I don’t care for odorless mineral spirits (or turpentine); my studio is not as well-ventilated as I would like, and I worry about inhaling the stuff. So I simply use M. Graham walnut oil as a medium, to clean brushes between strokes, and to clean up after painting. Walnut oil is great – except that it’s not really appropriate for thinning paint for an underpainting or sketch, as ideally one wants that first layer to be “lean,” not “fat,” and oils are “fat.”
The traditional answer is to thin the drawing (or first layer of an underpainting) with OMS or turpentine, but those aren’t an option for me. Paint out of the tube works okay, but it doesn’t dry fast enough, and it pollutes or show through later layers. A thin layer of water-miscible oils, thinned with water, is a conceivable solution for a drawing/underpainting, as is a layer of water-thinned acrylics or even water-thinned casein. Drawing lightly with a light or gray colored (wax or oil, not graphite) pencil is my current approach. But I’m wondering there are any other solutions. Anyone have suggestions?
Thanks in advance!