1 Scope
This document specifies a method for the calculation of light-scattering and light-absorption coefficients based upon diffuse reflectance measurements made under the conditions specified in
ISO 2469 using the colour matching function
y
¯
(
λ
)
and CIE illuminant C.
It is emphasized that the strict evaluation of the light-scattering and light-absorption coefficients requires conditions which cannot be achieved with the instrumentation specified here.
The values obtained by application of this document are dependent on the application
of the Kubelka-Munk equations, not to full reflectance data but to reflectance factor data obtained using the specified d/0° geometry and a gloss trap.
The use of the method is restricted to white and near-white uncoated papers with an
opacity less than about 95 %. Paper that has been treated with a fluorescent dyestuff
or that exhibits significant fluorescence can only be dealt with if a filter with
a cut-off wavelength of 420 nm is used to eliminate all the fluorescence effect in
the UVex(420) mode.
NOTE 1 The residual UV-level in the instrument may depend on whether the instrument is adjusted
to UV(C) or UV(D65) conditions prior to switc...