CAN/CGSB-9.0 No./No.5-1993
Methods of Testing Pulp and Paper Brightness of Pulp, Paper and Paperboard

Standard No.

CAN/CGSB-9.0 No./No.5-1993

Release Date

1993

Published By

SCC

Latest

CAN/CGSB-9.0 No./No.5-1993

Replace By

85.060 85.040

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BOARD (PAPER), BRIGHTNESS (OF COLOUR), GEOMETRY, OPTICAL PROPERTIES OFMATERIALS, PAPER, PAPER PULP, REFLECTANCE FACTOR, SPECTROPHOTOMETRY, TESTEQUIPMENT, TEST SPECIMENS, TESTING, TESTING CONDITIONS, WAVELENGTHS

Scope

1.1 Absolute brightness is defined as the reflectance of blue light with a specified spectral distribution peaking at 457 nm compared to that of a perfectly reflecting, perfectly diffusing surface. Although no physical material has such a surface, the discrepancies between a reference material and the perfect diffuser can be rigorously determined. Reference materials thus calibrated establish the scale of absolute brightness. 1.2 Bleaching agents strongly influence the reflectance of pulp in this portion of the spectrum. Absolute brightness is thus used to monitor bleaching action. The method is not intended to be solely definitive in the case of materials having a pronounced color (Note 1) or containing optical brighteners. 1.3 Since the method utilizes an integrating sphere geometry, it may be used with materials having relatively rough surfaces. The specular component is excluded. The use of a relatively large sample aperture averages out point to point differences and minimizes the number of measurements necessary.

CAN/CGSB-9.0 No./No.5-1993 history

• 1993 CAN/CGSB-9.0 No./No.5-1993 Methods of Testing Pulp and Paper Brightness of Pulp, Paper and Paperboard