This International Standard specifies the procedure to be used for determining the whiteness of papers and boards, in order to obtain values which correspond to the visual appearance of white papers and boards, with or without fluorescent whitening agents, when they are viewed indoors. It is based on radiance factor data obtained over the full visible spectral range (VIS) in contrast to the measurement of ISO brightness, which is limited to the blue region of VIS.
In addition, it specifies a method for adjustment of the UV-content to correspond to the CIE illuminant C , since the results obtained when fluorescent whitening agents are present are dependent upon the UV-content of the radiation falling upon the sample. The CIE illumination C is taken to be representative of indoor illumination conditions because it contains a suitable proportion of UV-radiation . This method is not applicable to coloured papers containing fluorescent dyes. It is specific for the situation where the fluorescence occurs in the blue region of the visible spectral range.
This International Standard should be read in conjunction with ISO 2469.
NOTE 1 It is recognized that the CIE-whiteness equation was developed in the context of the CIE standard illuminant D65 [10], but the similarity between the relative spectral power curves for the C and D65 illuminants within the visible region and the closeness of their correlated colour temperatures (6 770 K and 6 500 K respectively) is taken as a justification for the use of the analogous whiteness equation with the CIE illuminant C.
NOTE 2 A related International Standard, ISO 11475 specifies the procedure for obtaining values corresponding to the appearance of papers viewed under the CIE illuminant D65.
ISO 11476:2000 history
2016ISO 11476:2016 Paper and board - Determination of CIE whiteness, C/2° (indoor illumination conditions)
2010ISO 11476:2010 Paper and board - Determination of CIE whiteness C/2° (indoor illumination conditions)
2000ISO 11476:2000 Paper and board - Determination of CIE whiteness, C/2° (indoor illumination conditions)