Question: Drying Time in Oil Paint

Pedram F., an artist who works in Sweden, asks: "Heya James! Big fan and silent watcher of your posts and blog here! I'm going to break the silence tho' this time around because I have been watching your latest video on the Rise of Tyrannosaurus that I bought recently. It's a really simple question that wasn't really touched on, except maybe only hinted at in the video, but I wonder how long it takes for your painting to dry in between the stages/layers. Do you always wait for touch dry before moving on? Since you are using different dryers or mediums that shorten the drying time, it would be interesting to know how long you wait in between sessions. That is, from the moment you put down the paint brush to finishing it."

Hi, Pedram,
Great question! Thanks for asking. When I'm painting on a deadline assignment, I usually want the section that I'm working on to stay workable for a couple of hours. A few hours is usually plenty of time to accomplish any kind of blending or gradation. I typically want it to be dry to the touch by the next morning.

When there's time for slow drying
If I really need more than one day for a given passage—such as a big cloudy sky or a portrait with a lot of edge work—I might use a more normal painting medium (such as damar varnish + stand oil + gum turpentine), or no medium at all. In that case, I make sure to paint that passage early enough in the deadline cycle so that it will have time to dry to the touch in a natural way before I need to deliver the painting.

I have to be careful about thick impastos of titanium white or the cadmium colors, because they dry slowly. The last parts to dry are often the highlights. Those might take days or even weeks to dry.

This particular assignment allowed six weeks from first call to delivery. More than half of that time was taken with research, sketches, and approvals—which is typical for a scientific or historical illustration. As a result, the final paintings had to be done in the last two weeks. Most magazine deadlines allow a few weeks to a month start to finish, but I am sometimes called in on much shorter deadlines.

Eight strategies to speed up drying

1. Working thinly is a third way to get oil paint to dry quickly. I use Winsor and Newton's Alkyd mediumor Gamblin's Galkyd medium if I need medium at all. If the paint is reasonably thin, it will be set up by the next day.

2. Pre-texturing is the method I show in the video to achieve thick paint with impastos, while still getting the paint to dry quickly. The thin oil paint is applied over the surface of the dried acrylic underpainting textures. The oil layer dries overnight, but because of the underpainting textures, it looks like a thick impasto.

3. Another method is a heated drying box used at night between painting sessions. A drying box is an enclosed fireproof volume built to contain the painting, together with some heating element, such as an incandescent bulb.

4. If you don't want to build a box, you can use a light bulb in a reflector clamp lamp to speed the drying. If the heat is coming just from one side, there's a danger of warping the board or damaging the surface of the painting.

5. One solution for such thick paint is the use of chemical accelerators. If I think I might use thick passages of white or cadmiums, I might use just a drop or two of cobalt drier mixed with a palette knife into the blob of white on the palette. As I'm sure you know, these driers should be used sparingly, as they can weaken the paint emulsion and change the color if one uses too much of them. I rarely resort to them, but if I need them, they can be a lifesaver.

6. Another tip that you'll recall from the video is that I can save a day by doing a casein underpainting. Casein is a well established underpainting medium for oils, and the painting can be taken to any stage in that medium with the oil used only where necessary.

7. Sometimes the oil paint just isn't dry the night before shipment or hand-delivery. In that case, I build a gapped box, with cardboard shims around the outer edges, so that the cardboard of the container is not touching paint surface. I also would then put a note in the box to let the art director know that there might be some wet paint.

8. A final expedient is for the artist to photograph the wet painting instead of shipping it to the client. As long as the copy work is done to a standard acceptable to the client, this can save everyone a lot of effort, expense, and time, and then it doesn't matter if the painting is wet. If the lighting set-up is good, the new cameras such as the Canon Digital Rebel can shoot excellent high resolution files that rival what a lab could deliver. Here's a blog post explaining how I typically photograph paintings, and here are two other blog posts by Dan Dos Santos and David Palumbo explaining how they do it.

Hope that answers your question, Pedram. And in case anyone else wonders: I haven't experimented much with water-soluble oils, tubed alkyd paints, or acrylics, mainly because I've got my hands full with oil, casein, gouache, and watercolor. I'm sure they have wonderful properties, but I just haven't had a chance to try them out.