A web resource for artists with an interest in traditional and non-traditional materials and techniques.

Oil Paints

Technical Rules


Things you should know to help your paintings last for many years to come.

The archival properties of oil paints are one of the reasons they are still used to this day. Although acrylics show promise that they will last for many years they just haven't been around for that long so no one really knows if they will last 3 or 4 hundred years. To insure your oil paints are around as long as the one painted by the great masters you will need to know the rule about applying paint to your canvas.

Fat over Lean

One thing that every artist working with oils must know is the "fat over lean" rule. Oil does not dry by evaporation, but by oxidation or absorption of oxygen, forming a layer of linoxyn. When a layer of paint has dried it becomes less flexible or lean. Different colors tend to dry at different rates making it possible to apply a layer of paint over another layer and have the top layer dry faster. If this happens, the layer with more oil or "fat" will cause the "lean" layer to crack as the "fat" layer dries beneath it.

In my years of painting with oils I have noticed that the lighter colors tend to dry more slowly. (There are exception but in general light colors dry the slowest.) If I am in am trying to knock out a painting quickly I will use a fast drying medium or a drier in my white/light paints. If I dont over mix the drier with the paint it usually speeds up the drying time so its closer the amount of time the darker colors take to dry.

Advertisement