Grumbacher Pre-Tested Oil Paint has long stood for professional quality oil color. Each color swatch has been tested for masstone and mixability, and has been painted by hand. It is further tested by our staff for characteristics such as lightfastness, drying properties, pigment dispersion and viscosity. Draw downs are compared and formulas are altered to ensure that our customers receive the best oil color at the best price. Truly a professional paint, the majority of our colors are single pigment with superior tinting strength and have a lightfast rating of 1-excellent. Made in USA. Since 1905, Grumbacher has been a brand trusted by students, professors, art conservationists, and professional artists throughout the United States.