Although acrylics dispersion grounds (incorrectly named "acrylic gesso" by the industry) are suitable for oil paintings on canvas, but they are not suitable for applying over an existing oil painting. Acrylic dispersion grounds may not adhere well to an existing painting on canvas. These grounds are also very flexible -- far more flexible than an aging oil painting -- and for this reason may not be the most suitable choice as a ground for oil painting in the long term.

The best grounds for oil paintings on canvas are oil grounds. Lead oil grounds, in particular, provide the best type of oil ground, although alkyd grounds can also serve this purpose, if you do not want to use a primer containing lead.

These grounds are typically formulated to provide good coverage, limited absorbency and penetration, flexibility and holdout. You can cover an existing painting with lead oil ground, but you should first reduce the texture of the existing painting (if any) and be sure that the painting is thoroughly dry before applying the ground.

Lightly rub the surface of the painting with pumice stone or sand paper and wipe it clean of any dust. Apply at least two thin coatings of the oil ground over the painting. Allow each coat to dry and then wait some time to be sure the ground has completely dried hard.