To oil out or not?

Hello, all! I´ve been scratching my head lately on the importance of oiling out to continue working on a dried painting. I think it´s a cool technique, but often I find that it´s very easy to add a lot of oil(even when trying to remove the eccess) and end up with a very slick or glossy surface. I find that besides having some colors that would have sanked in, it´s much better and simpler to just paint over the dried painting without adding any couch. What are your thoughts and experience on this. Is oiling out really necessary in a multi layer painting?


Thank you for this excellent question Jose. As with most aspects of an activity and complex as painting–there is no fast and easy, global answer. Whether or not “oiling out” is the right move in a painting process depends on quite a number of variables.

First I should say that I find far too many artists mindlessly include steps or stages in their process because someone else did or they have been told to. They have no real grasp of how certain factor, action, or particular material is affecting the overall dynamics of all variables involved. I urge all of my students to understand WHY they are including some variable before it is deployed. As such I am very glad to see questions like this.

As to sinking/oiling: One very peculiar behavior of oil paint that most painters are familiar with is the change in appearance that seems to take place when a paint film is curing. The paint may appear to lighten significantly, resulting in a chalky surface–or become blotchy with some areas appearing more matte than others. This is often far more evident in darker colors. This perceived change is due to the oil in the paint being drawn in to the absorbent surface that you are painting on. This effect is almost always eradicated when the painting is varnished so do not be alarmed if a drying painting begins to appear this way. However, when sinking occurs on a painting that is still in progress, certain steps may need to be taken to ensure it does not interfere with your process.

So how might sinking interfere with an ongoing painting process? Well, one way emerges from the perceived change in the paint value/color relationships. Let’s say that you have established a strong collection of value/color relationships that you feel communicate your subject successfully. Let’s also assume that the level of refinement that you seek will require the application of additional paint layers. The issue that will arise is that your judgements from here on out will most likely be based on the current (sunken) appearance of the work. The change in appearance due to sinking does not reflect how the painting will look when it is varnished—which may result in significant errors in judgement and adverse results.

For example, if we look at this Gradation Pattern exercise from the Language of Painting we can see how the painting looks wet versus with sinking during oxidizing (drying). If we match colors/values based on the “sunken” appearance, a later applied varnish (or other restoring agent) will indeed yield a significant disparity.

We contend with this issue as by “oiling out” only those areas necessary. Our process for this is often far more conservative than most. Only the area to receive paint and immediate adjacent regions are oiled out so as to maximize effective color and value judgement. Nothing more—

Here is an excerpt from the Language of Painting that touches on Sinking, Oiling out, and Sanding:

Now Jose, I agree with you 100000%. I HATE trying to paint into a slippery layer of oil—so again, I add JUST ENOUGH to activate a color/value. Again—nothing more.

Some however do like to maximize the fluidity or flow of paint so they add the “couche” (that you mention) before working on a dry painting. For those who haven’t come across this term before, “couche” is a French term for “layer,” and in the context of painting–a couche is a thin layer of oil that you spread over the entire work or a region that you are about to work on. The oil may significantly increase the “flow” of the paint. A couche will also add the benefit of restoring the initial appearance of sunken colors—but as the description suggests–it tends to be a far more cavalier or liberal application of oil. For me, the process of oiling out is an extremely conservative, localized couche.

I hope that this explanation is helpful and will allow you to make the right decision for yourself.

Additionally, Natural Pigments founder George O’Hanlon has made available some interesting material options that may lead to the avoiding of “sinking” altogether. If you would like more information regarding George’s materials I recommend research into some of their products here:

Happy Painting!


Forgive me if You mentioned this but could this sanding process be avoided with certain colors for safety reasons. I just worry about paint powder in the air that could be inhaled. I am dumb enough as is and I couldn’t imagine that would help.

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Thank you so much, Anthony!! I appreciate all your kind explanation…you have helped me a lot clearing my doubts. I agree with what you´re saying, oiling out or working into a couche should be used if its absolutely necessary not imitate so and so artists. If one is not careful is very easy to add too much oil and have a very glossy slippery surface. I have had one experience with a painting that whatever I was doing to darken a color…it seemed that anytime that it dried it always seemed to remain the same value as I had it before…in that case it was very important for me to oil out the painting…and as you have kindly mentioned that could have been of me not using the right medium(too much solvent too little oil). In another occasion I made the mistake of oiling out only the cast shadow area of the subject on the wall…when I oiled it out it already look dark and made it even darker when I finished painting it. I would love to fix that, but I might have already added too much oil when I oiled it out that it might not be a good idea.

Here´s a piece where I had to sweat working with a slippery surface after oiling it out:


LoL! I wouldn’t imagine that a truly “dumb” person would bring up such an intelligent concern. It is absolutely true that any airborne particulates can pose a threat to our respiratory system. I would not recommend any serious sanding of any paint film or ground without adequate ventilation and protection. Much of this is actually covered in previous LoP chapters (from where this clip is taken).

The sanding mentioned here though is extremely minimal. If there are significant airbone particulates tesulting from this then you are probably doing this far too aggressively. With that said, as you suspect, care should ALWAYS be taken to remove exposure to any possible airborne contaminants or irritants.

A great point Mark!

Thank you—


A wonderful work Jose! (That battery is fantastic!) And yes, all of the issues that you mention have come up for me in the past as well—and I was doing just what I warned against—adding steps and materials needlessly without adequately assessing my process to see what was actually necessary (and understanding why.)

I am glad that this was helpful and look forward to seeing more of your work.

Happy Painting!

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In the picture of the sunken sphere exercise, what is does the image at 7:30 represent (i.e. the image with no label)? It looks pretty much the same as the sunken image.

CD image C



Ahhh–Great catch John. The image is supposed to be the sunken image still but with an indication of the region that one would be matching (which one might only later find out is not a true representation of the paint film appearance.)


Sorry it has taken me so long to read this. I always oil out a dried painting. I use no-solvent gel medium so I can rub it on with my fingers to apply it thinly, but here’s the step that works best: wipe all the excess off with a clean lint-free cloth. The layer becomes very, very thin and the surface will not be slippery. Paint will apply easily and not be patchy looking and the color will be matched. Works for me!!!


Just seeing this via mailbag…love it. sinking has driven me mad and I am guilty of oiling out with a lean medium. Question: am I understanding that the whole painting or sunken parts can be sanded with 800 grit. Some do a wet sanding, which is after the couch layer. Did you ever try this?

Hmmmm—I haven’t heard of that one Nanci. I only sand a painting if there is a topographical issue that may lead to value/color miscommunication. I never heard of sanding as a way to deal with sinking.

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