ISO 11475:2017 specifies the procedure to be used for determining the whiteness of papers and boards. The values obtained correspond to the visual appearance of white papers and boards with or without fluorescent whitening agents when they are viewed under the CIE D65 daylight standard illuminant. It is based on reflectance 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 D65 daylight illuminant[10][11], insofar as results obtained when fluorescent whitening agents are present are dependent upon the UV content of the radiation falling upon the sample. It is specific for white fluorescent paper samples where the emission due to the fluorescent whitening agent (FWA) occurs in the blue region of the visible spectrum.
This method is not applicable to coloured papers containing fluorescent dyes.
ISO 11475:2017 should be read in conjunction with ISO 2469.
NOTE 1 This document is based on the CIE whiteness formula, published in CIE 15.3-2004[9].
NOTE 2 A related International Standard, ISO 11476, specifying the procedure for obtaining values corresponding to the appearance of these products under indoor illumination, has also been published.