This standard specifies a unified method for determining the blackness of various pigment carbon blacks using a reflectometer, with Standard Reference Black 3 (SRB3) as the benchmark. This blackness index is used to quantify the black color intensity of carbon black as a pigment, which is crucial for color quality control in products such as inks, coatings, and plastics. The core of the determination process involves using a dedicated reflectometer (also known as a blackness meter or colorimeter). Such instruments typically feature specific optical configurations (e.g., a 45°/0° measurement angle) and light sources, allowing for precise calculation of the blackness value by measuring the reflectivity of the sample relative to the reference carbon black.