The ASTM E 2175-01 (2021) Standard Practice for Specifying Polygonal Specphotometer Geometry provides specifications for the geometry and configuration of polygonal spectrophotometers. The standard specifies how the geometry of the instrument should be determined when using a multiangle spectrophotometer for Color measurement, including important parameters such as Measurement angle, Light source position, receiver angle, etc. By defining and standardizing the geometry of the photometer, the measurement result conformity between different devices can be ensured, thus improving the accuracy and repeatability of Color evaluation. The standard is widely used in Color Management, quality control and product development in the industrial field, especially in the color detection of Coating, Spinning & weaving products and plastics, and plays a role in standardizing the use of instruments and improving Measurement accuracy.