ALTHOUGH I love thick painting one of the disadvantages is that once the paint is dry it is quite difficult to make changes. I’ve struggled with a variety of techniques and all of them fall short of painting a scene right in the first place. But if the painting has enough virtues you owe it to your work to learn to salvage a weak painting as best you can.
I have tried many times to simply paint over the roughly painted texture. But I’ve found this to be nearly impossible. If you try to paint right over a highly textured area the corrected area will have a dry, leathery, chalky quality. SoI have to scrape the dried paint until it is reasonably smooth. But you don’t need to scrape down to the canvas. A slight texture is not altogether undesirable. In fact, if you scrape too much you will get a surface that is too smooth. Scrape off the high points and be sure there is no roughness.
To scrape the canvas I use a variety of ceramic tools. They are too dull as they are right out of the package but I sharpen them with a common sharpening stone. I then strop them by applying a drop of chromium oxide green oil paint onto an old piece of leather. I use the tongue from an old boot. Make sure it is real chromium green oil paint and not a hue. The chromium oxide in the paint is identical to stoping compound and you can get a finely honed edge which will give you the control you need to very carefully scrape dried paint from the canvas. Be careful though, by using the chromium oxide green as a strapping compound the ceramic tool will be sharper than you might expect.
After I scrape the canvas smooth I brush a thick, transparent medium onto the canvas. Some artists call this “oiling up” or painting into a “couch” ( a French word that is pronounced KOOSH).
I then paint into this layer of oil using paint that I have slightly diluted with a small amount linseed oil or walnut oil. This additional oil helps the paint to go on with smooth, facile strokes. Otherwise the paint can be too sticky and simply push the layer of oil around on the canvas. After you get a certain amount of paint built up into this layer of oil you can begin to add as much textured paint as you desire.
Although this technique seems ideal it has its problems and have never been fully satisfied and try to keep its use to a minimum. It has however saved many paintings that otherwise would be suitable only for the trash Heap. When it is well executed it is almost impossible to detect its implementation. I suspect that with the passing years I will become more adept at the technique and will enjoy more success.