DIN 53145-1:2012-03

This document - as far as it concerns methods and measurement instruments - is in line with International Standard ISO 2469:2007 "Paper, board and pulps - Measurement of diffuse radiance factor". The document differs from ISO 2469 in particular in the following: In accordance with ISO 2469, reference standards with known spectral reflectance factors have been provided by authorized laboratories. They are carried out in accordance with ISO by CEPI (Confederation of European Paper Industries) for the EU countries. According to 5.3, all calibrated primary white standards can be used. These can be manufactured from, for instance, opal, ceramics, PTFE or barium sulfate. The absolute reflectance factors shall be traceable to a national metrological laboratory. Contrary to ISO 2469, Working Committee NA 074-02-02 AA has realized the need to specify basic parameters for the evaluation of fluorescent, specially whitened papers as they are of significant commercial relevance and the measurement results on such papers depend more on the basic parameters than the non-fluorescent papers. The basic parameters for such papers are therefore described in DIN 53145-2. In many cases, denotation of the optical properties of papers is done using the standard colour values X, Y, Z. This fact has been taken into account in this standard by incorporation of tristimulus filters for measurement of RX, RY and RZ reflectance factors. Conversion of the measured reflectance factors into the standard colour values X, Y, Z depends on the used standard illuminants; it also depends on which standard colorimetric observer should form the basis.