If you are making a trace of a conceptual art work, you may consider the object you make an homage to process. (Happy 100th to Dada)
If you intend to make an oil painting, the BACK of painting should not look like this one. (Image 1)
Allowing oil binder to saturate the fabric compromises quality by destabilizing the pigment-to-oil ratio. When too much binder leaches out of the paint, pigment can dust off the surface until the painting looks more stained than painted. Mars Black, in particular, is a lean paint which means it has less binder - a high pigment-to-oil ratio. (Images 2 & 3 - under bound painting. Image 4 - thick well bound painting.)
Linseed oil is the traditional binder for artists’ colors because it is easily available and dries to a firm film within a reasonable time frame (5 - 7 days). When made into paint, linseed oil surrounds particles of pigments. Colored pigments cohere with potential to flow. When the oil in paint sinks into fabric, the pigment is under bound on the surface. The resulting surface is matte and can look crumbly.
When artists spread out a paint layer and expose it to oxygen, the linseed oil binder begins to form into layers. Initially, layers dry by absorbing oxygen and expanding. When paint films release oxygen in the next phase of drying, the paint film shrinks. Depending on thickness of the paint layers and additives, the interior layers may take years to dry completely. All the while through all the years drying paint on an unprimed canvas continues to pull fabric threads apart as it shrink. When primed, most of the stress on an aging traditional oil painting is on the size/ground layers not the fabric.
While the mechanics of old oil paintings are fascinating, the issue for painters today is: how long do you expect your painting to last? how matte do you want your paintings to be?
If you paint on unprimed fabric, your paintings will be matte unless you add resin and varnish.
If you paint on acrylic gesso, the question is how much. You really need to apply three to five solid coats of top quality gesso. Takes a lot of gesso to do the work of two thin coats of oil ground. Using oil ground is a hassle in my opinion because of the size. The size isolates the oil ground from the fabric.
Priming the surface is probably the only part of contemporary painting that reveals to us what painters of the past experienced. Most of their painting layers required isolating varnishes. Most ingredients were reactive. Pigments were poisonous. Lead had to be isolated from Vermillion so it didn’t turn black. Oil binders were contaminated with weed seed and dried very slowly. Animal glues had to be prepared from skins! Nothing was available at the art supply store.
If you want to use oil ground and stretch your own canvases, apply PVA size before you stretch because PVA slackens fabric.
If you paint on panel, do what you want.