WEBVTT 00:00:00.000 --> 00:00:01.500 This is Dabalon. 00:00:04.940 --> 00:01:31.860 My name is Trent Reynolds, and in this podcast, I have conversations with artists about materials. If you are enjoying this podcast and want it to continue, please subscribe or make a one-time contribution at dabalon.com forward slash podcast, leave a five-star rating on iTunes and tell all your friends. The longevity of this program very much depends on your support and I thank you. In this episode, I have my first ever return guest, the founder of Gamblin Artist Colors, formulator of most of the products the company makes, and just overall generous and cool guy. I really enjoyed talking with him. Robert Gamblin came back for a materials deep dive. So, varnish. You have probably used it at some point if you paint with oil. But how much do you really know about varnish? I think you might be surprised, as I was, by how little you actually know. It is admittedly, admittedly not a glamorous subject. And we go deep, so hang in there. It's worth it. We cover a lot of good, dare I say important, information. And now a materials deep dive into varnish with artist and materials expert, Robert Gamblin. 00:01:36.100 --> 00:01:52.000 If you don't mind, I'd love to just dig into varnish. Yes, let's do that. You know, as I was thinking about it and kind of writing down some questions, I thought it might be a pretty quick conversation, but it's a fairly deep topic. Okay. 00:01:52.000 --> 00:02:09.660 there's a lot there. Yes, yes, there is. And, you know, we could also get into the psychology of artishing because it's been one of the areas that have, that in my career I have found gives artists the greatest deal of fear and trepidation of almost anything that they do. So. 00:02:10.060 --> 00:02:26.860 That is interesting you say that because I feel that, like personally over the years of Yeah, the psychology of varnishing, that is really, even just the psychology of finishing, right, of deciding that something is complete and letting go. 00:02:27.600 --> 00:02:31.980 Well, why don't we start off with just the basics. What is varnish? 00:02:31.980 --> 00:02:32.500 Yeah. 00:02:32.500 --> 00:03:54.600 Oh, great. That's exactly where I wanted to start is because varnish is so many sort of definitions because of all the different uses in the world. I mean, if you're a woodworker, we're varnishing a table or you can go to the hardware store and all kinds of varnishes are available. And what... What I want to talk about today is just sort of a narrow slice of what varnish is and to define varnish as a removable coating. So many varnishes that are in the world that we can buy for other kinds of purposes, they're not removable. They're intended to be a permanent part of varnish. whatever we have made and have decided to finish it with a varnish. But in painting, oil painting, acrylic painting, our field, especially through the efforts of conservation and conservation science, has sort of, raised the bar and said that whenever we are varnishing, we should be using a material that is removable, and that gives a number of benefits. So whatever we're talking about today, 00:03:55.380 --> 00:04:37.500 it's going to be a removable coating. Got it. So I know there is this sense, and especially you go on to Instagram or something like that, and you see hundreds of videos of people applying varnish, and it kind of goes from this dingy-looking, you know, flat colored, low contrast type of image. And then you put the varnish on and it's shiny and poppy colors and high contrast. So I think there's this, maybe a, just in the way it's represented this thought that varnish is primarily to make it shiny, right? As some kind of finishing top coat. But what you're saying is that there's this added layer of utility that of it being a protective coating that can be removed in order to clean it. 00:04:37.500 --> 00:07:18.080 Yeah, no, it's the other two, two, two big aspects of varnishing. And the primary one, as you said, is, you know, how am I going to finish my painting? What what kind of what can I do to finish your painting, especially Not so much with acrylics because with acrylics, well, actually, it can be with acrylics, too. So I don't want to just limit it to that. But with both acrylic and oil painting, when you say, I'm done, it looks good to me, the surface could be very uneven, right? because you've got a glaze over here and it's had more medium and so that is more of a closed smooth surface and you've got an area over here that's got a bunch of burnt umber in it and we all experience that burnt umber you know sort of really sort of sinks as it dries and it gets very sort of matte and kind of dull looking And between those two extremes, there's everybody else lining up to give their different kind of surface characteristics, depending upon what the pigment is, depending upon the particle size of the pigment, depending upon the oil content of the pigment you've used, depending upon how much medium was used with that particular stroke of the brush or knife. And so you end up with this, you can easily end up with this patchwork of surface that can be unified by using a varnish. Yes, we tend to think that varnishes are glossy But now from most manufacturers, there are options. I mean, just speaking about the Gamblin products, the Gamvar is available in three different surfaces. It's glossy, satin, and matte. Because we've recognized that for the last number of decades, there's a major strain of modern painting that has been all has been built around madness and like I'm at surface and with oil painting that can be really hard to achieve because you know especially consistently yeah the paints have oil in them so they're gonna be glossy and then the mediums all the mediums are pretty much glossy And so you end up with, oh, I wanted a matte surface, and now what do I do? And so a matte varnish can be a very easy way to get that back, to get that matte surface back. 00:07:18.820 --> 00:07:43.060 I do have some questions for you about the gloss, satin, and matte Gamvar products. But before we get to that... What are the ingredients? What are in your typical varnish? I know damar is a common resin used, but what is that? And are there any other kinds of ingredients used? Yeah, in terms of varnishes, 00:07:44.060 --> 00:07:44.900 you know, 00:07:44.900 --> 00:10:58.760 They're generally, especially these new removable varnishes, they're generally pretty simple with a few number of ingredients. So you've got a varnish resin and you have a solvent in which that resin is dissolved. And with many varnishes, especially glossy varnishes, that's it, there's just those two things. That's all that's needed. Because you don't need anything like a dryer because varnishes dry by solvent evaporation. They don't dry by oxidation. So there's no oxidation to speed up or slow down. It's just the solvent's gonna evaporate out of it and it's going to dry. And then if the varnish is going to be less glossy, then a matting agent will appear. Wax has been a historic matting agent in painting for a very long time. And it is still used today. And the route to making gambar mat draws on two things. It draws on a little bit of wax to get the matness going. Then it also has a... more sophisticated matting agents such as fume silica to um to contribute to that say that say that again fume silica yeah fume silica it's it's a very strange material uh i don't know actually how fume silica is made but it almost it almost doesn't exist i mean um Say a typical bag of pigment weighs 50 pounds. A bag of fume silica is two to three times the size of the bag of the bag of pigment, but only weighs 10 pounds. I mean, it's a particle that's sort of like, you know, picture a piece of corn. And then you put it in a popper and it just sort of explodes. And it's good. This goes from a relatively small amount of surface area to an enormous amount of surface area. In fact, it's almost all surface. There's almost not much inside. And that's essentially what fume silica is. It's just sort of this exploded particle with an enormous amount of surface area. And the reason why that is valuable is because it's, The difference between gloss and matte is very simple. Glossiness is smooth and mattness is rough. And so if you and all these varnish resins will produce a very sort of smooth, microscopically smooth surface. And if you want to change that to being a matte surface, you have to microscopically roughen it up. And this fume silica is a very valuable tool to be able to do that because it has so much surface area. 00:10:59.380 --> 00:11:05.660 But because it's silica, it's inert and it's not going to affect the chemical composition of the mirror. Yeah. 00:11:05.920 --> 00:11:12.100 And it has like no interior space. And so it's like you get it wet and it's like totally transparent. Yeah. 00:11:12.100 --> 00:11:23.460 Would you use calcium carbonate or something like that that is used in oil paint? It's a filler, but would it be used as something to make something more matte? 00:11:23.660 --> 00:12:13.100 It would never be used because it has, even though we consider that a transparent pigment, it is not nearly transparent enough to be used as a varnish. in a varnish because we want absolutely all the light that is possible to pass through the varnish and hit the painting. Because the varnish isn't the painting, the painting is underneath the varnish. And so you want all the light possible to pass through. And if you put some calcium carbonate or aluminum hydrate in there, one of those transparent pigments, then that would bounce some light back out. And so it would be tending towards putting a fog, a slight fog on your painting. 00:12:13.680 --> 00:12:29.040 Got it. One more question about the fume silica is, does it have any abrasive quality to it? So like when you want to go to remove the gambar, is there a concern that it might, you know, roughen up the surface of your painting? 00:12:29.420 --> 00:12:46.300 No, I don't think that that's generally a problem. There's really a very small amount in it. And once you re-wet the coating to remove it, it will just sort of wash away. There's not a lot of scrubbing required. 00:12:46.300 --> 00:12:51.640 And the Damar resin that you use in Gamvar, is it Damar or is it... 00:12:51.640 --> 00:16:53.200 Okay, great. Yes. We started out there. We started out that what are these things? And it's important to, I think, make a distinction. Okay, so we've got varnish resins and there are natural resins. resins that are produced from trees or even bugs. So everyone knows primarily about damar. Many people know about mastic and many people know about copal. Those three are natural resins that are secretions from a tree. and you can knock off the resin from the tree. It's really pretty hard, sometimes really very brittle. You could hit that chunk of resin with a hammer, and it would just sort of shatter like a piece of glass. Those are the natural resins that are primarily available for, have been used in painting as varnishes for hundreds of years. Now, and then there are the modern synthetic resins. Gamvar is based on a modern synthetic resin, and it is a resin that is not easy to understand what it is. It's called a hydrocarbon resin. Well, what is a hydrocarbon resin like? I don't really know. You know, it's some, it is a, I couldn't tell you how it's made. And there are other resins that we use at Gamblin for other purposes called an aldehyde resin. And I can't tell you how an aldehyde resin is made either. Some of these modern synthetic resins, like, they don't come from a tree. You can't go knock a lump of hydrocarbon resin off a tree and, like, turn it into, you know, these are actually... sophisticated man-made resins. But so we have natural resins and we have synthetic resins. Now we can further divide the category, just sort of one more level of complexity here. And this is really a very important one to understand. And that is some of these resins are very low viscosity and some of these resins have a much higher viscosity. And that generally is related to the particle size. So all this low viscosity resins, which is everything we've talked about so far, damar, mastic, copal, aldehyde resin, hydrocarbon resin, those are all resins with extremely tiny particle sizes. and so they make low viscosity varnishes. There are some high viscosity resins that are available. And like if you are, you know, if you many, many painters certainly paint in acrylics and, you know, they've gone to, you know, the Golden Rack and looked for their varnishes and Golden has their MSA varnishes. which is mineral spirit acrylic, which is based on poly butyl acrylate. And that's an excellent varnish, but it happens to be a high viscosity varnish. In other words, the particle size is really quite large. And where the rubber hits the road with this low viscosity, high viscosity varnish, is how the varnishes interact with light. Personally, I believe that it is important to match the varnish, the particle size of the varnish, with what the medium that the painting is made from. So oil painting is a low viscosity medium. Oil itself has an extremely tiny particle size. 00:16:54.080 --> 00:16:54.800 And... 00:16:54.800 --> 00:18:15.620 Boy, now we're going to get down to one last rabbit hole, and that is to talk about refractive index. So all this low viscosity, high viscosity, particle size, what it really controls on the painting is how the painting interacts with light. And materials that are very small and are low viscosity, they react with light in a certain way that gives a very high refractive index, which means that actually the colors can be really sort of very intense. And so if you have a, low viscosity varnish on top of a low viscosity paint, you know, like Gamvar on top of oil painting, then you have two like materials. And where those two materials come together is since they have very similar refractive indices, light does not see that it has a barrier and it passes right through. So the light passes through the gambar, passes through that barrier, hits the particles of pigment in the oil paint 00:18:15.620 --> 00:18:18.400 and bounces back out. 00:18:18.400 --> 00:19:16.700 If we were to put a high viscosity varnish on top of a low viscosity paint, therefore, is that essentially putting an acrylic varnish on top of an oil painting. Since the refractive index is more different between the varnish and the painting, right where those two come together, light is going to see that, experience that as a barrier. And some of the light is going to be rejected at that interface. And some of the light is going to get through. And so we're not talking about an enormous amount of light, but we're talking about a difference. And so... And so there can be a decrease in sort of the intensity of the painting when a high viscosity varnish is put on top of a low viscosity paint. 00:19:16.700 --> 00:19:23.320 - What would be an example of a high viscosity paint that would be compatible or... - Oh yeah, acrylics. 00:19:23.320 --> 00:19:41.320 You put a golden MSA varnish on an acrylic painting. You got a high viscosity, large particle size varnish on top of a high viscosity, large particle size paint. And it's a perfect match. It's a really good marriage there. 00:19:43.420 --> 00:23:27.100 And that last little story that I told is how all of this got going. I think in the last time we talked, I mentioned Rene Delary. I probably talk about him as often as I can. He is, you know, probably the most influential conservation scientist that has come around who has done research on raw materials. And so most of what I'm telling you, I've actually learned from him. I didn't invent this stuff myself or discover it. I learned it from him. And so he started out at the Metropolitan Museum and then was the head of the science department at the National Gallery for over 20 years. And he focused on varnishing because he found that... After these modern synthetic resins were invented in the 1960s, the early versions of them were only high viscosity varnishes. And so since they are very stable in terms of their color, and very good in terms of not yellowing or darkening or anything, conservators were putting them on oil paintings, you know, kind of left and right. And after doing that for like 15 years or so, they noticed like, oh, my God, you know, the collection just doesn't look as good as it used to look. And so, and because they're putting, they put a, you know, a high viscosity varnish on top of low viscosity oil paints. And so there was light being rejected at the interface between those two materials. And so they ditched the modern synthetic resins and started going back to Damar, which, you know, made the paintings look great. But here's the problem with natural resins, which we haven't mentioned yet, is that. And this is the reason the modern synthetics were invented, is that all natural resins, damar, mastic, and copal, they do not age very well. They all darken. They all yellow. They all become very, very difficult to remove the older that they are. And there have been sort of countless paintings that have been damaged by over the centuries as conservators have removed these varnishes from paintings because it takes an extremely strong solvent to do that work. And in the process of doing that, you know, it has been very easy to strip subtle glazes off of the painting because, you know, before, you know, high magnification, how could you tell the difference between a dirty varnish layer and a moody glaze layer? You can't tell. And so a lot of these were sort of stripped off by accident. And so anytime in my, this is me speaking, not a conservator speaking, that anytime a conservator uses a natural resin to re-varnish a painting, they have set the clock ticking in which that painting will have to go back to the conservator, for removal because it will, over time, change the values and the intensity of the painting to the point where they're gonna wanna remove it. 00:23:27.100 --> 00:23:32.440 - Is there a known time limit for that, for just a traditional DeMar varnish? 00:23:32.440 --> 00:24:37.600 - No, I think it depends a lot on the environment, how clean the environment is, how much light it gets. But you know, Most paintings will get treated every 100 to 150 years or so because of these kinds of issues, I think. Except for the Mona Lisa, that one, the French have not had the guts to take its varnish layer off. And what I have heard is that- is that the varnish layer on the Mona Lisa is extraordinarily thick because the only thing they've, they've had guts to do is to, is to re varnish it. And so it is, has layer and layer. Um, but there have been many Leonardo's that have been, um, that have been worked on in, in recent years. And, um, very successfully, especially at the National Gallery in London. They have done great work on Leonardo's. And so hopefully someday the French will get the guts to touch the Mona Lisa and take off all the varnish and give her a fresh face. Oh, my goodness. That's just me talking now. That's enough. 00:24:37.600 --> 00:24:50.960 Okay, so so gambar is made with not with the Morris made with a synthetic varnish Yeah, it's a hydrocarbon resin and it has advantages over the natural resins because it doesn't have this 00:24:51.500 --> 00:25:57.240 Kind of time limit that you that you were talking about. It has as many a varnish many advantages one is that a it remains stable in terms of its color and transparency as long as it's ever been tested. It's been artificially aged out over 100 years, and it remained as clear and as clean in color as it was when it was applied. And very importantly, it's... remains as easily to remove after that aging as it was when it was freshly applied. And the third thing that is super important to me, and I think to many artists who are trying to work in safe studios, is that many varnishes require varnish. you know, a pretty strong solvent to make them work. You know, like Damar, Mastic, and Copal, you have to dissolve them in turpentine, which is a pretty strong solvent. 00:25:59.420 --> 00:27:47.220 But... This hydrocarbon resin, which is known as regal res, that Gamvar is made from, actually dissolves in Gamsol, which is a 0% aromatic solvent. This is mild mineral spirit as can possibly be produced. And so, and I think many of your listeners are very familiar with, with Gamsol and know that it, you know, it has no odor and it's very, very easy to work around. It's very safe solvent and Regal Res. That hydrocarbon resin that is Gampar is dissolved in it. And here's something that points to the trepidation that many people have with varnishing. It's like, what happens if I varnish my painting and I don't like it? Well, if you do that with Gampar and you don't like it, you just take... Gamsol again and re-wet the surface and it comes right off. One thing that I found that personally that I find very valuable with that is that, we all make paintings, we put them up on the wall and two years later you think like, "Oh, look at that spot. That spot bugs me. Why did I do that? Why did I paint that color there?" And so if you've that painting is varnished with gambar, you can just take it off the wall Remove the varnish just from that area. Hmm. Not the whole thing You know repaint the area let it dry kind of an appropriate amount of time and then just re varnish that one little area and it will it will knit perfectly together and it makes it very easy to handle. 00:27:47.400 --> 00:28:05.260 I was going to ask you about that because, you know, I've had many experiences with DeMar that it can be pretty finicky. Like it starts to set and you don't want to mess with it or you're going to get, you know, little goobers and all sorts of, you know, problems can happen with the MAR. 00:28:05.780 --> 00:28:09.160 Yeah, and that's a lot of that is because of the very fast evaporation rate. 00:28:09.620 --> 00:28:33.020 Exactly. So with Gamsol, it's not as evaporative, right? It doesn't happen as fast, so you've got more time to futz with it, to mess with it. But I also imagine that also means that when you remove it, you're not going to get as much of that agitation that you would get, you know, because of the fast evaporation time with terpeno, terpeno. Yeah, exactly. 00:28:33.300 --> 00:28:34.580 It comes off really quite easily. 00:28:35.040 --> 00:29:38.140 So you can, you can treat it locally instead of just having to take the whole thing down. Yes. Yeah. That's interesting. I hadn't realized that. I did notice recently when I was using Gambar that it is not nearly as stinky as DeMar. DeMar is so, so potent. You don't want to do it in a poorly ventilated area. Yeah. Herbentine is quite a strong solvent, yes. So like a traditional painting medium, like a three-part medium would be, you know, one part Damar, one part English distilled turpentine, and one part stand oil or linseed oil, right? Yes. When you mix the varnish in with your medium... Does that affect its stability when you then varnish a final varnish and then want to remove the varnish? Because the varnish is also in your medium, does it compromise the painting at all? Do you understand my question? 00:29:38.140 --> 00:30:01.460 So your question is, if you're using a varnish with a natural resin component in it, And then you varnish with a natural resin component. Is that your question? Yeah. So are you talking about using a natural resin medium and varnishing with a synthetic resin? Which are you asking? 00:30:02.160 --> 00:30:26.000 I guess I hadn't thought of there being a difference there. So let's start with the natural resin. So if you paint with a natural resin mixed in with your medium, and then you use a natural resin varnish on top, and then you remove the top layer, is it going to compromise the painting itself because it has natural resin mixed in with the paint? 00:30:26.000 --> 00:32:09.880 It certainly is possible, absolutely. And that is when I was talking about those countless paintings damaged by removal of varnish, that's exactly what was going on. Where using the strongest solvent on the shelf to take an old varnish off. You know, it doesn't know when to stop. Right. Exactly. If you don't if you're not working with it very judiciously, then it'll just keep on going. And and who knows where it will stop? So, yes, that has been historically a very big problem. I mean, I. You know, I think I was at the Tate Gallery once many years ago. I came around a corner and I saw the brightest, most, you know, cleanly looking Turner painting I had ever seen. And I thought, oh my God, somebody just not only took the varnish off, but, you know, just... You know, they just took off all of his, you know, milk guilt glazes also, you know. And so, yes, it is. It has. It has certainly happened. And that is I mean, if you are one of the few oil painters left in the world still using natural resin painting mediums, it's a really good idea to use synthetic resin varnish because if that varnish, when that varnish is taken off, it requires a very mild solvent and it won't attack your painting or your glazes underneath. 00:32:09.880 --> 00:32:19.200 - Got it, good to know. What about using the synthetic resin on top of the painting that you've used the synthetic resin mixed in with the paint? 00:32:19.200 --> 00:32:35.320 You shouldn't use, that's a very, very good point and I'm super glad you asked that, is that Gamvar, the Regal Res varnish that it is made from should never be used in the paint layers. It is only a final varnish material. 00:32:35.940 --> 00:32:46.980 Got it. Okay, so that's a difference from the mindset of maybe more traditional techniques, right? You do not use Gamvar as part of your painting medium. 00:32:47.340 --> 00:32:50.480 Exactly, yes. Okay, that's good to know. 00:32:51.600 --> 00:33:02.620 Would you recommend just getting rid of DeMar varnish as part of, you know, your medium mixture altogether and use other options? Or are you a fan of DeMar? 00:33:03.480 --> 00:33:52.500 No, I mean, that has been sort of a crusade, if I call it properly, of the company for many decades was to... decrease the level of harmful materials that are in a painter's studio. And the first target was to get turpentine out. And that meant that natural resins had to go with it. And, you know, Rene Delary was the one who gave me all the ammunition to do that because he You know, in one of his papers, he starts out by saying natural resins are the least stable of materials in an artist's studio. And so essentially he was saying, like, you can get rid of them. It's time. It's time to let them go. 00:33:52.500 --> 00:34:07.260 Got it. That's interesting. Okay, so Damar is gone. Damar is gone. Turpentine is gone. In its place, we have some other options as putting into a painting medium. 00:34:07.860 --> 00:34:28.960 Yes, I think the best options that are on the market today, made by Gamblin, made by Windsor Newton and other companies, are mediums that are based on alkyd resins. Alkyd resins are very, the name itself is confusing. 00:34:31.200 --> 00:35:00.980 But they are essentially, how I come to understand them and try to describe them more carefully, more clearly, is that they are made from oil. But that oil is so highly polymerized, which is what oil does when it dries. No matter what you do with an oil, the road to drying is through polymerization. And so by pre-polymerizing the oil in a medium, you help it to dry quicker. 00:35:03.340 --> 00:35:03.900 And... 00:35:03.900 --> 00:36:02.900 So, alkyl resins are oils that are so highly polymerized that they tend to dry more like a varnish through, or more like a resin through solvent evaporation. So when when with most alkyd resins, there are there there's solvent in there that are keeping the the the chains of oil apart because when they touch it, it dries. And so the reason why it's called a resin is because it dries very much like a resin rather than an oil, even though the bulk material that the alkyd resin is made from started as oil. And is that oil nature that it has makes it so accommodating and so such a great partner with oils themselves. 00:36:02.900 --> 00:36:40.500 I'm going to ask you a question that is, you know, you can reject it. I, for years, used a Windsor and Newton product called Liquin. Yes, an alkyd resin. Which is an alkyd resin, and I, for years, would recommend that to students. I have found over the years, though, that it seems to get really yellow and brittle. Is that... Can you make a comparison between the alkyd mediums that Gamblin produces and the Liquin? 00:36:41.140 --> 00:37:53.280 All oil-based materials change color as they age, whether it's oil itself or alkyd resin. They are all going to change colors. And a lot of that, the exact color that you're looking at is determined by just how much light the material is getting at, you know, recently. Because you take any oil painting, no matter how it's made, and you put it in the dark, and it's going to change color. It's going to warm up in color. You know, I've measured this with a spectrophotometer. is that it happens. But then you bring it back out and you put it in the light and it will recover. Now an age painting doesn't look like a new painting. But a lot of the issues I think of disagreeable yellowing that I've seen in my career with alkyl resins of all kinds have come from two factors. One is like, oh, they just took it out of the rack and it's been in the dark for three years. That's one issue. Another issue is that, 00:37:55.660 --> 00:38:49.200 I don't hear about it so much anymore, but for a while it seemed to have been a rage to use alkyl resin mediums as a final varnish. and so that has put just a layer of oil on top of everything and sometimes not a thin layer of oil and the thicker it is the more color that there's going to be as an age and so that is something that I think we should also make very clear in this little podcast is that painting mediums are not varnishes. painting mediums are used to be in the paint and not to put on top because they are not, they're not formulated for that. They're not formulated to be, you know, to keep the color perfectly. They're formulated to dissolve color and make it work, make it move in a specific way. 00:38:49.200 --> 00:39:10.440 And they won't be removable like a varnish, right? And they're going to yellow more over time. Do I understand correctly then that if you do have yellowing, that it can be improved by exposure to sun? Like does UV bleach that yellowness? It does, yes. And then, yes, exactly. 00:39:11.580 --> 00:39:12.100 Okay. 00:39:12.100 --> 00:40:37.800 uh, in fact, in one extreme case, um, I, I had, I had a white painting on, on a wall and it wasn't even in the dark, but it was in the wall. And I just decided I'm going to, I'm going to measure, I'm going to shoot, I'm going to shoot this painting with a, with a, with a, um, spectrophotometer to measure, to measure its color, to measure the, the, the, the quality of its color every week. And I noticed that even though it was sitting on the same wall with the same light exposure, the color, the reading I got into the spectrophotometer was different every week. And I did this for over a year and I graphed the results and I could tell that from my results, just by looking at the graph, I could tell you when summer was, I could tell you when the middle of winter was because there was less light and less sun coming in that room. And I came to believe that oil paintings not only respond, the color not only responds to whether they're in the rack or on the wall, but they are responding constantly to the amount of light that they get. And of course, our eyes are not spectrophotometers, we can't really tell the difference, but that machine can tell me the difference. - That's really interesting. 00:40:37.800 --> 00:40:58.300 I've got some questions about the Gamblin, Gambar products. You've got satin, matte and glossy. I have received disturbing news from Canada that a art supply store worker told one of my friends that Gamblin is no longer producing these products. Is that true? 00:40:58.300 --> 00:41:37.700 No, that's not true. The problem, one of the regulatory agencies in Canada wanted documentation that the child proof caps had been tested on those specific bottles. So not only did they require that you have childproof caps, you know, on a material that has solvent in it, but that you have actually had those products tested in the laboratory that they meet the standards for childproof caps. 00:41:37.700 --> 00:41:47.380 And that I'm just imagining a laboratory, a laboratory with a bunch of kids. 00:41:48.580 --> 00:41:56.900 Well, you have you have how do you test that you have pictured absolutely correctly. That is exactly what they do. 00:41:56.900 --> 00:41:59.960 Is that really what they do? 00:42:00.040 --> 00:42:19.100 They bring a bunch of kids in there trying to open it? They get a bunch of kids in a room, and they show them the bottle, and they spin the cap around. And then they hand it to all these kids, and they say, okay, now take the cap off. And, you know, if they can do it and figure it out, then it's not a childproof cap. 00:42:19.320 --> 00:42:31.960 I don't know why that is so funny to me, but just that image for some reason. So that's interesting. So that's actually what they do. So it's not the fact that, I mean, you do have childproof caps on them, but the Canadian government wants the documentation. 00:42:32.420 --> 00:42:32.920 Yeah. 00:42:32.680 --> 00:42:53.700 We didn't have a piece of paper that said that this cap on this bottle had been tested correctly. to that standard. And so I think it just took some time to get that done. But no- You better be paying these kids minimum wage. I don't know. I wasn't on that part of the food chain, so I don't know how they made it. 00:42:53.700 --> 00:42:58.820 out. Application, do we brush it? Do we spray it? How do we get this on there? You know, 00:42:59.100 --> 00:46:41.680 we all go to YouTube these days, right? To figure out how to do something. That's what I do. And so like everything else, I think a lot of artists are going to YouTube to get their questions about how to varnish answered. And I have... I have been slightly horrified and it caused me to wonder like, wow, what about everything else I'm seeing on YouTube? I hope I'm not being led astray. Because one thing that's really important, I believe, with varnishing a painting is to apply a thin layer as possible. And I'd like for people to actually think of varnishing as actually is not putting a layer on a painting, but just doing what they can to change what the surface is. And so I think by with having the idea of putting an additional layer on, it has allowed a lot of artists to change. apply too much varnish. When too much varnish is applied, it can be overly glossy. That, what I would describe as a thick layer of varnish, can trap solvent down in there for a very long period of time, which will prevent the surface from hardening up. And that's what we want. We want a varnish to have a real hard surface. And also, a varnish is not your painting. So you want as little of it on as possible so that the world, the light of the world is interacting with the painting and not so much with the varnish layer. And so I have a technique that I'd like to recommend is that when you varnish like this, Varnish flat, lay the painting out flat, so you don't have to worry about drips and all that stuff 'cause it's a very low viscosity material. And then put what you might think of as a generous amount of varnish on there with a wide brush. Don't use a skinny brush, use a wide brush. And varnish brushes, when you get one, it's a very thin brush, it's not a thick brush. It's thin and it's wide. and buy a good varnish brush and don't let it touch anything but varnish. Don't wash it, don't use it for glazing, don't use it for applying ground, don't use it for anything else but varnishing and it stays pristine. Yes, when you're done, the brush is gonna harden up a bit. But then when you soak the brush in varnish before using it again, it'll come nice and soft and pliable. But you won't put any detergents in there, you won't put any water in there, you put nothing in there. And so using that wide brush, varnish the painting all over. Generally on YouTube you see painters pouring varnish right out of the bottle into the middle of the painting. That's a really good way of getting a lot of varnish on, too much varnish on. You don't need that. Generally, what I have is a small cup to the side, and I dip my brush, just the tip of my brush, in that cup so I can control just exactly how much is going on at any one time. Now, I purposely put too much on at the beginning, not a huge amount, but I wanted to get down into all of the structure of the painting. So I have a little bit too much. 00:46:42.740 --> 00:46:46.600 And then, you know, you know, I... 00:46:46.600 --> 00:47:27.600 go get a cup of tea or something and come back. And I have this pad of paper towels that I have arranged. And the next step is going to be to remove as much of that varnish as possible using the wet brush. So... get back in and start brushing the painting and then wipe the brush on the paper towels and that will suck all the excess out of the brush. Go back to the painting and brush some more and then go back and forth between the paper towels and the painting and you will end up with an extremely even coating of varnish all over the painting. 00:47:27.600 --> 00:47:36.800 And you will, when you're going back and forth, uh, you know, in this, this second stage, are you brushing in opposing directions? 00:47:38.000 --> 00:48:34.320 Or does it matter? Totally randomly. You know, I brush, I brush top to bottom, I brush side to side, and then like, all over the place because after a while, it certainly doesn't matter. You've got so little varnish on there and it's all gonna be the same thickness. It doesn't matter which way you brush because it's all gonna sort of flow together. It's not going to be, not going to be stripy at all. And so, but that using the brush to use brush to apply varnish, use the brush to remove varnish so that you have absolutely the smallest amount of varnish on there. And I guarantee you the painting will look absolutely beautiful. And you will, all of the painting that's there will be sort of dominant. A thick varnish layer will not be interfering with with the experience of your painting. 00:48:34.320 --> 00:48:46.340 - Got it. You're buying a big brush. Can you recommend like a width? I guess it probably depends on the size of the painting. If you're working on a four foot painting, you probably want a bigger brush than if you're working on a-- 00:48:46.340 --> 00:49:09.760 - Well, I actually think it doesn't matter. You can't really buy a brush too big. I mean, I saw Mark Leonard, who was the head of conservation at the Getty, varnish a painting in demonstration several years ago. And the painting was small. It was like, you know, 12 by 16. And he had like a four inch brush that he was using to varnish that painting with. 00:49:10.540 --> 00:49:12.900 And there are specialized varnish brushes. Yes. 00:49:12.900 --> 00:49:19.560 Yeah, well, yes, you'll find varnish brushes on the market and there's some really good ones. 00:49:21.800 --> 00:49:41.280 Gamblin has a good brush that they make. Da Vinci has a good brush that they make. And, you know, there's Italians make really good brushes also for varnishing. But essentially what it is, is it's wide and it's thin. 00:49:41.660 --> 00:49:46.700 There are aerosol products that are, what is it called? It's a... 00:49:46.700 --> 00:52:24.400 workable varnish or I know that a lot of spray varnishes are used they're used because they're they're easy you pop the top you shake it up and you spray your painting and you're done bam you're good generally a lot of those that I've seen have ketone resin varnishes in them and those are synthetic low molecular weight varnishes like we have been talking about but generally aren't quite as stable as like a Regal Res would be. But I think they're good material. My trepidation personally with them has always been the form factor. where there are, anybody who has used a spray can knows how difficult it is to get an even coating on. You know, you've got a big, you've got a big blurb there, and then there's sort of nothing around. It's so difficult to get a good even coating. I've seen descriptions of how to try to do it. You start spraying before you get to the piece and you move across and you spray after you've gone through the piece and then you go the other way. I mean, if you do it that way, you might be able to get a fairly even coating, but you can't rework it. I mean, the solvent evaporates so fast that you're just left to spraying. And with a liquid varnish and a brush, you're totally in control of what happens. And a spray, it's just sort of you're left at the mercy of how good that sprayer is on that day and your ability to spray it evenly. Got it. Yes, they are used quite a bit. Actually, I must say that I just recommended a spray to a good friend of mine. He called me with a problem. He says he uses gambar. He loves it. Absolutely. But on this painting, he did he did some very delicate colored pencil lines and he was worried about furnishing them because, you know, colored pencil is essentially, you know, a wax based. you know, crayon and brushing it with gambar would probably smudge those. And so I recommended that he get, you know, a good artist's varnish in a spray can and just spray that area where that colored pencil is and then use gambar on the rest of the painting and He did so and he was very pleased with the results. 00:52:24.400 --> 00:52:29.240 - Gamvar would be compatible with natural resin varnishes? Like you could-- 00:52:29.240 --> 00:52:36.840 - No, this is not a natural resin varnish that he used. He used a spray can that had like a ketone resin. 00:52:36.840 --> 00:53:15.920 - A lot of artists make the mistake of adding too much solvent in with their paint as they're painting. and to get drips or to get washes, to get oil paint to act more like watercolor, right? - Yeah. - I got the question from a friend, if you did that, if you wanted to get those kind of drippy, solventy types of marks, and the paint structure was compromised, Could you varnish on top of that to seal it and to solidify that? Or what would be the right way to solve that, to fix that structure problem? 00:53:16.600 --> 00:53:56.740 Yes. In conservation, they would call that a consolidating layer because they run into that a lot where, you know, a coating is so old, it's just starting to crumble. And in this case, it's not old. It's just underbound. And so in conservation, they use consolidating layers quite often. And yes, you could use a varnish for that. The danger would be is that if that varnish was removed, then, you know, that could cause those materials to start to move around. It's certainly possible. 00:54:00.540 --> 00:55:35.740 An artist's consolidating layer could be made, it's not something that we talk about very much 'cause the question doesn't come up very much at all. But if I was to make a consolidating layer today with a painting that was done, it's a totally completed painting, it's an old painting that's done, and I wanted to consolidate it, I would probably take a very dilute, I would see if this would work, and it very well may work, take a dilute PVA paint, You know, Gamblin makes one, their PVA sizing is actually a very dilute PVA. And I would paint a very thin coat of that on top of those areas where I was worried of them not being bound enough. I have heard of... are just using the PVA sizing as a fixative for pastels, which is essentially a fixative for pastels as a consolidating layer for pastels. And so I've seen it work for pastels, and I think it would work on an oil painting. You might have a little problem with it beating up water on a closed oil surface. but I think with a little bit of agitation you might be able to, or reapplication, you might be able to get that to work. 00:55:36.100 --> 00:55:45.660 Interesting. So even though it's an oil-painted layer and PVA is water-based, right? Yes. You could use a PVA size on top of that to seal it. 00:55:46.060 --> 00:55:53.760 It might work, but you'd have to deal with the surface tension of water to get it to lay down, but I think it's possible. 00:55:54.200 --> 00:56:19.340 Got it. - Okay, my last question would be having to do with, again, another question from a friend who after she completes a painting, she ships them, rolls them first. Is there any way to prevent or minimize cracking of varnish when you roll up a painting? 00:56:20.920 --> 00:56:29.640 - There shouldn't be any danger in a varnish cracking. I would worry about a paint layer cracking before I would worry about a varnish layer cracking. 00:56:29.640 --> 00:56:32.420 Are these oil paintings or acrylic paintings she's rolling? 00:56:32.420 --> 00:56:34.740 - She's rolling oil. - Okay. 00:56:36.800 --> 00:57:40.080 I would certainly make sure, and she probably does this, that the core that she is rolling it over is no smaller than six inches. And then, you know, we test once a year, we test all of our colors and we bend them over a one inch mandrel. And so we expect all of our colors that have been aged one year to bend over a one inch mandrel, which is sort of a one inch core without cracking. And so a six inch mandrel. core to roll over is, you know, rolling out, the painting is on the outside of the roll, and the core is six inches, no matter what that person has used, except for maybe if it was a, you know, a thick wax painting, a thick wax painting may not take a six-inch core, but a normal oil painting does. and varnished oil painting would usually do that without a problem. 00:57:40.380 --> 00:57:46.860 And just to be clear, the six inch, is that circumference or is that diameter? That's diameter. Okay. 00:57:49.060 --> 00:57:53.300 If there is cracking in the varnish, how do you deal with that? Mm-hmm. 00:57:53.300 --> 00:58:26.100 Well, depending on what kind of varnish it is, I've never seen gambar crack, so we're probably talking about damar. And I would imagine that if it does crack, it's too thick. And you could probably varnish it again without removing it, and the varnish would fill in those cracks and make them sort of go away. as an alternative to removing it and re-varnishing. 00:58:26.100 --> 00:59:05.400 - Got it, because varnish re-wets when you, I mean, just like you're saying with not cleaning the brush because once you get it wet again with varnish, it'll re-wet. Say somebody was using, I've got a whole slew of questions about wax another time, but if a wax top coat, like a Dorland's wax or something like that, if it is cracking, say you've applied it to a canvas and the canvas is flexed or something like that, if a wax top coat is cracking, can you heat treat it from behind to re-melt the wax or does that not work? 00:59:05.400 --> 00:59:06.780 Does that not work? 00:59:07.320 --> 00:59:53.300 I imagine you could, but I would probably hit it from the front. You know, I would take a, you know, what I would do if I found that I had a wax varnish that had cracked on the surface, I would take, I would certainly test this on something else to see, but I would take a hairdryer. and try to keep quite a distance from the painting until I've just found that sweet spot where there was enough heat to re-melt the wax and have it sort of go back together. But I think a hair dryer would be plenty hot enough, but I certainly wouldn't get it too close where I would start pushing the wax around. 00:59:53.300 --> 01:00:01.620 Right. Is the Gamblin cold wax medium, can it be used as a top coat or is that not really a... Yes. 01:00:01.800 --> 01:00:07.680 No, it's used all the time. It's been used on hundreds of paintings for that purpose. 01:00:08.260 --> 01:00:15.020 Okay. And is it pretty flexible? Like you could do it on canvas. It doesn't need to be a rigid support? 01:00:15.460 --> 01:01:32.380 Yes, because the amount of... I find a little surprising the question of a cracked wax varnish because the amount that is being put on generally to be a surface modifier is so thin that there's just almost... sort of none there. And that's sort of how I feel that it is best. You can apply the wax medium with a soft cloth and circular motions, just put it on. And then you come back you know, a few hours later in the next day. And with a soft cloth, again, you can gently buff that and you can, you know, remove any excess that way. And you get a really sort of luscious, waxy, sheen. It's not actually highly glossy, but it's just really sort of seductive beautiful surface that wax gets by, you know, it's like polishing your shoes. That's wax too. You put it on a bunch and you come back and you buff it and you get a nice little shine. If you don't want that shine, then yeah, you would not want to touch it again. in after you applied it. 01:01:32.580 --> 01:01:42.520 As before, I really, really appreciate your time and so much knowledge and expertise to share. It's been a fantastic conversation. Thanks for being so generous with me. 01:01:42.700 --> 01:01:47.200 Thank you, Trent. I've really enjoyed the opportunity to speak with you. 01:01:47.200 --> 01:02:34.240 Thank you once again, Robert, for making time to share your knowledge and expertise. I hope we get a chance to talk again in this kind of depth about art materials. Fumed silica? Refractive indices? I love it all. And thank you for listening to Dabble On. I'm glad you're there. If there is a topic you would like to hear a deep dive about, let me know. You can email me ideas at dabalon at gmail.com. Also rate this podcast on iTunes, make a donation on the website, and tell friends and family. And go check out the 3-inch Gamblin' Varnish Brushes. They're nice. ♪