A method for the determination of a cellulosic-fibre property, namely,
residual lignin content or Kappa number of chemical pulp, with the aid of
a spectroscopic technique obtained over a range covering the visible and
the near-infrared regions of the electromagnetic spectrum, comprising
exposing the wet fibres to a light source covering a range in the visible
region of 350 nm to 750 nm and a range in the near-infrared of 1100 nm to
2400 nm, reflecting light from the wet fibres, establishing a spectrum,
comparing the spectrum with a known spectrum of the property and
evaluating the comparison; the method has particular utility in a pulp
manufacture line; an apparatus is described for carrying out the method.