Holbein Artists' Oil Color is made with the purest of available pigments and is manufactured to the highest standard of quality control in the industry. The formulation and grinding/blending techniques for each color are modified to compensate for the inherent differences in the working characteristics of pigments. The result is an even consistency across the entire palette of 175 colors. Ground from 3 to 5 times as necessary to achieve a universally consistent viscosity, each stage in the manufacturing process is monitored for optimum quality. Throughout the production process, Holbein ensures its quality standards by test inspection of pigment purity, color tone, applicability and adhesion, physical stability, light stability, thermo-stability and anti-bacterial stability. The result is a world-class professional oil color without equal.