Editor’s Note:
Added April 26, 2022
For some time, our recommendation for artists using oils over acrylic has been to work over harder, matte acrylic surfaces and avoid working on softer gels and gloss products. Our intention was to optimize the level of adhesion that would be achieved on a toothier surface as well as avoid the potential for future cracking as the oil paints become more brittle. While we have not seen adhesion problems of oils on any type of acrylic, recent testing has shown the potential for cracking in certain instances and conditions when applying artist oils over all of the many brands of glossy acrylics we have tested. While we have not received notice from artists of this phenomenon, we are able to repeat this specific type of cracking in our Lab.
Please visit https://justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/ for an overview of our testing, results and updated recommendations for applying oil colors over acrylics.
Acrylic Underpainting
Acrylics under oil is nothing new. For half a century artists have confidently used acrylic gesso to prepare their raw canvas and panels for oil painting. So why not use a couple additional layers of acrylic to establish your design or build up texture? Acrylics have a wide range of consistencies and can be used as a ground, to tone a surface or make a grisaille underpainting. Unlike oil paints, that have variable dry times based on the pigment, the entire palette of acrylic colors dry at the same rate and are suitable for use in an underpainting. For those who might be concerned about the structural stability of oils over acrylic, for 30+ years we have been testing oil paint over water-based acrylics and have never seen any issues with adhesion or incompatibility. For an in depth look at this topic, see Using Oils with Acrylics. Keep in mind, that oils can be used over acrylics, but acrylics are not compatible over oil paints. Additionally, here are a few things to consider when using oils over acrylics:
Protect natural fiber substrates from oil penetration with at least 3 coats of acrylic gesso or 2 coats of acrylic medium. It is important to block oil from soaking into canvas, linen and paper because it can prematurely deteriorate the natural fibers. Examples of acrylic mediums to use for this purpose are GAC 100, Fluid Matte Medium or Matte Medium to name a few. While wood substrates are not damaged by oil penetration, sizing them will reduce their absorbency and provide an additional barrier between the wood and the painted layers.
Allow acrylic layers to dry fully before painting on top with oils. Even thin layers of acrylic can take up to 3 days to fully dry. We recommend waiting this amount of time after your final layer of acrylic before beginning your oil painting, and even longer if the layers are thickly applied. This also includes Acrylic Gesso or acrylic sizing.
Refrain from using soft or spongy acrylics as a ground or in an underpainting. Acrylics stay flexible indefinitely, where oils become increasingly brittle over the decades. A soft and spongy acrylic underpainting, especially if applied with any thickness, may put oil paint layers at risk of cracking if the surface is ever flexed. GOLDEN Light Molding Paste and Crackle Paste are examples of soft and spongy materials to avoid for this purpose.
Stay away from sharp peaks and textures. This relates to the above statement. Even gels and pastes that become quite rigid when dry, can soften with increased temperatures and become flexible if applied in dollops, pointy mounds or ridges. Again, this may not be a concern for many years, but ultimately sharp textures could flex and compromise the oil paint layers applied over top. Barring strong peaks and ridges, it may actually benefit to build texture with acrylics instead of oil paint because oils can take a very long time to fully cure when applied thickly and in some extreme cases, never fully dry.
Be aware when using highly absorbent acrylics under oil paints. Some acrylics are designed to be highly absorbent, like the GOLDEN Absorbent Ground. These materials can draw an excess of oil out of the paints applied on top, potentially leaving those layers under bound. Some oil penetration into the underlying layers is beneficial for good adhesion, but having too much oil drawn out of your paint layers can leave oil paints matte and friable with the potential for cracking or flaking. Apply washes of thinned acrylic or thinned oil colors to help reduce absorbency to make these types of surfaces acceptable for use with oil paints.
More layers = Increased stiffness. Increased stiffness provides a stable base for oil layers that will become rigid over time. This is especially important when working on flexible supports. Several acrylic layers (4+) should provide increased stiffness depending on the product and the thickness of the application.
Gloss or Matte? We have seen excellent adhesion over both, but typically matte surfaces provide more tooth for improved adhesion in any system, oils or acrylics. When possible, use matte acrylics or apply a thin layer of Fluid Matte Medium over a glossy acrylic underpainting to provide additional tooth.
Watercolor Underpainting
Although watercolor under oil is not a widely used technique today, it is surprisingly effective and was well known, at least in the 19th century, among British painters (Carlyle, 2001). We found that regardless of whether the watercolor was soaked into the ground or dried over a glossy acrylic surface, that oil paint, medium and/or odorless mineral spirits could be applied on top without reactivating the watercolor. We tested QoR bound in Aquazol, as well as competitor brands made with gum arabic with the same positive results. We did not test watercolor over oil grounds, but historically it was practiced after the ground was deglossed and then properly cleaned to facilitate better wetting of the surface. Artists also used to mix ox gall into their watercolor to keep their washes from beading up. A benefit of watercolor is they can be reworked even after they dry, allowing artists to perfect an underpainting or wipe back to a bright white ground to establish the lighter areas of a composition. Unlike acrylics, watercolors do not require several days to completely dry and coalesce. They should be ready to paint over after they are fully dry to the touch. Here are a couple things to consider when using this technique:
The substrate still needs to be sized to protect from oil penetration. The exception being oil paper, which is already sized and prepared for oil paints. The watercolor layers do not count as sizing. Instead, prepare the substrate as if oils will be applied directly. In most cases, using watercolor in this way essentially amounts to making a mixed media piece with acrylics, watercolor and oils. It may benefit the watercolor application if the final layer of acrylic sizing or the acrylic ground is slightly absorbent.
Do not apply the watercolor thickly. The oil needs to be able to soak through the watercolor and bind to the substrate or ground. Thick applications could interfere with this important aspect of proper adhesion.
Do not isolate the watercolor from the oil paints with MSA or Archival Varnish. We have written many articles about the benefit of varnishing watercolors so they can be displayed without glass. This is great, but should not be used for this application because oil paints are not compatible over top of MSA or Archival Varnish. For more information see Why Oil Painting Over MSA or Archival Varnish Is Not Recommended.
Options for protecting exposed watercolor. Artists in the past optionally isolated their watercolor with a dilute natural resin varnish or very thin layer of light colored drying oil applied with a sponge. Although this might benefit an area of watercolor that is left exposed, it does not seem necessary to improve compatibility between the watercolor and the oil layers. This may have served a dual purpose of reducing absorbency of the ground and locking down the water sensitive paint layer. With this historical approach in mind, it may benefit to fully cover the watercolor underpainting with oils paints or at least glaze over all exposed watercolor to protect it from the potential of lifting. Alternatively, if after the oil painting is finished and there is still watercolor exposed, it can be varnished after the appropriate waiting period. We recommend allowing oils to cure for 6 months to a year before varnishing.
Acrylic and watercolor underpainting and toning techniques can speed up the initial stages of the oil painting process. They are also great ways to remove solvents from the studio and still get thin, washy, saturated applications to work on top of. We recommend testing to see how this can benefit your studio practice and maybe even change the way you work all together! We hope these considerations will help you confidently explore this combination of materials in your future paintings. Please let us know how it goes! If you have any questions or comments, please contact our Materials and Application Department at 800-959- 6543 or [email protected].
Additional resources:
Just Paint: Using Oils over Acrylics
Just Paint: Why Oil Painting Over MSA or Archival Varnish Is Not Recommended
Carlyle, Leslie, (2001) The Artists Assistant, Archetype Publications, London
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Wow, I had no idea one could paint over watercolors with oils! I’ll have to give this a try, it might open up a whole new range of possibilities!
Hello Joshua,
It is pretty great to have such a simple solution for solvent-free, fast drying underpainting. We hope it works out well for you. Let us know how it goes!
Take care,
Greg
Hi Greg!
Based on this info, would it be ok to use a watercolour pencil on a pre-primed canvas/ oil Paper? And then apply the oil paint over that?
I’d like to do an under-sketch, then a thinned (with solvent) layer of oil
Been round in circles looking at dozens of forums & advise on what is ok under oil!
Thanks!
Hi Vicki,
Thanks so much!
We did not test watercolor pencils for this article, so cannot recommend their use one way or the other. That said, it may be possible to sketch in watercolor pencil and then work over top with oils, but it may require some testing to do so with confidence. The only potential drawback would be if the pencils contain wax. Waxy materials can have an impact on adhesion. Oils might bead up over wax and not stick to that surface very well. The other potential issue with wax is that most waxes can be reactivated with solvents. For example, if you did an oil wash that contains solvent (even odorless mineral spirits) over a pencil that contains wax, it may smudge the drawing. This would also be the issue with oil-based or wax pencils. This could be tested by drawing out lines with all the colors you would use in an underdrawing, manipulate the line work as you normally would with water etc, let dry. After it is dries, paint over top with oil paints and washes made with solvents. if everything stays put and the washes do not bead up, then there is a good chance it should be fine. The next step of the test would be to let the oils dry for a week or more, then burnish a piece of masking tape to the surface over different areas of the test, especially where the underdrawing is at its thickest. Then tear the tape off the surface to see if the oil comes away from the watercolor drawing. If not, then it would indicate pretty good adhesion. If the oil peals off, then we would not recommend this combination of materials. This may sound complicated, but testing for your application can be fairly straight forward and a good way to learn more about your materials. If adhesion seems good, then you should be able to use this technique over preprimed canvas or on oil paper.
Here is an article about testing for adhesion in your studio: https://justpaint.org/will-it-stick-simple-adhesion-testing-in-your-studio/
Hope this helps!
Greg Watson
Thanks so much for consolidating all of the relevant technical information related to using oils over water-based underpainting in one, succinct place. Much appreciated!!
Hi Susan,
You are very welcome. Glad you found it helpful!
Greg
Thank you Greg! Very clear blog and succinct as well. I love reading your postings.
You are so welcome! Thanks for the comment!! 🙂
Great article with lots of information. You didn’t mention the advisability of acrylic on oil paint grounded canvas covered boards. These are available at reasonable cost, are very portable and mountable. They are advertised as non-adsorptive, and I wonder how that affects the acrylic adhesion?
Any advise is appreciated.
Alan
Hi Alan,
Appreciate it. Thanks for the question. We do not recommend this, as we have not seen consistently good adhesion with acrylics over oil paints or oil grounds. Although acrylics do seem to stick to dried oils in some cases, they can often be scratched or pealed from the surface. Even if there is apparent adhesion, we are not sure about long term stability of this combination. As mentioned in the article, watercolor might be a possible solution in this case. The surface should be slightly toothy so that the watercolor and subsequent oil paint layers have some grit to grab. We recommend testing. After the watercolors and oils have dried for several weeks, you can perform a down and dirty adhesion test as outlined in this article: https://justpaint.org/will-it-stick-simple-adhesion-testing-in-your-studio/
We hope this helps! Best wishes in the studio.
Greg
Greg and Golden Staff,
All the articles the Golden staff produces are so informative. Thank You!
Mark
Hi Mark,
Thank you! Glad you like JustPaint. Most of the articles are written by our Technical Support team. We are here to help if you ever have any application or product related questions. [email protected] or 800-959-6543.
Take care,
Greg
The article mentions oils degrading the fibers of the substrate should it be exposed directly, but I have spent a few years trying to locate any testing done in regards to this and have yet to find any. Is there a link to a test done that shows oil degradation of fabric or paper surfaces?
I am looking for just oil on the surface, not oil paint or anything like that because pigments in paint have been shown to cause degradation to surfaces when exposed to oxygen, temperature, and other natural environmental situations.
Hello,
Thank you very much for your comment. Here are a couple of links to papers on that topic. Both paper seem to be done by the same team, but they look at the issue from slightly different angles. They compare oil paintings / studies done on paper in museum collections with clear signs of oil penetration and degradation to lab controls made with a variety of papers soaked with linseed oil. Their results show cellulose fiber degradation through visual and structural analysis as well as by reading emissions of compounds that are created during degradation.
We hope these help. Let us know if we can do anything else for you.
Greg
Investigating the conservation problems of oil paintings on paper supports:https://www.academia.edu/17941194/Investigating_the_conservation_problems_of_the_oil_paintings_on_paper_supports
Oil paintings on paper support: Determination of condition criteria
via non destructive testing and microanalysis: https://www.academia.edu/24555915/Oil_paintings_on_paper_support_Determination_of_condition_criteria_via_non_destructive_testing_and_microanalysis
Good day/evening Mr. Greg.
I am also wondering if Golden has any current and/or future plans to make water-soluble version of your Williamsburg oil paint range and/or mediums to make them water-soluble (i.e. water-miscible safflower oil) in order to achieve watercolor-like effects and make clean-up easier.
Thanks.
Hello Clarence,
Thanks for the comment. We do not currently have any plans to make water-miscible oil paints or mediums that could modify our current line. For a short description about how to clean your brushes when using regular oil paints without the use of solvents, see this blog post from our Williamsburg site: http://www.williamsburgoils.com/blog/?p=103
Best wishes,
Greg
Thanks Greg! I’m hoping you will undertake a study on the use of conventional oils over alkyd underpainting?
Hello Alex,
Thanks for the good suggestion! It seems like this combination follows the slower drying over faster drying model, which is recommended. We would not expect to see issues with this unless the alkyd layers were exceedingly glossy, which could cause adhesion issues. If this is a technique you use, you may be able to perform a simple adhesion tests to assure the conventional oils are adhering well to the alkyds. We outline the procedure for a simple adhesion test in this article: https://justpaint.org/will-it-stick-simple-adhesion-testing-in-your-studio/
We recommend trying this on a sample or test piece. Please let us know if you see anything unexpected!
Thanks again,
Greg
I have been painting this way for almost 20 years. I’ve told a few people who thought less of me for the mere suggestion of using watercolor, acrylic and oils in the same painting.
Thank you for clarifying this method as not only possible but historically accurate.
Hi Irlynda,
You are welcome! It is great to hear you have had success with these combinations. Best wishes moving forward!
Greg
Thank you ♥️ for sharing this with us. I’m doing Irish scenes for a shop and this is really making progress easier.
Hi Jane,
You are very welcome! We are glad it has been helpful. Let us know how it turns out! It would be great to see some images if you feel like sharing!
Thanks and best wishes,
Greg Watson
[email protected]
Hi Greg, thanks for the very useful and detailed article.
I have one question – where you say:
‘Apply washes of thinned acrylic or thinned oil colors to help reduce absorbency to make these types of surfaces acceptable for use with oil paints.’
I would like to know whether you mean thinned with water, in the case of the acrylic, or thinned with some sort of acrylic medium. Would water thinned painted be too absorbent (say at 50%) to paint over in oil. What would be the maximum percentage of water you could dilute an acrylic underpainting for oil by?
If one were to use a very watery acrylic for underpainting,would it be ok to seal it with a coat of acrylic size before the oil layer?
Oops more than one question really – look forward to hearing from you.
Thanks
Alex
Hello Alex,
Thanks for your question(s). You should be able to dilute your acrylic paints, mediums or a combination of both with how ever much water you need to get the effect you are after. 50% water is a very safe dilution. There is no limit to how much acrylic medium you can add to your paints, as you are simply adding binder which will increase transparency but not weaken the paint in any way.
We have tested acrylics thinned 1 part paint to 1 part water all the way up to 1 part paint to 100 parts water. In all cases, we did not see any issues with adhesion, but only in the extreme dilutions did we see water sensitivity in some colors. This should not be an issue when working over top with oils. Here is a link to that testing: https://justpaint.org/how-much-water-can-you-safely-add-to-acrylic-paint/
Keep in mind, the more you dilute, the thinner the layer, and less binder there is to lock up absorbency. Very absorbent acrylic grounds may need several coats of highly diluted acrylic to reduce the absorbency. It may only take one coat of full strength or slightly thinned acrylic to achieve the same effect. If you wanted to apply an acrylic coat over your acrylic underpainting, a single layer of Fluid Matte Medium should do the trick. This also has the added benefit of providing tooth if the acrylics are at all glossy. Give an acrylic underpainting a couple days to dry before painting on top with oils.
feel free to call with any other questions – 800-959-6543.
Best Regards,
Greg
Very useful article, thank you.
I have a question, I’m wondering whether a watercolour painting on unprimed watercolour paper could have oils painted over it if the original watercolour painting were protected afterwards with a clear gesso or matte medium product? If I understood correctly all your examples are about watercolour/acrylic painting onto a prepared background but presumably it wouldn’t matter if the oil barrier was after the watercolour stage?
Thanks in advance!
Luci
Hello Luci,
Glad it was helpful! The only challenge would be applying the water-based acrylic without smudging the watercolor. That said, if you can get a couple layers of acrylic onto the watercolor with minimal smudging, you should be good to paint on top with oils. If you use an airbrush, then a couple thin coats of High Flow Medium should start to reduce sensitivity of the watercolor and then you could apply a couple brush layers.
Let us know if you want to discuss this possibility further. You can email [email protected] or call 800-959-6543.
Best,
Greg Watson
What about if the underpainting is in acryla gouache layer do you need a clear medium or anything before applying the oils? I read that another artist using this method applied liquin between the gouache acryla before adding the oil layer, but I’m not sure if the liquin is really necessary. Great article! Thanks for all the technical information.
Hello Courtney,
Thanks for your comment. We have not tested oils over Acryla Gouache, but imagine it should be fine to paint directly onto that surface. It likely has nice tooth and absorbency. The only concern would be if it is too absorbent. If that is the case, a thin wash of oil paint or a thin layer of acrylic Fluid Matte Medium should lock up some of the absorbency before applying full bodies oil paints. Adding a layer of Liquin might only serve to complicate the layering. And, it is not likely a required step, other than it would serve to reduce absorbency of the surface. If a lower absorbency surface is desired, then painting the underpainting with regular acrylics with a satin or semi-gloss sheen should help.
Best,
Greg
Hello,
Can you tell me if I will have any adhesion issues or other problems if I use Caran D’Ache supracolor II watersoluble pencils
for an under painting sketch for my oil painting? I am using a canvas coated with acrylic gesso.
Thank you for your advice,
Cynthia Pedrazzini
Hello Cynthia,
Thanks for your comment. We have not tested oil over Caran D’Ache Supracolor II watersoluble pencils. Adhesion could be an issue if there is wax in those pencils. We have seen poor adhesion over oil pastels and cold wax/oil color mixtures. If the pencils are not applied too heavily and there is still exposed gesso, then it might be fine. The other drawback of wax content would be that some waxes are soluble in odorless mineral spirits and most in turpentine or full strength mineral spirits. If you use solvents in the initial layers of your oil painting, it might smudge the crayons. Either way, we recommend testing to see how it works before using on a final artwork. Here is an article on adheshion testing: https://justpaint.org/will-it-stick-simple-adhesion-testing-in-your-studio/
Take care,
Greg
Hi Greg,
Could I ask if this post has been edited recently? I thought that I understood that you originally mentioned Golden’s Pastel Ground as a suitable preparation for oil painting on paper. I purchased some and have found it an excellent surface for watercolour, however I now on re-reading the article find that if I wanted subsequently to paint the paper with oils, I should have first sized my watercolour paper before applying the Pastel Ground. If I was to have used Pastel Ground alone and then watercolour, then oil, will that mean the artwork will be non-archival and will deteriorate? Thank you!
Hello Dolores,
No we did not edit this article. The Pastel Ground should be a fine surface for your watercolor, then oil, but like Gesso it is rather absorbent, so there needs to be enough layers to block oil penetration into the paper. It takes 3 layers of Gesso to block oil. Pastel Ground could use the same number. If you do not want significant build on the surface, then you could apply an initial layer or two of Fluid Matte Medium or a similar product and then a single layer of Pastel Ground. The acrylic products can be layered once touch dry, so the preparation can go pretty quick.
Hope this helps! Thanks for your comment.
Greg
Hi there,I’m usuing terra skin paper.Painting with clothing dye(rit)
Can I paint over this with acrylic,and or water mixable oils?
The dye has alcohol sprayed over it.or denatured.alcohol.
thanks in advance Len
Hello Len,
We do not know if the fabric dyes will be reactivated by the acrylic or oils. You will have to test your application to see what happens. Please keep in mind, that Terra Skin is not meant to be a permanent. It is a biodegradable material that will break down with moisture and UV light. here is a link to an article that discusses calcium carbonate papers, similar to the Terra Skin: https://justpaint.org/acrylics-on-non-porous-substrates/
We hope the testing goes well. Please contact [email protected] with any additional questions.
Best,
Greg
Hello Greg, thank you very much for this article. My question is: what final varnish can be used when painting acrylic under oil? Taking into account that I leave the acrylic layer partly visible.
Greetings from Italy,
Davide
Hello Davide,
You are welcome and thanks for your question. You should be able to use our MSA Varnish over both acrylics and oils. If the acrylic is still separate enough from the oil layers, you might choose to apply a glossy acrylic isolation coat over JUST the acrylic sections. The isolation coat should not be applied onto the oils. Once the isolation coat has dried for several days and the oils have cure for many month, the diluted MSA can be applied. MSA comes in Gloss, Satin or Matte and needs to be diluted with MSA Solvent before use – 3 varnish to 1 solvent for brush application. We also have a spray version of MSA called Archival Varnish. Please contact us for more info on varnishing by emailing [email protected]
Here is a resource on varnishing products and techniques: https://www.goldenpaints.com/technicalinfo/technicalinfo_varnishresources
Here is a video about Isolation Coat: https://www.goldenpaints.com/videos/isolation-coat-application-for-small-paintings
Take care,
Greg
Hello! I hope you can help answer my question as I have been searching and not found any reliable answers.
In my pastel paintings, I often do underpaintings on sanded paper using Pan Pastels or soft pastels washed in with 70% isopropyl alcohol. It dries very quickly, ready for further pastel layering.
Currently I am learning to work with water mixable oils on acrylic-gessoed stretched canvas and canvas panels.
Can I still use a pastel/alcohol underpainting on these supports before applying oil? I suppose I could also wash in the pastel with water, but this takes longer to dry.
Just wondering if there would be 1) problems with the alcohol affecting the gessoed surface, and 2) problems with oil adhering to the dried underpainting surface, and if so, wonder if I would need to seal the underpainting with something to increase adhesion and decrease absorbency before applying oil paint?
Sorry, new to all of this!! Thanks for any and all help.
Sincerely,
Rhonda
Hello Rhonda,
Thanks for your question. This is not something we have tested exactly, but it is likely the powdery pigment of the pastel would get mixed into the oil paint applied on top. Also, dusty layers on the surface can act like a resist and keep the oil or acrylic from adhering to the surface of the substrate. The watercolor is bound enough that it holds tight to the surface and is not reactivated with additional oil layers, and is usually applied thin enough that the oil can seep through and connect with the surface. You may be able to mix your pastels into some acrylic medium, like Matte Medium, and use that as a colored wash on the gessoed surface. Then after that is dry for a couple days, the oils should be able to be applied over top. Mixing the pastels with acrylic will likely saturate the color and make them appear darker. This is a bit of an experimental layering technique. We recommend testing on some sample pieces to see if it works how you would expect.
Hope that helps. Best wishes!
Greg
If I underpaint with acrylic, then water soluble oils on top but some areas still open to the acrylic, what do I use to varnish it? Thank you,
Jean
Hello Jean, thank you for the question. If you wanted to varnish the whole piece at once, you would want to use something like our MSA Varnish, but we recommend waiting 6 months to a year so the oil paints have a chance to cure. You could try and use something like Gamvar, where they recommend a much shorter cure time before applying varnish. We recommend testing if possible as we have seen variable results on acrylics of different thicknesses when using Gamvar. Let us know if you have additional questions! [email protected]