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Question asked 2021-04-10 16:28:12 ...
Most recent comment 2021-04-19 21:24:49
Oil Paint
Drying Oils
Art Conservation Topics
Grounds / Priming
Hello everyone- I am so happy to have found this resource and want to preemptively thank you for providing this information to people.
I work in oils but haven't had any traditional training (in undergrad I did graphic design) and everything I have learned was just through self trial and error and gleaning info from friends.
Recently I had an issue with the lightfastness of a color and through that experience learned about lightfastness which is easy enough to fix (I replaced tubes of paint) ---but it set off my anxiety brain. I wondered what else I may not know about (and the issue with learning by trial and error is what if the issue doesn't show up for years!? I used that color with horrible lightfastness for two years in a few paintings because the issue didn't show up until now.)
So I have embarked on a journey of asking very technically-minded painters their opinions on every part of my practice and by researching on sites like this one.
My painting process is luckily very simple which I hope will save me from huge structural issues. I actually have always just painted from the tube and have added no solvents or mediums. Much of the time a section of a painting will be done wet on wet in one layer but other times I will rework a section after it has dried. Since it's just the oil paint my understanding is I am painting only with fats and that should be structurally sound. The only times I've ever had cracking was when I really violated a thick over thin rule (like painting a relatively thin layer over a thicker color that was still tacky). In those cases the cracks showed up by the next day.
However- talking with people and stress-testing old canvases I have learned that I am not gessoing enough and that the acrylic gesso I was using is not the best quality it could be. I'm going to in the future move to using Golden's acrylic gesso and will do at least three to four layers.
I have found that my paintings often are underbound. A finger rubbing won't do anything but if you rub them with some pressure with a paper towel the towel will be very slightly stained.
I think going forward the better gesso (and maybe even trying oil gesso) as well as adding a tiny bit more linseed oil to my paints will help fix this issue. But I am curious about the paintings I have from the past decade of painting. This isn't an issue that has come up as the paintings aren't rubbed or placed under stress-test situations in the real world. I've sold many paintings over the years so I do have a concern about their archival-ness.
Very long-winded but I suppose the question I am most curious about is whether there is a spectrum of unbounded-ness? If something is "slightly" unbound and kept in normal safe conditions will it be safe for at least our lifespan? (Obviously this is probably a case-by-case answer but any knowledge shared would be very appreciated)
Thank you so much for your time and insight.
-Tony
PS also am curious about fingernail tests. I've read that a way to make sure a layer is dry enough to paint over is to scratch it with your nail and if it comes off powdery and not gunky it's ready. But other people asking questions on here about the structural integrity of their work have said that their pieces aren't effected by a fingernail test as a way of proving they are sound. I may be going too intensely with my stress-tests but yes if I'm sitting there scratching with pressure over and over on a spot I can start to damage the paint.
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Moderator Answer
(mkinsey)
If your priming is inadequate and the support has taken up a significant portion of the vehicle, it's possible the paint could be underbound, but I'm not sure you can conclude that just because you were able to lift some color by rubbing vigorously with a dry paper towel. Paper towels can abrade delicate surfaces, and it may be that friction alone was enough to remove some material that was present in a textured finish from brush strokes. Of course, I'm not a conservation professional, and I am just guessing by your description.
It's certainly a good idea to upgrade your materials and improve your priming technique, especially if you have been worrying about it. If you were making a good faith effort to do a good job in your past work, then in my opinion, there's no sense wasting time feeling guilty or worrying excessively. If a collector does approach you with a problem, find a professional resolution that preserves your reputation and pride. That's really all any of us can do.
The fingernail test I'm familiar with is usually just to see if it's possible to indent a paint film, to see if it is firm throughout. Normally, it's not a good idea to try to scratch off paint, unless you really suspect paint failure. Hope this helps!
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Moderator Answer
(brian baade)
Thanks Matthew,
I am taking a week off of the internet, except for the following response, to help celebrate my daughter's 4th birthday. Please forgive my lack of responses to posts.
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Moderator Answer
(brian baade)
Better materials are generally a pretty good way of avoiding
pitfalls. There are a ton of crappy acrylic dispersion grounds out there.
Gravitate to a product made by a company that has pride in their quality of
materials.
You should also make sure that your oil paints are of artists
quality (this used to be something that you could count on if it is written on
the label, no longer, there is a plethora of horrible art materials sold as “artists
quality” or even “professional quality”.
Paints make with superfluous extenders like aluminum
stearate (well beyond the legitimate oil stabilization proportion) will create
paint films that are less stable and less coherent than paints made with less “stabilizers”.
Aluminum stearate by itself in oil makes a rather solvent soluble and “soft”
film.
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Moderator Answer
(mkinsey)
I would certainly agree with Brian's position that starting with better materials is an easy way to prevent paint failure. Learning some benchmarking techniques can help make head-to-head comparisons of the same color between brands, without the distraction of brand appeal, romance and sentimentality. Many of these tests start with the same color (same pigment composition) from 2 sources, compared side by side in tests for performance metrics like coverage, mass tone, tint strength, and undertone. Again, I don't think it's productive or necessary to do a lot of in-depth second-guessing about older works, but if there are still some colors in your kit that aren't giving you the desired results, it just makes sense, as Brian points out, to upgrade them to a better brand.
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Moderator Answer
(brian baade)
I believe that we have covered this to the degree that is
possible (long distance). Beyond that, I am not sure how we could come up with
a subjective test based on a very subjective understanding of how much pressure
and how much abrasiveness (given the disparate nature of different paper
towels) use to determine appropriate binding. What we have in our archive is
about the best that there is. Please search the posts. Natural Pigments’ Facebook
group may have additional info, but George is great at posting all essential
info here. We are, therefore, probably at parity. Scientific studies can be incredible
rigorous, but because of things like
the above, it is extremely important to not compare apples to oranges.
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