This International Standard describes the general procedure for measuring the diffuse radiance factor of
all types of pulp, paper and board. More particularly, it specifies in detail in Annex A the characteristics
of the equipment to be used for such measurements, and in Annex B the procedures to be used for
calibrating that equipment.
This International Standard may be used to measure the diffuse radiance factors and related properties
of materials containing fluorescent whitening agents, provided that the UV-content of the instrument
illumination has been adjusted to give the same level of fluorescence as a fluorescent reference standard
for a selected CIE illuminant, in accordance with the specific International Standard describing the
measurement of the property in question.
This International Standard describes in Annex C the preparation of fluorescent reference standards,
although the procedures for using these standards are not included, since their use is described in
detail in the specific International Standards describing the measurement of the properties of materials
containing fluorescent whitening agents.