I have done some outdoor painting with these paints. I quickly learned that if you use water as a solvent they seize up and get tacky quickly in the heat, so I use water only for brush washing outdoors. However, I have recently found a new use for them, as the oil paint component of a methylcellulose-oil emulsion, and for that type of painting, their ability to dissolve in water matters. I wanted to compare brands and see which is best for that, so I finally got around to making color charts of the water miscible oils I have: mostly Duo Aquas, about 6 Daniel Smith (DS), and 3 Cobra, plus a lot of Artisans that I didn’t test since I mostly have just not liked that brand, and it wasn’t at all reliable with water. I hoped to decide what brand to settle on, since it’s probably best practice to not mix them thanks to the proprietary chemistry.
I took a look at water solubility, pigment load, and handling as much as possible with small swatches.
I have been enjoying tempera-oil emulsion painting, also known as tempera grassa. I recently did a painting with tubed egg tempera, which is a lean oil-in-water emulsion, and decided I need to research the ground and support, since it didn’t adhere very well to an acrylic primed canvas. Choice of ground and support depends on the relative proportion of oil and water in the emulsion, ranging from traditional gesso on panel for pure egg tempera to oil-primed stretched canvas for a heavily oil-biased emulsion. Painting on panels is generally much more durable than on stretched canvas. The almost universal recommendation for egg tempera is to make your own panels with rabbit skin glue gesso, but I don’t want to work with large quantities of powder if I can help it, so am looking at other options.
A few things I have tried with tubed egg tempera and somewhat fatter methylcellulose (MC) emulsions are Arches oil paper and Multimedia Artboard. Both had good points and problems. Multimedia board seemed too slick for tubed egg tempera; it worked much better for MC paint. Unfortunately, it is brittle and very prone to cracked corners if not mounted on something. Arches worked well with egg tempera and MC, but buckled if the paint was thinned with much water. Paint could be lifted off both surfaces, even after a day, but I’m using oil in the mix so that’s expected.