BS ISO 9416:2017 pdf free

BS ISO 9416:2017 pdf free.Paper一Determination of light scattering and absorption coefficients
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 ifa 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 switching to the UVex(420) mode, but it is considered that this uncertainty in the residual level can be ignored in the application of this document.
Avoiding watermarks, dirt and obvious defects, cut rectangular test pieces approximately 75 mm x 150 mm. Assemble at least 10 of the test pieces in a pad with their top sides uppermost;
the number of test pieces should be such that doubling the number does not alter the reflectance factor. Protect the pad by placing an additional sheet on both the top and bottom of the pad; avoid contamination and unnecessary exposure to light or heat.
Mark the top test piece in one corner to identify the sample and its top side.
If the top side can be distinguished from the wire side, it shall be uppermost; if not, as may be the case for papers manufactured on twin-wire machines, ensure that the same side of the sheet is uppermost.
Remove the protecting sheets from the test-piece pad. Without touching the test area, use the procedure appropriate to the instrument and the working standard to measure the intrinsic luminance factor Ry,. of the top side of the test-piece pad. Read and record the value to the nearest 0,01 % of the
luminance factor.BS ISO 9416 pdf download.