The fiber morphological analysis of samples is carried out by using a Valmet "Field-Flow-Fractionator" according to the principle of field-flow-fractionation. In this process, suspensions of the samples to be examined are prepared and measured with a stock consistency of 0.3 wt%. In the flow field of the fractionation coil, the physical separation of the fiber suspension into its individual fractions and their subsequent camera- and computer-aided analysis and evaluation takes place.

The following morphological parameters can be determined, for example: average fiber length according to TAPPI and ISO L(n) c, L(l) c, L(w) c, fines, fiber diameter, optical coarseness, curl, fibrillation as well as fiber length fractions.

With the help of this measurement, it becomes possible to follow suspension properties of fibrous materials in different processes and to draw conclusions about their behavior in the final paper product.