Month after month, this is the single most popular post on this site. It seems that lots of people are using search engines to answer this question.

Before I do, I should point out that Mr. Mathis is, so far as I can tell, a professional artist who supports himself with his very good paintings. I, by contrast, am no more than a wannabee. On that basis, he has and deserves far more credibility than I. He is, however, commenting on the practices of another professional artist of at least equal stature (and fairly similar artistic style). It is certainly true that some professional artists throughout history have used ill-advised materials and painting methods. In any event, either Mr. Whitaker is right or Mr. Mathis is right on any of these issues (or they are both wrong) and I, lowly hobbyist that I am, will attempt to compare one to the other against my own limited experience.

Mathis’ concerns are based on what he has gleaned from doing internet searches and by that means finding recommendations that Whitaker has made on various internet fora regarding appropriate painting practices. Before starting on his primary criticism (regarding Whitaker’s recommended painting ground) Mathis first objects to Whitaker’s recommendation that Maroger’s medium is good to use and should be mixed with paint in a ratio of about 25% medium to 75% paint. In case you are not aware, this medium is from a recipe originally conceived by an artist and painting conservator named Jacques Maroger. It consists of thick mastic varnish (made with turpentine) mixed with black oil (which is linseed oil cooked with litharge, a lead compound). There are many claims out there regarding Maroger’s medium and its effects. I have heard both that Maroger’s own paintings are in horrible shape (turned black) and that they are so perfect that they look like they were painted yesterday. I have heard the same of his student’s paintings. I have not seen any of them. Other artists make claims about Maroger that are all over the map. Most conservators seem to condemn it. At least one technical conservation paper looked at some of his student’s paintings and found that they had deteriorated rapidly (although some of his students seemed to like the stuff so much that it seems as if they painted with Maroger medium into which a tiny bit of actual paint had been mixed).

My general take on the matter is this. I agree that 25% of any medium is way too much. Generally, I prefer to use just oil paint and perhaps just a touch of medium here and there. There are a number of products that are called “Maroger’s medium” and I am sure that they differ in their properties, so a blanket condemnation is probably not warranted. The one kind that I’ve tried seemed to slightly improve the handling characteristics of the paint, but not in any dramatic way. I don’t use it any more, myself, in part because of all the hysteria (which may be based on some truth) and in part because there are mediums I like better. Overall, however, I am neutral on the issue of Maroger’s when used very judiciously.

Mathis next condemns Whitaker’s recommended practice of wet sanding. This is a procedure that I myself use and recommend. He objects that any water on dried oil paint will cause all sorts of problems, such as buckling or delamination. Huh? Sitting a painting in water is of course a bad idea. Spreading a little water on a dried surface, sanding for two minutes, and then drying it off is unlikely to cause any sort of harm. Of course one should make sure that the surface is completely dry before painting on it. Water has no magical power to damage a painting. Extended exposure causes problems. Light wet sanding improves the tooth of the surface and improves the mechanical bond between layers. That will likely decrease the chance of problems, not increase it. And if you do sand, wet sanding instead of dry sanding greatly decreases the chance that you will breathe pigment dust. Mathis also objects to the idea that one should try for a smooth surface when painting. He thinks that such a desire is “fussy to the extreme.” I think that depends on the kind of painting you’re trying to make. Certainly a van der Weyden painting would loose much of its power without a smooth surface. I don’t usually worry about a bit of texture in my paintings, but I don’t think that painters who want a smooth surface should be condemned for that.

Next Mathis gets to the heart of his objection to Whitaker’s painting recommendations: he opposes the use of ABS (acrylonitrile butadiene styrene) as a painting surface. Firstly, he notes that ABS dust is very poisonous and that Whitaker suggests sanding it, which, Mathis says, is extremely dangerous. I’m not a materials scientist or toxicologist. No one should take my advice (or Whitaker’s or Mathis’) with regard to their health. The limited research I’ve done indicates that sanding ABS is something that should be done with a dust mask and that the dust should be thoroughly cleaned up afterwards. So far as I can tell, we’re not talking Chernobyl here. However, if you do choose to work with ABS, please do your own research and follow appropriate safety precautions. Err on the side of caution.

Throughout this section of his essay, Mathis really starts to hyperventilate. He quickly moves beyond art materials and ABS to a broad condemnation of all plastics in Western society. They are poisonous and evil.

Mathis wants us to be wary of what art materials manufacturers try to sell us and be aware of their profit motive. That’s perfectly valid; there is a long history of artists being taken in by shysters. He cites a web link from Greenpeace that warns of all the dangers that plastics present. Mathis appears to have lots of skepticism of the motives of capitalists but none at all for those of anti-capitalists. The people who run Greenpeace have their own agenda and their own incentives. The more they can get people upset about threats posed by various materials, the more donations they get and the more political clout they have. All sides have motives that can be questioned. If you treat one version of any story like this as unimpeachable, you may find yourself ranting in exactly the way Mathis does here. ABS may be as dangerous as he says. But I tend to be careful about one-sided stories such as the kind that either transnational corporations or radical international environmentalist organizations try to sell to us.

In any event, I don’t think that the choice by an artist to use or not use ABS has much to do with the morality of modern Western civilization. Which, I might point out, generates vast amounts of surplus wealth that allows hundreds of thousands of people to work as artists instead of doing backbreaking manual farm labor to feed themselves. I find that to be a good thing.

If Bill Whitaker is recommending that people sand ABS without first taking appropriate precautions, then he’s giving bad advice. Mathis also objects, however, to painting on ABS after it has been prepared as a painting surface. I’ve done exactly one painting on ABS. I was sent the panel as a free sample by the folks at www.realgesso.com (who, I suspect, use appropriate precautions in their manufacturing process). The panel was already prepared and I did no sanding. I found it to be a very pleasant surface to paint upon. It took the paint well without being sticky or “chattery.” Overall, however, I didn’t find it to be superior to either traditional gesso or lead primer. The panels are expensive, so I prefer to make mine myself with materials I understand a bit better than ABS. Mathis recommends lead white, and so do I.

He also objects to ABS on the grounds that there is no reason to suppose that paint will reliably adhere to it. When I used it, the paint seemed to stick just fine. That painting is less than a year old, so there is no telling what the long-term prospects are for permanence. My overall philosophy with painting materials is that I want to work with stuff that other people first experimented with at least a generation ago, so that any problems will have come to light. I appreciate the brave sacrifice of those who use ABS panels, alkyd mediums, and other materials of questionable longevity for painting applications. 100 years from now, artists will have an excellent idea of whether they were a good idea. For now, we don’t actually know.

For that reason, I’ll generally skip ABS. While I don’t have the philosophical objections that Mathis does, I don’t see that ABS solves any problem that I actually have.

Some painters are fine with letting paintings dry for days or even weeks. They work on more than one piece at a time and come back to each one when it’s ready. But sometimes you want stay with one piece, working every day. Here are some ways to control the rate at which oil paintings dry:

• Paint in thin layers (like the thickness of a normal coat of house paint).
• Avoid slow-drying pigments like titanium white and ivory black. Use fast-drying pigments like lead white and burnt umber.
• Use paints ground in linseed oil. Avoid paints made with slow-drying oils like safflower and poppy. Also avoid walnut oil, which dries faster than safflower or poppy, but slower than linseed.
• Use a lean lead-containing medium such as Maroger’s (in very small amounts).
• Add a bit of solvent to the first layer. Sprits of turpentine and oil of spike interact chemically with the paint, causing it to take up oxygen more rapidly and dry faster. Mineral spirits do not react in any significant way, but all solvents will make the paint layer thinner, which does make paint dry faster. Don’t add so much solvent to paint that it becomes washy or watery. Just add a little bit.
• Paint on a panel primed with glue-chalk gesso. The first layer will have some oil absorbed by the gesso, so the paint dries more quickly.
• Add small amounts of metallic driers to the paint. I prefer lead napthenate. I add one tiny drop (from a toothpick) per blob of paint on the palette and mix thoroughly. Excessive use of driers will damage the paint film, but that much should not be any problem. I generally add driers only to slow-drying pigments.
• Paint on a copper panel. The first layer of your painting will dry more quickly.

Some painters also use alkyd mediums such as Liquin, Neo-Meglip, and Galkyd. I don’t use alkyd mediums and I don’t recommend them. However, they do make oil paint dry faster.

When I need to, I can get oil paint dry in a day, so I don’t usually have to wait for a layer to dry before I can paint over it. Sometimes, I choose to use a medium that makes the paint dry more slowly, or I use a slow-drying pigment like titanium white. But when I do that, I know that the paint will need extra time to dry. My glazing medium (a 50/50 mixture of black oil and Venice turpentine) is somewhat slow-drying, so glazes usually take two or three days to dry.

It’s also the case that I often complete one section of a painting at a time. That way, it doesn’t matter whether yesterday’s paint is dry, because today I’m working on a different part of the picture.

Updates

Update 22 February 2007: In a comment on this post, Louis R. Velasquez pointed out to me that some solvents do cause oil paints to dry more quickly via chemical action. I have corrected the information in this post. I am grateful to Louis for pointing out my error.

Update 19 February 2008: Added painting on copper panels as another way to make oil paint dry more quickly.

Related post

• Oil painting without solvents