ISO brightness, R457 Brightness is calculated by summing a set of weighted spectral reflectance values which are obtained as a product of the spectral reflectance values and tabulated spectral values of the brightness function over a limited wavelength range from 400 to 510 nm. The effective wavelength of the brightness function is 457 nm 1.
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ISO brightness
After reading this article you will..
- know that the ISO brightness can be measured three different ways.
- know that the optical brightener will have an effect on the ISO brightness results.
- know that L* and Y C/2°values can be used for determining the lightness of the sample.
Content
Material testing and product properties
- Why test pulp and paper?
- Fibre properties
- Papermaking properties of pulp
- Fluff pulps
- Chemical analysis of pulps
- General physical properties of paper and board
- Optical properties of paper
- End-use properties of printing papers
- End-use properties of packaging papers and boards
- Tissue papers
- Permanent papers
- Reliability of results in physical testing of pulp and paper
- Quality control at the mill
- Standardisation in pulp and paper testing
Authors & references
Edited by:
Petteri Maijanen, ABB
Original author:
Juhani Vaarasalo
Based on: Vaarasalo J., Optical properties of paper (Chapter 8). In: Levlin, J-E. & Sjöderhelm, L. (ed), Pulp and paper testing (Book 17), Papermaking Science and Technology. Jyväskylä. 1999. Fapet Oy. pp. 163-181.
References:
- Pauler, N., Paper Optics, 2nd Edition, AB Lorentzen & Wettre, Kista, 2012, p. 54
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This page has been updated 31.03.2021
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