Here’s where the “White Shirt” painting is at. What I’ve done is finish initial rendering of each area of the shirt. I found that the hues were uneven—I am still learning to manage near-neutrals across relatively large areas of a painting. What I tried was to glaze transparent yellow oxide across bluer shadow areas, which evened out hues somewhat, but the overall painting was unconvincingly yellow-orange. I had also over-rendered much of the shirt, with too broad a range in value between darks and lights.

This was a perfect time to apply a velatura.

Taking a hint from Tad Spurgeon, I mixed up a batch of putty. This was calcite (ground marble dust) mulled with walnut oil and a bit of stand oil. The resulting mixture was a dull grey with the consistency of, well, oil paint. Putty is a medium used to increase the transparency of paint, since the calcite is essentially invisible in an oil vehicle. This is better than adding a lot of oil or resin, as the calcite/oil mixture is as strong and as resistant to discoloration as oil paint.

I mixed the putty with lead white (Doak’s flake 1C) in approximately equal amounts. Then I added a very small amount of neutral gray paint (ivory black and burnt umber) which I had previously tubed. I now had a very light gray, relatively translucent mixture.

I oiled out the surface of the painting with a thin layer of walnut oil, which is very slippery and less yellowing than linseed. I applied the gray mixture to the surface. Initially, it looked awful—my careful painting was covered with flat gray. With a stiff bristle flat, I started working at adjusting the thickness of the velatura layer, pulling the underpainting out. I found that it was effective to moisten the brush with a bit of walnut oil. It took awhile, but eventually the underpainting began to show through, with the value range compressed toward the gray value of the velatura and the hue pulled toward neutral.

It needs a bit of work once the velatura layer has dried to restate a few highlights and dark accents, but overall this was a successful exercise.

I love the M. Graham watercolors, so I am going to start there, but, I wonder: Can I use linseed oil with them as a brush cleaner without degrading the quality of the walnut oil? (Linseed is SO much more cost effective.)

Thanks, Alex. I’m not aware of any technical reason not to mix linseed with M. Graham oil paints (which are ground in walnut oil). M. Graham would much prefer that you buy oil from them, but inexpensive linseed will work just as well and is exactly as natural and nontoxic (don’t buy boiled oil or other hardware store linseed oil).

In fact, two of my favorite paint makers—Robert Doak & Associates and Blue Ridge Artist Materials—grind their paints in a linseed/walnut blend. You might want to check them out. M. Graham is of mid-range quality while theirs is high-end, but not all that much more expensive. All three brands are extremely smooth and brushable. You could mix paint from all of these brands together without any problems.

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