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ISO 2470-2:2008
Paper, board and pulps - Measurement of diffuse blue reflectance factor - Part 2: Outdoor daylight conditions (D65 brightness)
ISO 2470-2:2008 specifies a method for measuring the D65 brightness of pulps, papers and boards.
ISO 2470-2:2008 is limited in its scope to white and near-white pulps, papers and boards, particularly those exhibiting fluorescence which promotes the appearance of whiteness. The measurement can only be made in an instrument in which the ultraviolet energy level of the illumination has been adjusted to correspond to the CIE standard illuminant D65 using a fluorescent reference standard.
The source employed in ISO 2470-2:2008 excites almost twice as much fluorescence as the illuminant in ISO 2470-1. Consequently, ISO 2470-2:2008 is better suited for measuring the fluorescent contribution to the brightness. However, D65 brightness should not be confused with ISO brightness which closely approximates the brightness of papers viewed under indoor conditions.
International Organization for Standardization [iso]