1.1 This method describes the spectral, photometric, and geometric characteristics of a light source, the illuminating and viewing conditions, and the procedures to be used for the visual evaluation of color differences of paper, including those containing fluorescent whitening agents.
1.2 This method specifies light sources which are selected to accomplish three objectives: (a) simulation of the actual and illuminating conditions of ultimate use, (b) employment of two light sources which are spectrally very different in order to exaggerate observable differences between sample and standard if any difference exists, and (c) employment of a UV radiator to detect the presence of fluorescent whitening agents (FWA) and assess their impact on final appearance.
1.3 This method is applicable when the testers have normal color vision.