There are a number of oil painting mediums based on synthetic substances called alkyds. Alkyds can also be used as a binder for paints, but I’m specifically talking about mediums made for mixing with regular oil paint. These include Liquin, Galkyd, Neo-Meglip, and a number of other products.
Although they are popular, I don’t use them, for several reasons.
- I don’t think they’ve been around long enough to prove themselves. While the first popular alkyd medium, Liquin from Winsor Newton, has been around for decades, it has apparently been reformulated several times. So we don’t know what modern alkyds do to paintings, exactly.
- I have heard a few (not many, but a few) reports of delamination in multi-layer painting that artists have blamed on alkyds. It appears that under some circumstances, one layer of oil paint containing alkyd medium may not reliably adhere to another layer of paint containing alkyd medium. This issue is probably not a concern for for single-layer alla prima painting. If you do choose to use alkyd mediums in multi-layer painting, my recommendation is to reconsider. But if you do choose to willfully ignore my excellent advice, you should at least scuff the dried paint in between layers with a kitchen scrubee pad to encourage mechanical adhesion.
- I like using traditional painting materials. I use some modern pigments, but I don’t like using modern binders or mediums. That’s just me.
- I don’t particularly like the way the couple of alkyd mediums I’ve tried handled.
- I hate the way they smell. It’s not a strong odor, but it’s insidious. Compared to, say, Canada balsam and oil of spike (one of the best smells in the world), alkyds smell like a distant petroleum refinery.
- Used excessively, alkyd mediums can cause yellowing. So do many of the more traditional mediums, of course, but alkyds do not have “don’t discolor” as an advantage. As with any additive to oil paint, only a very small amount of alkyd medium should be used.
- It’s hard to say whether alkyds are “fat” or “lean.” Fat mediums dry slowly and are relatively flexible. Lean mediums dry quickly and are more rigid. Alkyds dry quickly and are flexible. In multiple-layer painting, the rapid drying of alkyds could cause problems when used with other, slower-drying, fat mediums. If you use alkyd mediums in multi-layer painting, my recommendation is to use the same medium formulation throughout the painting, simply using a bit more from one layer to the next. Don’t use other mediums as you go.
- Some artists seem to use alkyd mediums mainly for their property of causing the paint to dry more quickly. If that’s what you are looking for, there are a number of more technically sound methods.
Although they are cheap and easily accessible, I don’t see any particular advantage that alkyd mediums have that might balance out these concerns. If you are using mediums correctly, the amount that goes into any painting is so small that the expense of even a relatively expensive bottle of medium is miniscule. I admit that I’m a bit of a painting materials snob, but I’m OK with that. In my view, alkyd mediums are the fast food of oil painting. They are cheap and you can get them almost anywhere, but they aren’t very good for you.
I have heard of some artists who become so enamored of alkyds that they use them as a medium and also as a final varnish. That’s an especially bad idea, as most of the companies that make alkyd mediums will tell you. If used as a varnish, alkyd mediums may cause yellowing. Also, it will not later be possible to remove the varnish when cleaning the picture, which is a critical property for a varnish to have.
1/31/07: rewrote with some additional information.