Whiteness, brightness, colour and opacity testing
These surface optical properties are used in most specifications to define the visual quality of paper and board. The tests can be made on a range of materials including tissue, paper, copy paper, coated board, carton board and papers for most printing applications.
CIE whiteness, brightness, L*a*b* colour and opacity are all measured using a Technidyne Colourtouch PC spectrophotometer with a range of light sources.
Pira's UKAS, ISO 17025 accredited testing is performed to the following British standard and International standards: whiteness to BS ISO 11475; brightness to BS ISO 2470; colour to ISO 5631 and opacity to BS ISO 2471.
Testing of all of these properties is included in Pira's Paper Proficiency Service .