M. Graham Oils uses only the finest vehicle, Walnut Oil to make some of the finest oil paints on the market! Walnut oil provides a "unique refractive index" and will not yellow over time, which allows for incredible paint brilliance. Walnut oil's unique body allows for an increased amount of pigment suspension in comparison with other oils, giving their paint higher color saturation and tinting strength. Manufactured with only the finest example of each available pigment source, this paint contains no fillers, extenders, or adulterants, which have negative effects on color and how the eye perceives it.