isn’t apparent to the naked eye or touch — and it seems like if the turps bit into the paint layer enough to create the texture, that it would either have revealed the underpainting or the white primer.)
This particular painting is part of a larger project for which I have a deadline. It is a very large canvas, so for both monetary and time reasons, starting over isn’t an option. I definitely hope that you won’t think it is necessary.
Thanks in advance for your help and advice. I do hope you’ll have good news for me and that this won’t cause any adhesion problems down the road. Fingers crossed that it is easily remedied.
Many thanks for your replies, Brian — I appreciate your patience with my response as I got quite busy there for awhile and didn’t have time to follow up until now.
The “situation” was indeed difficult to photograph. Essentially, once the turp evaporated that I had used to clean the surface, it looked like I had applied an extrememly thin, dull white glaze with my rag.
It sounds as though eventual varnishing will mitigate this milky appearance wherever I am not overpainting. I just wanted to check that overpainting wouldn’t be an issue here, since I do need to apply the final highlights and shadow layers to this passage of midtone colors.
Also, another issue I have is that a very small area that essentially ended up being rather accidentally sanded as I tried to remove a small, stray glob of paint that had fallen when I was working on the top portion of the canvas, but I didn’t realize it until it dried. I might have left it but I knew it was violating fat over lean. I assume I can just paint over this area without issue, following the fat over lean rules regarding the surrounding layers? I’d say it’s maybe half to 2/3 the size of a US dime, so in the grand scheme of this large canvas, it’s an extremely small spot. I know some artists sand layers as a routine part of their practice — the airborne pigments are likely the main concern there, right?
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The photos do not really show enough to really give me sense of what is being deposited and causing a ring. Obviously, the solvents dissolved something, and it accumulated at the edge of the drying zone to create a bit of a ring. This is not really that obvious in your images, but we take you at your word.
Here is my general criteria when dealing with surface issues before eventual varnishing: In general, and this is, of course an over simplification, if you are going to apply a significant varnish, meaning that it will substantially change the surface gloss, the final appearance will be very similar, but slightly less glossy, than the appearance of the same surface when flooded with odorless mineral spirits. Please do no sue me it you notice small differences but whetting up with a very low polarity solvent is one of the ways in which we as painting conservators ascertain how our painting conservation treatment will eventually look before we apply the final varnish.
As an aside, there are many possible materials in even “quality” paints that could be picked up and be mobile to create possible rings. Stabilizers and waxes could certainly be dissolved and then migrate to tide line air interfaces. Unbound fatty acids could do so as well. Organic materials are unruly beasts.
This does not sound like a major issue to me. Likely, you will be fine. Yes, the issue with sanding is more about making possibly toxic particles airborne. This can be dealt with by carefully wet sanding using a small amount of mineral spirits or even water if the painting can take that. The other possible problem with sanding is that if done carelessly or too rigorously, one could inadvertently remove too much surface and create a damaged texture or a too smooth spot. Sanding is even more problematic with glazed and indirectly painted imagery, but that is probably obvious to all.
