Thanks for posting your test results.

You don’t say how thick the strips of paint are. They look pretty thin but I can’t be sure from the photo. I use at least a half a teaspoon of clove oil in a small cup with some cotton in it inside my totally air tight palette box and the nuts of all colors except Burnt Umber stay wet a lot longer than your test. I am assuming that you used thin layers which would dry significantly faster than a thick nut.

I would like to see the same test but with a good sized nut of wet paint rather than what appears to be fairly thin strokes of paint.

Thanks for the information Richard, this is the kind of stuff we seem to not have enough of on the forums recently. Admittedly, I have been lackluster at doing such tests and posting results, far too busy with production and skill building to concern myself with new materials like clove oil at the moment. Super interesting results though, and good testing method, practically applicable result information.

If it’s okay, I’ll add my bit:

Totally unscientific, in no way meant to be a scientific experiment, but possibly informative for some people anyway.
Full disclosure: I do not know what I’m doing.

A year or so ago I made me a small collection of dabs of my standard paints into a small relatively tight closing container. Just enough paint for probably 1, maybe 2, 4×6″ paintings. I enjoy plein air, but simply cannot carry much stuff. In with the paint I added a bit of paper towel, maybe 1/2” square and a few drops of clove oil. I used it once, then placed it into a plastic zip type baggie, and stuck it into the freezer. I didn’t get back to it for a long time.
The paint generally stayed in usable condition for several months. But I keep my working palette in the freezer anyway, and most paint stays good for quite a while, depending on the size of the dab itself, and if it is a slow drier or not. ie, burnt umber will get hard overnight-I rarely leave any on the glass.
So maybe it wasn’t just the clove oil at work, but also the freezer and the air-tightness of the container, too…

FWIW, the paint on my little palette was right out of the tubes, and what I would generally expect to use for landscape here in the desert: Cad yellow lt, yellow ochre, Cad red lt, aliz crimson, ultramarine and Prussian blues, ivory black, burnt sienna & umber, indian red, chrome oxide green, white. These dabs were about the size of 2 pencil tip erasers, so not large.

This little box in it’s baggie stayed in the freezer several months. I took it out a few weeks ago to use the paint if it was still usable. If I remember correctly, most of it was, and I did use it without problems. There were some with skins, I do not remember which. But the lumps were so small, and time in freezer was so long, I was surprised any of it was still in good condition. I did use it for a study, don’t know I’d use it anything more than a study.

I added the clove oil specifically to retard drying time for “shelf life”, not knowing how soon I would be able to get out.

Contumacious:

I seal my paintings in a box between sessions, and although the box would be bigger I thought the drying times might be only a little less compared to these tests.

The test makes more sense now. I didn’t catch the fact that you store your unfinished paintings in a container – I only read it as a palette storage test – Doh!

Storage the palette in the refrigerator in an air tight container with some clove oil on a cotton ball extends the open time quite a bit more than just clove oil alone. The same would possibly be true for a painting in progress, but finding the space for a stack of paintings could be problematic. Maybe a free or really cheap refrigerator or freezer off of Craig’s list to keep in the garage just for art?

For me, the freezer keeps the palette wet even longer than the refrigerator, but you do have to wait for it to thaw before use. Some day I may do a palette test in the refrigerator and freezer with and without clove oil just for fun.