This was fascinating - normally, anything technical tends to cause my eyes to glaze over, but I could have watched another hour of this, quite easily. And that's because you explain the things I really want to know, without digressing into - well - waffle. It's also good - very good! - to find a company that really invests time and money into research: I wish some others did as much, rather than churn out the same old products without showing any curiosity about their performance: the interest of some of them seems to lie entirely in the balance sheet. I should love to see more of these: I do subscribe to your newsletter and updates.
I watched this video just in time before deciding to make more stretched canvas, pondering if I should stick with traditional rsg followed by oil ground or not. The whole "oil over acrylic is ok" is too sketchy for me now. I have experienced cracking on pre prepared oil ground linen canvas glued on synthetic panels and it is pretty awful to see happen. I can only guess the linen was sized with an acrylic layer underneath with an oil ground on top. I shudder at the thought of what has happened to those paintings I have sold before the cracking appeared. So, my conclusion is to stick with what I know works and not venture into any acrylic application under oils. Rsg works and no problems unless you put your painting in extreme atmosphere conditions. All I want is for it to not crack while I am still around due to misuse of materials and buying into companies that push products to buy something unproven. Thanks for doing this video. Now I will be busy buying more raw canvas and doing it all from scratch this summer.
Thanks for your comment. We understand your concerns and would not try to sway you one way or the other. As you mentioned, RSG is time tested and the expectations around the product is well understood. Hopefully the research will continue around modern materials used in conjunction with oils and we will have a better understanding how to safely move forward without risk of unexpected issues. We hope to do our part in that effort!
One way to determine if this is chemical or mechanical is to perform a test on GAC100 or gloss acrylic, but sanded with fine sandpaper to knock down all the gloss. Paint thinned with turpentine is very fluid and has very low surface tension, there isn't much holding it down if the primer lacks tooth or porosity. I've seen something similar when trying to paint urethane varnish over glossy acrylic. It looks fine at first painting, but as it dries the varnish coat will wrinkle dramatically. This is because the urethane varnish is shrinking and can't hold onto the glossy acrylic, the dissimilar films are not bonding, and it allows the urethane to flow however it wants to as it dries.
I watched this video to learn about a problem that I have not encountered: cracking of oil paint layers applied over acrylic base layers. I was pretty interested since acrylic base layers are a key part of my process for building a surface that doesn’t take weeks. The video made me reflect on my own experimentation over the years and what might be behind the ease and seeming (so far!) success of my current process. I will quickly outline it here in case there is scope for further learning through further feedback from other sets of grey cells. I am currently sticking linen onto pre-sanded ACM using waterproof exterior quality builder’s PVA. I have been a bit surprised that PVA seems to stick better than a couple of glues specifically formulated for sticking to metal. I dry the canvas for a couple of days and then rotary sand (240 grit). Then a couple of layers of super matte chalk paint of preferred colour(s). Sand with 400 grit. Then artist’s oil of preferred TRANSPARENT colours mixed with Penetrol for oil layers adhesion plus Liquin alkyd medium for flexibility. Sand again. Repeat oil layers and sanding for complexity, lustre and mystery. To the touch, this surface is like canvas sex - smoother than silk. The multiple transparent oil layers mean you can see right through to the pattern of the linen in-filled by the chalk paint. Then the piece is ready for adding subject content. Would love to learn of others’ experience.
Thank you for sharing your layering. The combination of commercial building materials with art materials is interesting. We haven’t tested blending oil paints with Penetrol. Certainly, an interesting experiment. Glad to hear this works so well for you.
its happens to me with Lukas 1862 oils, only with ultramarine blue and cobalt blue, i dont use acrilic underpainting, only guesso (white guesso), excellent video BTW, other thing one thing that i discovered to prevent crackling in my colors is to watch how they dry, and if the start to lock mate to fast, then they problally will crack so i add a thin layer, (like a glaze) of pure linsed oil to them and thats help a lot
Thank you for the feedback! We have not spoken with too many people who have experienced this issue. So, we appreciate you sharing. Very interesting observation about the surface turning matte. We are working with conservators who have advanced tooling to determine the exact causes of matting on oil surfaces when used over acrylics, and if that is a feature of this issue. We are hoping to map out the sequence of events from oil application to when the cracking happens, and to understand the specifics about why it happens with certain products over others etc. We hope to provide additional understandings at some point during the next year through Just Paint.org.
Thank you Golden paints, you are so professional. Even if people cannot buy Golden acrylics because they are too expensive in Europe. I was going to start with oil painting over acrylics ! I need time understanding you. If you could, explain in one sentence how to paint oils over acrylics without cracking ? As I understand it: 1. No oil over gloss mediums. or 2. Gesso, applied, min. 3x of clear Gesso. or 3. Mix 10% stand oil to my oil paint, the first layer, probably 5% is enough. or 4. Further oil paint layers need to be fatter.
Hello. Based on our research, those points taken together should provide a successful layering of oils over acrylic. Yes, avoid glossy mediums. White Gesso seems to be more stable than clear gesso, but even the products we have tested labeled as “Clear Gesso” did relatively well with a couple exception. IF the oil layers over top of the Clear Gesso had been modified with oil or oil medium, then it would have likely been totally successful. We just tested lean colors. The oil layers after the first can have the same amount or more medium added. If you have additional questions, please email GWatson@goldenpaints.com and Greg (from the video) will assist you.
I’ve been following the past recommendation to use gloss acrylic as my first coat on the canvas as a size and barrier to prevent SID (substrate induced discoloration) and against oil damage to the canvas. But I also added many subsequent layers including ‘matte high solid gel’ before finally painting on top with oils and I haven’t seen any cracking yet. Are you recommending avoiding gloss acrylic as a size/barrier even with subsequent layers?
I have just sealed two large cradled birch panels with gac 100. If i gesso over this will i still be able to paint with oils over this ? What im confused on is are you painting diectly over gac 100 as if its a primer ?? Is it ok to use gac 100 as a sealer then acrylic gesso thrn oil paint ??
When priming an HDF panel with 3 coats of gesso prior to oil painting, should one also paint all sides & back of the panel with gesso in order to mitigate the chances of the panel warping, or is this not necessary? Thanks in advance! 🙏
It can be helpful to cover all the sides of the panel to help equalize tension. You can simply use Gesso, or for a cost savings approach, you can try house paint, house primer or shellac on the sides and back.
Im actually c9bfused can i use gac100 as a size or not ? I have already used it on goldens own recomendation !i was just gling to gesso these panels. Please advise promptly. I shoukdnt have to worry about this since gac100 was sold to me as a great sizing product.
Hi, Shelly. We hope this answers both of your questions on this video. We have always advised oil painters to avoid working directly over any glossy acrylic paint or medium layer. When we investigated why we were getting hairline cracks in the first layer of oil paint, we were able to repeat the issue whenever there was pure oil paint over glossy acrylic products. Therefore, we wanted to bring the test results out into the public eye so that artists were made aware of our discover which also allowed us to get the painting conservation community involved to learn the cause. In this recorded live demo, around the 23-minute mark, you’ll see Greg address the use of acrylics under oil paints, with the addition of various oil painting mediums. The added oil does a great job to stave off the potential for cracking. The greatest concern in the testing was oil paint direct from the paint tube, so if that can be avoided while you work, you should still be able to use these previously prepared panels. The Just Paint article (linked in the video description) discusses this in greater detail. But if you only paint with pure oil paints and do not add any medium or solvent in your first layers, then three coats of gesso without sizing is the best approach. Our Materials & Applications Specialists would be happy to chat with you more about this. You can reach them directly at help@goldenpaints.com
@@GoldenPaints You really did not answer her question, can you use GAC 100 as the hardboard sealant with 3 layers of acrylic gesso and be able to paint oil paint on the acrylic gesso without worry of cracking due to the GAC 100 ? In otherwards, Is the GAC 100 a suitable and safe sealant over the panels followed by acrylic gesso for oil or acrylic painting without the cracking ? Telling me to just watch the video again is no help as he is confusing
Late to this conversation, but I'm curious if clear gesso will require less coats over a mixed media work given is has so much more tooth than regular gesso. I also heard that you still need a good lean but clear oil ground over the absorbent gesso to keep the oil paint and pigments from being sucked into the gesso over time. Would love some clarity :)
Thank you for your question. We did include some clear gesso and other matte surfaces in our testing, and amending the oil paint with the addition of medium when painting on these surfaces can be good practice. More information may be found in our Just Paint article "Revisiting Oils Over Acrylic" (and its comments) which may be found here: justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/. We have not seen oil being absorbed by our acrylic gesso over time, however we have seen very absorbent surfaces wick oil from oil paint as the oil paint dries. You might also find our Just Paint article "Differentiating Between Acrylic Gesso and Williamsburg Oil Ground" to be of interest justpaint.org/differentiating-between-acrylic-gesso-and-williamsburg-oil-ground/
Thanks for your comment! The curing time is similar between matte and gloss acrylic products. We tested older acrylic surfaces that had been dry for years with similar result against the same product that were only dry for a week. It likely has more to do with the type and quantity of matting solids in the matte mediums and gels that contribute structure to the acrylic film.
Airbrush Medium is closer to GAC 100 in viscosity, but is not like either of these mediums in behavior. Since Airbrush Medium was formulated to help Fluid Acrylics be sprayable, it is loaded with so many retarding agents it should not be used by itself. Always mix Airbrush Medium with fast drying acrylic products or the application might not dry. We also do not recommend any of these three glossy products for application under oil paint. Please see these related resources for more information: GOLDEN Airbrush Medium application sheet: goldenartistcolors.com/resources/airbrush-medium Just Paint article Revisiting Oils over Acrylics: justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/
Thank you so much for this study report! It was insightful for me as an artist and very intriguing for me as a scientist. I am wondering now if there are any job opportunities for a geologist at your research division...
On our website we have a job listing section. You can always take a look and see what we have available! workforcenow.adp.com/mascsr/default/mdf/recruitment/recruitment.html?cid=1ad5f229-7e85-4993-8c86-672e31079f3b&ccId=19000101_000001&type=MP&lang=en_US
So if more matte means less cracks, then I wonder if acryla gouache would work as a base? Acryla gouache is really just very very matte acrylic that looks like gouache after all.
We have not tested oils over Acryla Gouache. We did find that when oil paint is applied over our matte SoFlat Acrylics, the acrylic can pull an oil halo out from the oil paint. This might not be an issue if the entire SoFlat surface is covered with oil paint. For more information on oils over SoFlat, see the SoFlat Application Sheet: goldenhub.goldenpaints.com/storage/uploads/SoFlat_Product_Information_02.pdf
11:45 is that oil paint or acrylic color paint also the next one I cant tell if you are spreading oil white paint over GAC 100 or acrylic paint over GAC 100 that is cracking, I was going to use GAC 100 under acrylic gesso for hardbard, but not sure what to do now. Also the question of oil paint over acrylic paint wasn't answered that made sense, so cant you or can you??? I am more confused now. Any way you can repeat this video with more information on exactly what you are doing, with more on what you are painting with etc. Remember we are not researchers out here, just normal people that need a more complete description, it seems scattered more for a researcher to researcher.
What Greg is showing at 11:45 is a laminated card with a wide horizontal strip of GAC 100 applied on the card. The GAC 100 is so clear that it’s not visible. Then the vertical reds and purples are oil paints that were applied to show the differences in cracking that some oil paints have. To prepare your hardboard panels, we’d recommend to apply the acrylic Gesso directly to the panel, or size with a coat or two of PVA size. There are many different types of PVA glues and sizes available. We’d recommend getting a PVA that is intended for art making.
If painting with oils over a clear gesso, which is similar to our Fluid Matte Medium, we advise adding a little oil or medium to your paint. You may find this article to be a helpful resource justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/ Feel free to reach out to our team of Materials Specialists with questions anytime at help@goldenpaints.com
Its a very interesting subject - so thank you for sharing the interesting research - but it would be helpfull with a short artiklen just on the recommandations 😃🌷
In the case of an acrylic under painting, would it make any sense to add a very thin layer of alkyd medium prior to starting in with the oils? Assume a canvas primed with three layers of gesso, and then one or more layers of acrylic paint…
Hi, Sarah. We do not advise starting with a layer of alkyd medium direct to the gessoed surface. The fact you applied just three layers of acrylic gesso should mean you won’t have any concerns of initial cracking. Adding oil painting mediums in with the paint would be a better approach. But if the acrylic paint is thin and dries to a matte surface, you should be able to start in with oils as desired. Let us know if you have any other questions. You can reach a Materials & Applications Specialist directly at help@goldenpaints.com.
We typically recommend a commercial Direct To Metal (DTM) Primer on raw aluminum. The surface needs to be scuffed and degreased before primer. The Acrylic Gesso can go on after the DTM primer is dry to the manufacturers recommendations. If the aluminum is composite, such as DiBond, then we have found the Acrylic Gesso to have good adhesion to the white polyester surface typical for that material. It also needs to be scuffed and degreased prior to application. Here is an article about painting with acrylics on Dibond that you might find helpful: justpaint.org/painting-on-dibond/
Hello, and thank you for your question. Would you mind emailing our Materials & Applications Specialists at help@goldenpaints.com with a description of the products used and dry times between applications? In particular, they would appreciate a clarification of the underbody you're working on. This will helps them better assist you. Thank you - looking forward to hearing from you.
A popular way to prep boards and canvas is to coat with gac 100 then use michael harding non absorbant acrylic primer. Will this cause cracking when using oils over it?
Hello Starving - we have not tested the MH product, but you can contact us (help@goldenpaints.com) to see what our product support folks know about this or have talked to any artists who've experienced oils cracking over an acrylic ground.
Hi, I use porous Boards which I have sealed with various products, just reacently I painted it with Binder with acrylic over the top, I then use water mixable oils on that. will this crack. Excellent Video.
Hello Ernest, thanks for reaching out. You may find a detailed explanation of the circumstances that cause oil paints to crack when painted over acrylics here: justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/ - if this doesn't answer your question, be sure to contact our product support team directly: help@goldenpaints.com
HA HA HA HA!!!! Well. This is a long post, but bare with me... Doesn't this just beat all. Five years ago (~2016-17) the internet was abuzz about how good it was to use GAC 100 to seal panels and canvas. Now, I have had extensive experience in using acrylics and oils together from my illustration days, and I know when and why oil cracks and why. I have also used acrylic over oil, and vice versa on many occasions. (None of my art has degraded to the point of being trash, but there are cracks in my work that appeared after the first five years, but none have suffered since, nearly thirty-five years later) To use oil over acrylic, the best hope for the medium is to use on panels, rigid support that will not flex. Second, to make sure the acrylic underlayers are dried at least two to three weeks prior to painting upon. Any Gloss medium is NOT a good candidate for any use under oil of any kind due to the nature of the gloss, as it shrinks profoundly during the first few days, and even as long as one month into its life on the canvas. Oil is not a fast reactionary medium, and after it sets up, it will become hard, and only have a certain amount of flex. You call it a "phenomenon" but it is happening due to the shrinkage of the acrylic under the oil that is dried, and a immobile layer underneath. I am not entirely sure if the oil is activating something in the acrylic to allow it to move, or is reaction of off gassing from the acrylic itself due to the solvents in the oil, or if it due to ongoing acrylic off gassing which might be related to gloss. Your tests (I assume) have only been going on for about a year thus far for GAC 100 and acrylic underpaintings, so you have not the longer term effects of these samples. I believe some ill effects will happen in the far reaching future- say about 80 years plus... But these effect are not something I look at to be that much of an issue, as any decent restorationist can mitigate with little skill or trouble. A fast setting oil ground is more brittle than a linseed oil paint film, and therefore be more susceptible to cracking that just regular oil paint. But do you think any of these fact were received by anyone on TH-cam? HELL NO. I got blasted by everyone in the comments, along with the content creators. My recommendations follow very close to what you are saying here, the usage of sandable mediums is completely fine. The reason for this is the additive within these mediums because they generally embolden the rigidity and strengthen the acrylic, along with being a strata that will not flex within the medium of the acrylic paint layer, this above all else minimizes the movement of that acrylic, WHILE allowing the rapid off gassing of the acrylic due to the broken surface tension in the paint film itself. Without the chalk, the plaster, (gypsum) pumice, marble dust, titanium dioxide and god knows what some put into their gesso's, the acrylic will be at risk of cracking any thinner, fast drying oil layer. The flex of that oil layer is the key to its survival. I tend to believe the longer term cracking of oil will happen as the oil ages over top of acrylics, far into the future. Acrylic does lose integrity as it ages, and this is not negotiable to conditions. It will become almost void over time. I have seen paint in some houses that is over forty years old that simply shriveled up under topcoats of paint, leaving a gap of around one millimeter under corner areas of paint. (The thicker areas of paint) In a layer of an oil painting, this is more than significant for delamination to occur in gloss acrylics, and in thinner acrylic coating cause cracking of the oil paint. Gesso's and primers do not follow this same fate, for the aforementioned additives. However, cheaper flat paints do not contain enough acrylic medium to bind over a longer time frame, and this is another such problem artist should watch out for, trying to save money by using cheap flat paint as a primer or in place of gesso. These are a few of my musings of the past ten years, after having done many of the things (successfully, I might add) that people say not to do.
As a follow up to this, (getting into the tail end of this video when you show gesso over GAC 100 or gloss acrylic) The barrier of three coats of gesso over gloss will not save the longer term effect of the underlying layer of acrylic. The problem will still exist, with lessoned effects from the ability of another acrylic layer overtop, but the ongoing issues with gloss acrylic still exist. In 40-60 years, that layer will be a liability to the painting. There will be a point at which the gloss will not support the gesso, and this will be a major issue for the painting. I recommend a PVA glue layer, followed by a mix of PVA and chalk, gypsum and pumice, reduced from that of what is used for gesso, two coats, followed by the full gesso mix, two layers. Each of these layers is sandable, and will give a huge latitude for control of that surface. The gesso can be toned any way the artist likes, but gypsum and chalk are key to enhancing the longevity of that layer for the painting. I am fairly sure this technique will out last the wood panel it is painted upon.
Your test samples seem to be on flexible materials, could the flex be contributing to the cracking? Does it crack the same when it's on stretched canvas?
Hello, there are some examples of cracking created on rigid foam board in this presentation, but even on the flexible substrates, they were allowed to dry flat before the cracking appeared, the cracking does not appear to be related to any sort of embrittlement, so we don't believe the flexibility/rigidity of the support is a factor here.
Good question. An accurate description of a painting that is made of both acrylic and oil paints would be mixed media. When painting with oils over an acrylic Gesso, it would be considered an oil painting.
Are you calling the GAC 100 the gloss medium??? Why cant you put the acrylic gesso over the GAC 100 if you are using it as a sealant for your panel to paint oil on the gesso. I don't get it, one moment you say its ok, then you say it cracks.
GAC 100 is a glossy medium but it’s not the same as Gloss Medium. We’re sorry the video isn’t clear. Our Just Paint article might clarify your questions: justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/. Basically, when painting with oils, we recommend applying acrylic Gesso directly to panels or canvas, without using an acrylic sizing layer. If you do want to apply a sizing layer, then use PVA size. We found that acrylic Gesso is blocks oil sufficiently in about 3 coats, therefor using GAC 100 or Gloss Medium isn’t necessary. When painting in acrylics, sizing with Gloss Medium or GAC 100 is recommended, as the acrylic mediums block SID (support-induced-discoloration, see th-cam.com/video/Csr2Q-cSczI/w-d-xo.html). SID is not an issue when painting in oils. GAC 100, Gloss Medium and similar glossy acrylic mediums have such a potential to cause cracking in oil layers, that it’s best to not even use it underneath gesso layers. You are correct, that the gesso layers will reduce the potential for cracking greatly, but to err on the safe side we’d recommend omitting this layer. If you already have panels prepared with GAC 100 or Gloss Medium and want to use them for oil painting, then we recommend that you add about 5% or more of stand oil or alkyd medium, or 10% linseed oil to the oil paints. We have replied to your other questions as well. If you would like to speak to us directly about your questions, please connect with us via email at help@goldenpaints.com and a Materials & Applications Specialist would be happy to assist you.
@@GoldenPaints Ok. Then I'm sure this advice has changed then and that's why artists are so confused. For years, artists have been buying gac 100 to replace rabbit skin glue and to use as a sealant for both canvas and wood. Then they've been putting acrylic gesso /primer on top of that, instead of traditional gesso.
Can the Golden gesso go directly on unprepared Masonite or hardboard? Can you not oil paint on Golden gesso anymore? So are you saying you cannot use GAC 100 anymore as a ground under the gesso??? very confusing, also, why would I add oil on my first then layer of oil paint, very confusing what happened to fat over lean????? We shouldnt have to call you to get the correct information, please I encourage you to do a good job the first time. Are you calling GAC 100 the 'gloss medium'????
When painting over acrylic layers that have shown potential for causing cracking (see our article : justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/) then adding linseed oil or alkyd medium to your oil layers is recommended and in that case, the medium additions should be added to the oil paints throughout the painting process in order to paint fat over lean.
This video is gold. The guy really knows what he is talking about. Thank you very much
Golden... I see what you did there...
This was fascinating - normally, anything technical tends to cause my eyes to glaze over, but I could have watched another hour of this, quite easily. And that's because you explain the things I really want to know, without digressing into - well - waffle. It's also good - very good! - to find a company that really invests time and money into research: I wish some others did as much, rather than churn out the same old products without showing any curiosity about their performance: the interest of some of them seems to lie entirely in the balance sheet. I should love to see more of these: I do subscribe to your newsletter and updates.
I typed out two question in the course of watching this video, but they were both answered before its conclusion, so thank you for that.
I watched this video just in time before deciding to make more stretched canvas, pondering if I should stick with traditional rsg followed by oil ground or not. The whole "oil over acrylic is ok" is too sketchy for me now. I have experienced cracking on pre prepared oil ground linen canvas glued on synthetic panels and it is pretty awful to see happen. I can only guess the linen was sized with an acrylic layer underneath with an oil ground on top. I shudder at the thought of what has happened to those paintings I have sold before the cracking appeared. So, my conclusion is to stick with what I know works and not venture into any acrylic application under oils. Rsg works and no problems unless you put your painting in extreme atmosphere conditions. All I want is for it to not crack while I am still around due to misuse of materials and buying into companies that push products to buy something unproven. Thanks for doing this video. Now I will be busy buying more raw canvas and doing it all from scratch this summer.
Thanks for your comment. We understand your concerns and would not try to sway you one way or the other. As you mentioned, RSG is time tested and the expectations around the product is well understood. Hopefully the research will continue around modern materials used in conjunction with oils and we will have a better understanding how to safely move forward without risk of unexpected issues. We hope to do our part in that effort!
One way to determine if this is chemical or mechanical is to perform a test on GAC100 or gloss acrylic, but sanded with fine sandpaper to knock down all the gloss. Paint thinned with turpentine is very fluid and has very low surface tension, there isn't much holding it down if the primer lacks tooth or porosity. I've seen something similar when trying to paint urethane varnish over glossy acrylic. It looks fine at first painting, but as it dries the varnish coat will wrinkle dramatically. This is because the urethane varnish is shrinking and can't hold onto the glossy acrylic, the dissimilar films are not bonding, and it allows the urethane to flow however it wants to as it dries.
I watched this video to learn about a problem that I have not encountered: cracking of oil paint layers applied over acrylic base layers. I was pretty interested since acrylic base layers are a key part of my process for building a surface that doesn’t take weeks. The video made me reflect on my own experimentation over the years and what might be behind the ease and seeming (so far!) success of my current process. I will quickly outline it here in case there is scope for further learning through further feedback from other sets of grey cells.
I am currently sticking linen onto pre-sanded ACM using waterproof exterior quality builder’s PVA. I have been a bit surprised that PVA seems to stick better than a couple of glues specifically formulated for sticking to metal. I dry the canvas for a couple of days and then rotary sand (240 grit). Then a couple of layers of super matte chalk paint of preferred colour(s). Sand with 400 grit. Then artist’s oil of preferred TRANSPARENT colours mixed with Penetrol for oil layers adhesion plus Liquin alkyd medium for flexibility. Sand again. Repeat oil layers and sanding for complexity, lustre and mystery. To the touch, this surface is like canvas sex - smoother than silk. The multiple transparent oil layers mean you can see right through to the pattern of the linen in-filled by the chalk paint. Then the piece is ready for adding subject content.
Would love to learn of others’ experience.
Thank you for sharing your layering. The combination of commercial building materials with art materials is interesting. We haven’t tested blending oil paints with Penetrol. Certainly, an interesting experiment. Glad to hear this works so well for you.
its happens to me with Lukas 1862 oils, only with ultramarine blue and cobalt blue, i dont use acrilic underpainting, only guesso (white guesso), excellent video BTW, other thing one thing that i discovered to prevent crackling in my colors is to watch how they dry, and if the start to lock mate to fast, then they problally will crack so i add a thin layer, (like a glaze) of pure linsed oil to them and thats help a lot
Thank you for the feedback! We have not spoken with too many people who have experienced this issue. So, we appreciate you sharing. Very interesting observation about the surface turning matte. We are working with conservators who have advanced tooling to determine the exact causes of matting on oil surfaces when used over acrylics, and if that is a feature of this issue. We are hoping to map out the sequence of events from oil application to when the cracking happens, and to understand the specifics about why it happens with certain products over others etc. We hope to provide additional understandings at some point during the next year through Just Paint.org.
Beautiful my dear friend 🥰👌👌👌 Thanks for sharing
Well received information. Thanks.
Thank you Golden paints, you are so professional. Even if people cannot buy Golden acrylics because they are too expensive in Europe. I was going to start with oil painting over acrylics ! I need time understanding you. If you could, explain in one sentence how to paint oils over acrylics without cracking ? As I understand it: 1. No oil over gloss mediums. or 2. Gesso, applied, min. 3x of clear Gesso. or 3. Mix 10% stand oil to my oil paint, the first layer, probably 5% is enough. or 4. Further oil paint layers need to be fatter.
Hello. Based on our research, those points taken together should provide a successful layering of oils over acrylic. Yes, avoid glossy mediums. White Gesso seems to be more stable than clear gesso, but even the products we have tested labeled as “Clear Gesso” did relatively well with a couple exception. IF the oil layers over top of the Clear Gesso had been modified with oil or oil medium, then it would have likely been totally successful. We just tested lean colors. The oil layers after the first can have the same amount or more medium added. If you have additional questions, please email GWatson@goldenpaints.com and Greg (from the video) will assist you.
@@GoldenPaintsthank you.
I noted : three or more coats of Golden gesso or molding paste - no cracking 🙂❤
I’ve been following the past recommendation to use gloss acrylic as my first coat on the canvas as a size and barrier to prevent SID (substrate induced discoloration) and against oil damage to the canvas. But I also added many subsequent layers including ‘matte high solid gel’ before finally painting on top with oils and I haven’t seen any cracking yet.
Are you recommending avoiding gloss acrylic as a size/barrier even with subsequent layers?
I have just sealed two large cradled birch panels with gac 100. If i gesso over this will i still be able to paint with oils over this ? What im confused on is are you painting diectly over gac 100 as if its a primer ?? Is it ok to use gac 100 as a sealer then acrylic gesso thrn oil paint ??
That was my BIG question, but it wasnt answered !!!
Very helpful video! Thank you!!
When priming an HDF panel with 3 coats of gesso prior to oil painting, should one also paint all sides & back of the panel with gesso in order to mitigate the chances of the panel warping, or is this not necessary? Thanks in advance! 🙏
It can be helpful to cover all the sides of the panel to help equalize tension. You can simply use Gesso, or for a cost savings approach, you can try house paint, house primer or shellac on the sides and back.
@@GoldenPaints Thank you, appreciate it 🙏
Paint drying? Fascinating! Who knew? 😊
Im actually c9bfused can i use gac100 as a size or not ? I have already used it on goldens own recomendation !i was just gling to gesso these panels. Please advise promptly. I shoukdnt have to worry about this since gac100 was sold to me as a great sizing product.
Hi, Shelly. We hope this answers both of your questions on this video. We have always advised oil painters to avoid working directly over any glossy acrylic paint or medium layer. When we investigated why we were getting hairline cracks in the first layer of oil paint, we were able to repeat the issue whenever there was pure oil paint over glossy acrylic products. Therefore, we wanted to bring the test results out into the public eye so that artists were made aware of our discover which also allowed us to get the painting conservation community involved to learn the cause.
In this recorded live demo, around the 23-minute mark, you’ll see Greg address the use of acrylics under oil paints, with the addition of various oil painting mediums. The added oil does a great job to stave off the potential for cracking. The greatest concern in the testing was oil paint direct from the paint tube, so if that can be avoided while you work, you should still be able to use these previously prepared panels. The Just Paint article (linked in the video description) discusses this in greater detail. But if you only paint with pure oil paints and do not add any medium or solvent in your first layers, then three coats of gesso without sizing is the best approach.
Our Materials & Applications Specialists would be happy to chat with you more about this. You can reach them directly at help@goldenpaints.com
@@GoldenPaints You really did not answer her question, can you use GAC 100 as the hardboard sealant with 3 layers of acrylic gesso and be able to paint oil paint on the acrylic gesso without worry of cracking due to the GAC 100 ? In otherwards, Is the GAC 100 a suitable and safe sealant over the panels followed by acrylic gesso for oil or acrylic painting without the cracking ? Telling me to just watch the video again is no help as he is confusing
Late to this conversation, but I'm curious if clear gesso will require less coats over a mixed media work given is has so much more tooth than regular gesso.
I also heard that you still need a good lean but clear oil ground over the absorbent gesso to keep the oil paint and pigments from being sucked into the gesso over time.
Would love some clarity :)
Thank you for your question. We did include some clear gesso and other matte surfaces in our testing, and amending the oil paint with the addition of medium when painting on these surfaces can be good practice. More information may be found in our Just Paint article "Revisiting Oils Over Acrylic" (and its comments) which may be found here: justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/.
We have not seen oil being absorbed by our acrylic gesso over time, however we have seen very absorbent surfaces wick oil from oil paint as the oil paint dries. You might also find our Just Paint article "Differentiating Between Acrylic Gesso and Williamsburg Oil Ground" to be of interest justpaint.org/differentiating-between-acrylic-gesso-and-williamsburg-oil-ground/
Could it be that gloss acrylic takes longer to fully cure than mat acrylic?
Thanks for your comment! The curing time is similar between matte and gloss acrylic products. We tested older acrylic surfaces that had been dry for years with similar result against the same product that were only dry for a week. It likely has more to do with the type and quantity of matting solids in the matte mediums and gels that contribute structure to the acrylic film.
Thank you for sharing. Would you consider airbrush medium close to gac100 or gloss medium?
Airbrush Medium is closer to GAC 100 in viscosity, but is not like either of these mediums in behavior. Since Airbrush Medium was formulated to help Fluid Acrylics be sprayable, it is loaded with so many retarding agents it should not be used by itself. Always mix Airbrush Medium with fast drying acrylic products or the application might not dry. We also do not recommend any of these three glossy products for application under oil paint. Please see these related resources for more information:
GOLDEN Airbrush Medium application sheet: goldenartistcolors.com/resources/airbrush-medium
Just Paint article Revisiting Oils over Acrylics: justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/
Thank you so much for this study report! It was insightful for me as an artist and very intriguing for me as a scientist. I am wondering now if there are any job opportunities for a geologist at your research division...
On our website we have a job listing section. You can always take a look and see what we have available!
workforcenow.adp.com/mascsr/default/mdf/recruitment/recruitment.html?cid=1ad5f229-7e85-4993-8c86-672e31079f3b&ccId=19000101_000001&type=MP&lang=en_US
So if more matte means less cracks, then I wonder if acryla gouache would work as a base? Acryla gouache is really just very very matte acrylic that looks like gouache after all.
We have not tested oils over Acryla Gouache. We did find that when oil paint is applied over our matte SoFlat Acrylics, the acrylic can pull an oil halo out from the oil paint. This might not be an issue if the entire SoFlat surface is covered with oil paint. For more information on oils over SoFlat, see the SoFlat Application Sheet: goldenhub.goldenpaints.com/storage/uploads/SoFlat_Product_Information_02.pdf
11:45 is that oil paint or acrylic color paint also the next one I cant tell if you are spreading oil white paint over GAC 100 or acrylic paint over GAC 100 that is cracking, I was going to use GAC 100 under acrylic gesso for hardbard, but not sure what to do now. Also the question of oil paint over acrylic paint wasn't answered that made sense, so cant you or can you??? I am more confused now. Any way you can repeat this video with more information on exactly what you are doing, with more on what you are painting with etc. Remember we are not researchers out here, just normal people that need a more complete description, it seems scattered more for a researcher to researcher.
What Greg is showing at 11:45 is a laminated card with a wide horizontal strip of GAC 100 applied on the card. The GAC 100 is so clear that it’s not visible. Then the vertical reds and purples are oil paints that were applied to show the differences in cracking that some oil paints have.
To prepare your hardboard panels, we’d recommend to apply the acrylic Gesso directly to the panel, or size with a coat or two of PVA size. There are many different types of PVA glues and sizes available. We’d recommend getting a PVA that is intended for art making.
Can you use clear gesso over acrylic as opposed to white
If painting with oils over a clear gesso, which is similar to our Fluid Matte Medium, we advise adding a little oil or medium to your paint. You may find this article to be a helpful resource justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/
Feel free to reach out to our team of Materials Specialists with questions anytime at help@goldenpaints.com
Its a very interesting subject - so thank you for sharing the interesting research - but it would be helpfull with a short artiklen just on the recommandations 😃🌷
Thank you for this suggestion.
In the case of an acrylic under painting, would it make any sense to add a very thin layer of alkyd medium prior to starting in with the oils? Assume a canvas primed with three layers of gesso, and then one or more layers of acrylic paint…
Hi, Sarah. We do not advise starting with a layer of alkyd medium direct to the gessoed surface. The fact you applied just three layers of acrylic gesso should mean you won’t have any concerns of initial cracking. Adding oil painting mediums in with the paint would be a better approach. But if the acrylic paint is thin and dries to a matte surface, you should be able to start in with oils as desired. Let us know if you have any other questions. You can reach a Materials & Applications Specialist directly at help@goldenpaints.com.
I'm starting using aluminum panels for oil paintings, will the Golden gesso stick to aluminum well??
We typically recommend a commercial Direct To Metal (DTM) Primer on raw aluminum. The surface needs to be scuffed and degreased before primer. The Acrylic Gesso can go on after the DTM primer is dry to the manufacturers recommendations. If the aluminum is composite, such as DiBond, then we have found the Acrylic Gesso to have good adhesion to the white polyester surface typical for that material. It also needs to be scuffed and degreased prior to application. Here is an article about painting with acrylics on Dibond that you might find helpful: justpaint.org/painting-on-dibond/
My oil paint is not sticking to the canvas even after gesso and underbody why ? Help !!
Hello, and thank you for your question. Would you mind emailing our Materials & Applications Specialists at help@goldenpaints.com with a description of the products used and dry times between applications? In particular, they would appreciate a clarification of the underbody you're working on. This will helps them better assist you. Thank you - looking forward to hearing from you.
A popular way to prep boards and canvas is to coat with gac 100 then use michael harding non absorbant acrylic primer. Will this cause cracking when using oils over it?
Hello Starving - we have not tested the MH product, but you can contact us (help@goldenpaints.com) to see what our product support folks know about this or have talked to any artists who've experienced oils cracking over an acrylic ground.
Hi, I use porous Boards which I have sealed with various products, just reacently I painted it with Binder with acrylic over the top, I then use water mixable oils on that. will this crack. Excellent Video.
Hello Ernest, thanks for reaching out. You may find a detailed explanation of the circumstances that cause oil paints to crack when painted over acrylics here: justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/ - if this doesn't answer your question, be sure to contact our product support team directly: help@goldenpaints.com
HA HA HA HA!!!! Well. This is a long post, but bare with me... Doesn't this just beat all. Five years ago (~2016-17) the internet was abuzz about how good it was to use GAC 100 to seal panels and canvas. Now, I have had extensive experience in using acrylics and oils together from my illustration days, and I know when and why oil cracks and why. I have also used acrylic over oil, and vice versa on many occasions. (None of my art has degraded to the point of being trash, but there are cracks in my work that appeared after the first five years, but none have suffered since, nearly thirty-five years later) To use oil over acrylic, the best hope for the medium is to use on panels, rigid support that will not flex. Second, to make sure the acrylic underlayers are dried at least two to three weeks prior to painting upon. Any Gloss medium is NOT a good candidate for any use under oil of any kind due to the nature of the gloss, as it shrinks profoundly during the first few days, and even as long as one month into its life on the canvas. Oil is not a fast reactionary medium, and after it sets up, it will become hard, and only have a certain amount of flex. You call it a "phenomenon" but it is happening due to the shrinkage of the acrylic under the oil that is dried, and a immobile layer underneath. I am not entirely sure if the oil is activating something in the acrylic to allow it to move, or is reaction of off gassing from the acrylic itself due to the solvents in the oil, or if it due to ongoing acrylic off gassing which might be related to gloss. Your tests (I assume) have only been going on for about a year thus far for GAC 100 and acrylic underpaintings, so you have not the longer term effects of these samples. I believe some ill effects will happen in the far reaching future- say about 80 years plus... But these effect are not something I look at to be that much of an issue, as any decent restorationist can mitigate with little skill or trouble. A fast setting oil ground is more brittle than a linseed oil paint film, and therefore be more susceptible to cracking that just regular oil paint. But do you think any of these fact were received by anyone on TH-cam? HELL NO.
I got blasted by everyone in the comments, along with the content creators. My recommendations follow very close to what you are saying here, the usage of sandable mediums is completely fine. The reason for this is the additive within these mediums because they generally embolden the rigidity and strengthen the acrylic, along with being a strata that will not flex within the medium of the acrylic paint layer, this above all else minimizes the movement of that acrylic, WHILE allowing the rapid off gassing of the acrylic due to the broken surface tension in the paint film itself. Without the chalk, the plaster, (gypsum) pumice, marble dust, titanium dioxide and god knows what some put into their gesso's, the acrylic will be at risk of cracking any thinner, fast drying oil layer. The flex of that oil layer is the key to its survival. I tend to believe the longer term cracking of oil will happen as the oil ages over top of acrylics, far into the future. Acrylic does lose integrity as it ages, and this is not negotiable to conditions. It will become almost void over time. I have seen paint in some houses that is over forty years old that simply shriveled up under topcoats of paint, leaving a gap of around one millimeter under corner areas of paint. (The thicker areas of paint) In a layer of an oil painting, this is more than significant for delamination to occur in gloss acrylics, and in thinner acrylic coating cause cracking of the oil paint. Gesso's and primers do not follow this same fate, for the aforementioned additives. However, cheaper flat paints do not contain enough acrylic medium to bind over a longer time frame, and this is another such problem artist should watch out for, trying to save money by using cheap flat paint as a primer or in place of gesso. These are a few of my musings of the past ten years, after having done many of the things (successfully, I might add) that people say not to do.
As a follow up to this, (getting into the tail end of this video when you show gesso over GAC 100 or gloss acrylic) The barrier of three coats of gesso over gloss will not save the longer term effect of the underlying layer of acrylic. The problem will still exist, with lessoned effects from the ability of another acrylic layer overtop, but the ongoing issues with gloss acrylic still exist. In 40-60 years, that layer will be a liability to the painting. There will be a point at which the gloss will not support the gesso, and this will be a major issue for the painting. I recommend a PVA glue layer, followed by a mix of PVA and chalk, gypsum and pumice, reduced from that of what is used for gesso, two coats, followed by the full gesso mix, two layers. Each of these layers is sandable, and will give a huge latitude for control of that surface. The gesso can be toned any way the artist likes, but gypsum and chalk are key to enhancing the longevity of that layer for the painting. I am fairly sure this technique will out last the wood panel it is painted upon.
Thank you
Your test samples seem to be on flexible materials, could the flex be contributing to the cracking? Does it crack the same when it's on stretched canvas?
Hello, there are some examples of cracking created on rigid foam board in this presentation, but even on the flexible substrates, they were allowed to dry flat before the cracking appeared, the cracking does not appear to be related to any sort of embrittlement, so we don't believe the flexibility/rigidity of the support is a factor here.
If I put oil over acrylic is it considered an oil painting?
Good question. An accurate description of a painting that is made of both acrylic and oil paints would be mixed media. When painting with oils over an acrylic Gesso, it would be considered an oil painting.
😊👍🙏
Are you calling the GAC 100 the gloss medium??? Why cant you put the acrylic gesso over the GAC 100 if you are using it as a sealant for your panel to paint oil on the gesso. I don't get it, one moment you say its ok, then you say it cracks.
GAC 100 is a glossy medium but it’s not the same as Gloss Medium. We’re sorry the video isn’t clear. Our Just Paint article might clarify your questions: justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/. Basically, when painting with oils, we recommend applying acrylic Gesso directly to panels or canvas, without using an acrylic sizing layer. If you do want to apply a sizing layer, then use PVA size. We found that acrylic Gesso is blocks oil sufficiently in about 3 coats, therefor using GAC 100 or Gloss Medium isn’t necessary.
When painting in acrylics, sizing with Gloss Medium or GAC 100 is recommended, as the acrylic mediums block SID (support-induced-discoloration, see th-cam.com/video/Csr2Q-cSczI/w-d-xo.html). SID is not an issue when painting in oils.
GAC 100, Gloss Medium and similar glossy acrylic mediums have such a potential to cause cracking in oil layers, that it’s best to not even use it underneath gesso layers. You are correct, that the gesso layers will reduce the potential for cracking greatly, but to err on the safe side we’d recommend omitting this layer. If you already have panels prepared with GAC 100 or Gloss Medium and want to use them for oil painting, then we recommend that you add about 5% or more of stand oil or alkyd medium, or 10% linseed oil to the oil paints.
We have replied to your other questions as well. If you would like to speak to us directly about your questions, please connect with us via email at help@goldenpaints.com and a Materials & Applications Specialist would be happy to assist you.
@@GoldenPaints Ok. Then I'm sure this advice has changed then and that's why artists are so confused. For years, artists have been buying gac 100 to replace rabbit skin glue and to use as a sealant for both canvas and wood. Then they've been putting acrylic gesso /primer on top of that, instead of traditional gesso.
Can the Golden gesso go directly on unprepared Masonite or hardboard? Can you not oil paint on Golden gesso anymore? So are you saying you cannot use GAC 100 anymore as a ground under the gesso??? very confusing, also, why would I add oil on my first then layer of oil paint, very confusing what happened to fat over lean????? We shouldnt have to call you to get the correct information, please I encourage you to do a good job the first time. Are you calling GAC 100 the 'gloss medium'????
When painting over acrylic layers that have shown potential for causing cracking (see our article : justpaint.org/revising-our-recommendations-for-using-oils-over-acrylics/) then adding linseed oil or alkyd medium to your oil layers is recommended and in that case, the medium additions should be added to the oil paints throughout the painting process in order to paint fat over lean.
I fell asleep in the first 5:00 minutes, was the video good?