Pre-Tested is Grumbacher's flagship oil paint line. It's the product that, more than any other, represents the way they do business: with care, precision, attention to detail and taking nothing for granted. On a more specific level, it means simply the finest pigments the world can offer, milled in select alkali-refined linseed oil for the professional artist. Pre-Tested stands for optimal color development, high chroma, superior tinting strength, excellent adhesion, outstanding working properties and archival quality. Made in the USA.