This standard defines a calculation method for the CIE 1976 Lab * (CIELAB) Color space, with the aim of providing a uniform Color space for color measurement and comparison. The CIELAB Color space improves visual uniformity in traditional Color spaces by converting tristimulus values (X, Y, Z) to Lab coordinates, making the perception of Color differences more accurate. The standard includes how to calculate Lab coordinates and their corresponding color difference values, and describes how to use these coordinates to evaluate the relative perceived size of a color difference. This standard applies to Color stimulation using CIE 1931 or CIE 1964 standard Colorimetric systems and is widely used for Color measurement of reflective and transmissive objects. The standard does not cover the more complex Color difference formula based on CIELAB or the CIELUV Color space.