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Anthony, one of the major problems discussing methods and materials is the definition of terms. "Gesso" is an Italian word synonymous with "gypsum". For well over 500 years, the term has meant a mixture of hide glue, gypsum and calcium carbonate in varying proportions depending on its intended end-use.
With the advent of acrylic co-polymers, "acrylic gesso", a mixture of marble dust and acrylic resins, has come into common use as a quick, easy and inexpensive way to prepare raw canvas for oil painting. A broad array of water-soluble coatings employing similar chemistry have supplanted "oil base" paints for home maintenance. Vinyls, vinyl-acrylics, urethanes and other plastic resins have come to be known as "latex" paints."Latex" tile and carpet adhesives are "spin-off" products which capitalize on the adhesive qualities of these compounds. Most contain a percentage of clay. Of course, the original definition of "latex" refers to the milky sap exuded by certain plants used in making natural rubber products. "Paint" and "latex" are only compatible terms when descrbing the rubbery flexibility of these plastic paints and adhesive films.
Back to oil painting supports, paintings were initially made exclusively on wooden panels. "Real" gesso was the preferred ground preparation for painting, as it provides desired surface character such as silky smoothness, while rectifying defects in the wooden panel such as glue joints, grain and other imperfections.
The weight of wooden panels being a decidedly limiting factor in the size of such paintings, very soon fabrics (hemp, linen) stretched over wooden frameworks provided the solution to making paintings of considerable scale with a minimum of weight. Of course, this remains true today.
The brittleness of gesso contraindicates its use over a flexible support such as fabric stretched over a frame. Consequently, the acceptable method is to prepare the surface of canvas with an oil ground, usually lead white, often extended with calcium carbonate, clays, and other inert fillers which provide specific surface characteristics and degrees of absorbency.
To stop the raw fabric from absorbing the oil binder in the ground, the canvas is first sized with hide glue. This has been the basic method for preparing sound and durable supports for painting in oils for over 500 years. The relative permanence of this method is attested to by the many paintings from the 16th century and earlier which survive in reasonable states of preservation.
A problem arises in "marrying" modern water-reducible plastics with oil paints. The two materials are essentially incompatible. Theoretically, an acrylic ground remains permanently flexible under layers of oil paint which will enevitably become brittle, a violation of the "fat over lean" principle for sound technique in oil painting.
In addition, the smoother a "latex" underlayment is, the more likely it is to cause adhesion problems for over-paint layers in oils. Acrylic "gesso" is workable only to the extent its abrasive filler content provides absorbency and a mechanical "key" for oil paint to grip.
Finally, as far as the length of time necessary for a ground preparation to be laid-by before painting, with "real" gesso as with modern "latex" the only criterion would be whether the water content has fully evaporated before applying oil paints.
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