Golden's Open Formula acrylics

I jumped on Golden's Open Formula acrylics as soon as I heard about them, thinking they would provide a great medium for revision in the studio, since working on field paintings in the studio can be tricky with acrylics.

That's because the subject is no longer before me and my only reference, the painting itself, is gone once I paint over parts of it. Sometimes by the time I step back and decide I don't like the new version, it's dry.

I thought the longer drying period of Open acrylics would allow me to wipe off areas I didn't like, retaining what was underneath. What I found, however, was that the drying period was variable. Sometimes the paint would feel dry after half an hour, sometimes after ten minutes. In either case, when I tried to work over a "dry" surface I found the layer underneath dissolved into new wet paint.

The huge advantage of acrylic for me is that it dries quickly and absolutely, and subsequent layers can be laid on with absolute assurance. In a moment or two the new layer is dry and can be revised in turn. But if you don't like a stroke, you can immediately wipe it off with a damp cloth and reveal the previous layer.

Using Open acrylics that assurance is gone. It's hard to know how long to wait before the previous layer is completely dry, but it might be hours or days.

A system I like much better is to use Golden Heavy Body acrylics outdoors with water as a medium. When revising inside, use glazing medium instead of water to slow the drying time slightly. Once the paint feels dry, it IS dry for practical purposes.