[Virgil Elliott]

The jury is still out on whether or not acrylic emulsion grounds (called "acrylic gesso") will prove suitable for oil paintings on stretched canvas in the long run, but acrylic paints do not have enough tooth to provide good adhesion for oil paints applied over them. They will appear to work all right for awhile, but will be prone to delaminating in later years, after the oil paint layer loses some of its flexibility.

As part of my selective editing policy of destroying my worst pictures, I once tore a painting in half that had acrylic underpainting overpainted in oils, and as I ripped the canvas, the oil paint layer cleanly separated from the acrylic underpainting. It was obviously poorly adhered, and would have come off at some point whether I'd torn the canvas or not. This painting was seven years old at the time. Needless to say, I never again underpainted in acrylic. Some extremely knowledgeable conservators and conservation scientists in my acquaintance have expressed concerns that acrylic grounds (primers, acrylic "gesso") may also prove problematic in the long run on oil paintings done on stretched canvas. On panel, it may prove to be all right, but it is too early to say with certainty at this point. I have also had a demonstration painting delaminate at the interface between the acrylic ground and the layer of oil ground I had applied over it some months before, which was enough to convince me to stick with oil grounds. I also decided to stop painting anything important to me on stretched canvas. I now mount my canvas on a rigid panel.