GB/T 39307-2020 Fluorescent whitening agents, Determination of chromaticity and whitening intensity, Plastic chromadizing regulations prescribe technical methods for the determination of chromaticity and whitening intensity of fluorescent whitening agents using plastic chromadizing method. This standard is applicable to evaluating the effect of fluorescent whitening agents by preparing and testing Resin whitening swatches. During the test, visual comparison of chromaticity or determination of whitening intensity using a color measuring instrument is carried out by making the sample into a swatch under the same conditions as the standard sample. The standard also specifies the materials, instruments and equipment required for the experiment, as well as the test procedures, ensuring the accuracy and Repeatability of the measurement results.