This standard specifies a standardized method for determining the color attributes (dominant wavelength and excitation purity) of paper and paperboard. Its core principle involves using the diffuse reflection method to eliminate interference from sample surface gloss on color measurement, conducted under D65 standard illuminant and a 10° observer angle to ensure consistency and comparability of measurements. The method is primarily applicable to paper products without added fluorescent materials but can also be extended to products containing fluorescent whitening agents after calibrating the ultraviolet radiation of the instrument's light source. The detection process typically requires the use of a spectrophotometer or a precise colorimeter to achieve accurate color measurement and analysis.