Abstract: A method for the quantification of the one or several of the physical properties selected from dry tensile strength, hydrophobicity, debonding energy, bursting strength, wettability and printability of pulp and/or paper which method comprises(I) developing a calibration model by(I.a) registering absorption, reflectance or emission spectra of reference samples of paper of known properties as defined above to develop learning sets;(I.b) processing the spectral raw data, to reduce noise and adjust for drift and diffuse light scatter;(I.c) performing a data analysis by applying chemometric techniques to the processed learning sets; and(II) determining the unknown properties as defined above of pulp and/or paper by registering the absorption, reflectance or emission spectrum, in correspondence to (I.a), from the pulp and/or paper having unknown properties; processing the thereby obtained spectral raw data as according to (I.b); and applying the developed calibration model to the processed data.

Abstract: A method is provided for quantifying the amounts of performance chemicals selected from the group consisting of wet strength agents, starches and retention agents, hydrophobic agents and debonding agents, reacted or retained with the cellulose fibers in fluff pulp or paper. The method comprises (I) developing a calibration model by (I.a) registering absorption, reflectance or emission spectral raw data of reference samples of paper or pulp containing known amounts of the performance chemicals to develop a learning set; (I.b) processing the spectral raw data from the registered spectra to reduce noise and adjust for drift and diffuse light scatter; (I.

Abstract: A method for the quantification of the wet strength of paper in pulp and/or paper, comprising(I) developing a calibration model by(I.a) registering absorption, reflectance or emission spectra of reference samples of known wet strength to develop learning sets;(I.b) processing the spectral raw data, to reduce noise and adjust for drift and diffuse light scatter;(I.c) performing a data analysis by applying chemometric techniques to the processed learning sets; and(II) determining the unknown paper wet strength by registering the absorption, reflectance or emission spectra, in correspondence to (I.a), from the pulp and/or paper of the unknown wet strength; processing the thereby obtained spectral raw data as according to (I.b); and applying the developed calibration model to the processed data.Optionally, a data analysis step as according to (I.c) can also be applied to the processed spectral raw data from the paper having unknown wet strength.