Oil Painting Techniques That Last: A Painter's Guide to Wet-on-Wet, Glazing, and Fat Over Lean

♦ ♦ ♦ JUNE 16, 2026 | 4 MIN READ Oil Painting Techniques That Last: A Painter's Guide to Wet-on-Wet, Glazing, and Fat Over Lean At a Glance The oil painting techniques worth knowing come down to three decisions a painter makes at the bench: how wet the paint is when it meets other paint (wet-on-wet), how light passes through it (glazing), and how the layers are stacked so the picture does not crack (fat over lean). The last one is the difference between a painting that ages flat and one that grows a web of cracks. A jar of brushes, a slab of glass for a palette, and a painting that has been wet for three days because the artist will not let a layer dry before they are sure of it. That is most oil studios, and it is where every technique below actually lives. Forget the long lists of named methods for a moment. Oil painting technique s are really just a handful of decisions about time, transparency, and order, and a working painter feels all three in the hand before they ever name them. Wet-on-wet (alla prima): the oil painting technique done in one session Wet-on-wet, also called alla prima, means working into paint that is still wet, finishing the picture in a single session before anything dries. The colours blend on the canvas itself rather than on the palette, so the marks stay alive and a little unpredictable. It is the technique behind most plein-air painting and most portraits done from life, because the painter has to commit. What a collector is looking at, with a wet-on-wet oil, is a surface of decisions made once and left standing. There are no buried layers, no second-guessing sealed under varnish. The light sits on top of the paint, not down inside it. The risk the painter is managing is mud: push wet complementary colours together one stroke too many and the whole passage goes grey. So a clean, luminous alla prima painting is a record of knowing when to stop, which is harder than it sounds and worth recognising when you see it. Fat over lean: the oil painting rule that stops a picture cracking This is the one technique that is not optional, and the one most worth a collector understanding. Fat over lean means each successive layer of paint must contain slightly more oil than the layer beneath it. Winsor & Newton , in their guide to the core oil painting rules, put it simply: the rule “is better understood if considered as ‘flexible over less flexible’,” and “each new layer of paint should contain slightly more medium than the one underneath, this making each layer more flexible and reduces the risk of the paint underneath cracking.” Fat over lean is just flexible over less flexible, and it is the difference between a painting that ages flat and one that cracks. The physics is unforgiving. Oil paint keeps moving for months as it cures, and a leaner layer dries faster and more rigidly than a fatter one. Stack a fast, rigid layer on top of a slow, flexible one and the top skins over and locks while the paint underneath is still shri