The consistency of oil colors can be controlled with the use of oil painting mediums. The 2 fundamental oil paint qualities are called Short and Long paint.
With the controlled use of oil painting mediums the artist can produce a wide range of visual effects.
LONG OIL PAINT
Paint can me made long with a mixture of a little stand oil or painting medium. You will notice far fewer pointed peaks of paint after stippling with a palette knife. The peaks level off gently. Long paint leaves few brush marks and produces fluid brushwork.
SHORT OIL PAINT
The oil paint as it comes out of the tube is called short paint. It has a stiff, buttery quality which retains its brush marks easily; and when stippled with a palette knife creates many short, crisp peaks of paint, from which theterm is derived. Short paint produces a paint quality not easily obtained by any other means.