color measurement in the material

Inline color measurement in the liquid paper stock

In paper production, the paper pulp is the first place where information about which can be color collected. Although the measurement results do not correspond to the results for the finished paper, a colour shift in the pulp is already an indication that the one color in the wet paper will differ. In this measuring phase, the optical optical brightener control can also be controlled.


The one color measurement in the fabric is used for:

  • Early detection of disorders
  • Control of dye addition
  • Mixture of 2 types of raw materials (e.g. dark and light) at a constant level
  • Monitoring the addition of recovered paper without significantly changing that color of the entire pulp
  • Testing the homogeneity of the paper pulp after dye addition

The ERX40 system for whiteness measurement is mounted in a stainless steel housing:

  • It measures directly in the thick matter (concentration: 3 % to 5 %) through a bypass system.
  • EG 50 R: The thin substance (approx. 1 % concentration) flows through a bypass to the measuring instrument. The measuring instrument then measures that color of water and fibres, and calculates what it will be like color in wet paper. Small changes in concentration have no effect on the measurement.
  • The ER40WF is a "lite" system that can only measure white levels.


The ES15Win and ES18Win software controls the measuring instrument and displays the data. These measurements can be connected to a control system. Colored bars indicate the deviation of the produced paper from the target value. The machine operator can see at a glance whether his paper is too light or too dark, too red or too green, too yellow or too blue, as well as the whiteness with and without UV excitation (ERX50P only).

Trend measurement

The installation of the system normally takes one day. A connection to the control system is also possible.

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