This relatively young paint medium allows the artist painting in oils to approach oil painting differently by extending their freedom of expression and permitting a greater degree of spontaneity. Sennelier Oil Sticks have a similar composition to conventional professional quality oil colours except some neutral mineral wax is added to allow the colours to be formed into sticks. These colours are compatible with standard oil colours and have very high pigment concentration and excellent lightfastness. Sennelier Oil Sticks can be used on all traditional oil painting grounds: however, unlike Sennelier Oil Pastels, the Oil Sticks should not be used on unprimed paper. Oil sticks naturally form a thin dry skin over time after production which should be (easily) removed before use. Standard Oil Painting mediums, solvents and varnishes can be used in conjunction with Oil Sticks.