FYI in case it proves useful for reference
I have just completed my first proper test of clove oil for extending oil paint drying time. Although I have used it for a few years I’ve never tested it out properly with different pigments.
For this test I mixed several of my core paints I use (cheap, low chroma, high opacity) with walnut oil until they took on a slippery quality. I then applied each mix to two separate sheets of PET-G with a W&N clear acrylic gesso ground.
Each sheet was stored in an A4 sided clear plastic folder and sealed (so probably not air tight, but not open to freely moving air). They were stored side by side in a dark (but not totally light free) house temperature environment. Each night I would open both boxes and test if the paint had dried by drawing down a vertical line with the use of a rubber shaper tool.
One sheet was left as it is, while the other had a cotton wool pad placed inside and two drops of clove oil were added to it each night. So no clove oil was added to the paint itself and the paints on each sheet came from the same mix. I then recorded once a day over a period of 14 days for each sample when they had touch dried.
The results were surprising.. and interesting. I didn’t expect to see much variation in drying times in the same pigment between brands. If anything I expected that the stiffer brands which had more walnut oil added might take longer to dry.
Instead I found the complete opposite! The stiffer paints seemed to not have their drying time extended very much at all by the clove. I am not sure if this is due to the the presence of driers, or waxs/aluminium stearate in the paint to add body. Or maybe it’s for another reason as yet unknown?
I though I would share the results as they might prove useful to others. Next I want to examine the difference with clove oil present in the actual paint, as well as not replenishing the clove oil drops each day.
Photo of the folders used and test surfaces:
clove_oil_test1.jpg
Final results, stopped after 14 days.
Clove_oil_test_results1.PNG
Hi Matthew,
The oil was 100% clove bud oil from Holland & Barrett (Health food shop here in the UK). The pigments used were PBk11 for the mars blacks, PBk6 for the lamp black, PW6/PW4 for the whites, PR101 for the red iron oxides, PY42 for the yellow ochre and PBr24 for the naples yellow deep.
So you can see that the PBk11 with clove oil vapours dried in 14+, 3, or only 1 day depending on the brand..
Thanks, this is very interesting. It might be useful to include the source of essential oil, because eugenol content is not standardized in this material (the antioxidant component) and can vary by what might be a significant amount by brand.
Also, rather than relying on stiffness of the paint to predict the influence of clove vapor on drying, I would suggest documenting the specific pigment content of the colors. Pigments have a lot to do with drying rate.
An additional factor to consider is whether, if the clove is preventing skinning, whether that is actually helping through-drying in some colors. Industrial enamels include anti-skinning agents to help support drying, because a paint skin can (as I understand it) isolate the interior and bottom of the film. There is a spray that is sold to speed drying in artists’ oil paints, and I know it contains an anti-skinning agent.