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emco IAS Calender Blackening tester

emco IAS Calender Blackening tester
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Price: 0 VND
Manufacturer: Emco - Germany


Calender blackening is the optical turbulent appearance of high-smoothed papers, which has a negative influence on the paper quality. The Calender blackening index measures the optical paper inhomogeneity in form of transparent parts in the paper which is caused by the calender.

Due to high local densities, especially at areas of increased basis weight as fiber crossing points, light-scattering interfaces in the paper sheet are reduced in calenders or supercalenders. One says, the fiber collapses. In incident light these transparent areas appear dark. The light is transmitted and partly reflected. This effect of "greying" of calendered paper caused the concept of blackening.

An objective assessment and quantification of the results of calendering can be achieved with the IAS module blackening. The system of Dr. Hermann Praast, Darmstadt, shows the best compliance with the subjective perception.


  • Measuring surface 10 mm x 10 mm

Calender Blackening quantities

  • Calender blackening index


  • Quality control in papermaking and paper converting industry


Brochure Calender Blackening tester





SC paper in incident light

4 mm x 5 mm


SC paper in incident light

0.25 mm x 0.28 mm






SC paper in transmitted light

4 mm x 5 mm


SC paper in transmitted light

0.25 mm x 0.28 mm


Technical data

Dimensions (HxBxT) 400 mm x 360 mm x 470 mm
Weight 12.5 kg
Measuring field 10 mm x 10 mm
Scope of supply Calibrated device with certificate, framegrabber, software, PC–ware




Catalogue and User Manual

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