Oil

Oil paint is pigment in a drying oil, usually linseed. It stays workable for hours or days, which makes smooth blending and long sessions possible. It dries by oxidation, not evaporation.

Step by step

1. Tone the canvas with a thin, transparent wash (an imprimatura) so you are not judging values against stark white.
2. Fat over lean: each layer should be at least as flexible ('fatter', with as much or more oil) as the one below. Early layers can be thinned; later layers have more oil. This helps prevent cracking.
3. Alla prima (wet-into-wet) means finishing a painting in one session; indirect painting builds it up in layers such as underpainting, dead colouring and glazes.
4. Blend by laying neighbouring values next to each other and softening the edge with a clean, soft brush.
5. Varnish only when the painting is thoroughly dry — often six months or more for thick paint. Check your varnish maker's guidance.
6. Safety: ventilate well when using solvents, prefer low-odour solvent or solvent-free methods, and dispose of oily rags safely — rags soaked in drying oils can self-heat and catch fire. Lay them flat to dry or keep them in a sealed metal container with water.