Question: is galkyd fat or lean?
Answer: In the initial layers, the oil medium (fat) is mixed with Gamsol (lean). As you add layers, increase the oil content of the medium by adding Galkyd oil painting mediums or a drying oil (Linseed, Stand or Poppy). The bottom layers will have more Gamsol and less oil. The top layers will have more oil and less Gamsol.