Change search
ReferencesLink to record
Permanent link

Direct link
Fluorescence model for multi-layer papers using conventional spectrophotometers
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design. (DPC)
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design. (DPC)
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design. (FSCN)
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design. (FSCN)ORCID iD: 0000-0002-0529-1009
2012 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 27, no 2, 418-425 p.Article in journal (Refereed) Published
Abstract [en]

We present an extension of a Kubelka-Munk based fluorescence model in which we introduce an apparent scattering (SUV) and absorption (KUV) coefficient for all wavelengths below 400 nm. We describe a method for modelling the total radiance factor of multi-layer papers and for estimating the optical parameters (S, K and Q) of each layer. Assuming that the fluorescent whitening agent only absorbs below 400 nm, we are able to determine SUV, KUV and the apparent quantum efficiency, Q(UV,l) for 400 nm<l<700 nm, from spectral radiance measurements in the visual part of the electromagnetic spectrum. We test the proposed method on different layered constructions made of three individual pilot paper layers. The proposed method allows the papermaker to determine the illumination independent fluorescence characteristics of single- and multilayer paper layers using a conventional single-monochromator spectrophotometer operating in the visible part of the electromagnetic spectrum, and also to predict the radiance factor of fluorescing layered papers.

Place, publisher, year, edition, pages
2012. Vol. 27, no 2, 418-425 p.
Keyword [en]
Whiteness, Kubelka-Munk, Multi-layer, Fluorescence, Fluorescent whitening agents
National Category
Physical Sciences
URN: urn:nbn:se:miun:diva-16016DOI: 10.3183/NPPRJ-2012-27-02-p418-425ISI: 000315696000034ScopusID: 2-s2.0-84865261999OAI: diva2:511715
Available from: 2013-04-04 Created: 2012-03-23 Last updated: 2013-04-22Bibliographically approved
In thesis
1. Whiteness and Fluorescence in Layered Paper and Board: Perception and Optical Modelling
Open this publication in new window or tab >>Whiteness and Fluorescence in Layered Paper and Board: Perception and Optical Modelling
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is about modelling and predicting the perceived whiteness of plain paper from the paper composition, including fluorescent whitening agents. This involves psychophysical modelling of perceived whiteness from measurable light reflectance properties, and physical modelling of light scattering and fluorescence from the paper composition.

Existing models are first tested and improvements are suggested and evaluated. A colour appearance model including simultaneous contrast effects (CIECAM02-m2), earlier tested on coloured surfaces, is successfully applied to perceived whiteness. An extension of the Kubelka-Munk light scattering model including fluorescence for turbid media of finite thickness is successfully tested for the first time on real papers. It is extended to layered constructions with different layer optical properties and modified to enable parameter estimation with conventional d/0° spectrophotometers used in the paper industry. Lateral light scattering is studied to enable simulating the spatially resolved radiance factor from layered constructions, and angle-resolved radiance factor simulations are performed to study angular variation of whiteness.

It is shown that the linear CIE whiteness equation fails to predict the perceived whiteness of highly white papers with distinct bluish tint. This equation is applicable only in a defined region of the colour space, a condition that is shown to be not fulfilled by many commercial office papers, although they appear white to most observers. The proposed non-linear whiteness equations give to these papers a whiteness value that correlates with their perceived whiteness, while application of the CIE whiteness equation outside its region of validity overestimates perceived whiteness.

It is shown that the fluorescence efficiency of FWA is essentially dependent only on the ability of the FWA to absorb light in its absorption band. Increased FWA concentration leads accordingly to increased whiteness. However, since FWA absorbs light in the violet-blue region of the electromagnetic spectrum, the reflectance factor decreases in that region with increasing FWA amount. This violet-blue absorption tends to give a greener shade to the paper and explains most of the observed greening and whiteness saturation at larger FWA concentrations. A red-ward shift of the quantum efficiency is observed with increasing FWA concentration, but this is shown to have a negligible effect on the whiteness value. The results are directly applicable to industrial applications for better instrumental measurement of whiteness and thereby optimising the use of FWA with the goal to improve the perceived whiteness.

Place, publisher, year, edition, pages
Sundsvall: annat förlag, 2012. 158 p.
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 138
Whiteness, Perception, Colour Appearance Modelling, Paper Optics, Light Scattering, Fluorescence, Lateral Light Scattering, White-Top Mottle, Kubelka-Munk, Radiative Transfer
National Category
Paper, Pulp and Fiber Technology Atom and Molecular Physics and Optics
urn:nbn:se:miun:diva-17782 (URN)978-91-87103-50-6 (ISBN)
Public defence
2013-01-23, Sal 0111, Mittuniversitetet, Holmgatan 10, Sundsvall, 10:31 (English)
The Knowledge FoundationVinnova
Available from: 2012-12-20 Created: 2012-12-17 Last updated: 2012-12-20Bibliographically approved

Open Access in DiVA

Coppel_Fluorescence_model(966 kB)137 downloads
File information
File name FULLTEXT02.pdfFile size 966 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Gustafsson Coppel, LudovicAndersson, MattiasNeuman, MagnusEdström, Per
By organisation
Department of applied science and design
In the same journal
Nordic Pulp & Paper Research Journal
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 137 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 415 hits
ReferencesLink to record
Permanent link

Direct link