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ISO 8791-4 Porosity (Parker Print-Surf)




ISO 8791-4


Determination of roughness/smoothness (air leak methods) — Part 4: Print-surf method


ISO 8791-4 Porosity specifies a method for determining the roughness of paper and board using an apparatus which complies with the Print-surf method, as defined in this part of ISO 8791. It is applicable to all printing papers and boards with which it is possible to form a substantially airtight seal against the guard lands of the measuring head.


The test piece is placed between a circular flat metal sensing surface and a resilient backing, and inner and outer circular lands form a seal with the test piece. Under the influence of a pressure difference, air flows across the measuring land between the measuring land and the test piece. The rate of air flow is measured on a variable-area flowmeter, or the pressure difference across the measuring land is compared to the pressure difference across a known impedance. In both cases, the result is expressed as the air gap, in micrometres.


IPS tests using a soft backing and 980 kPa clamping pressure (offset) unless other test parameters are requested by the customer.


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SGS-IPS cannot sell or otherwise provide standards, specifications, or test procedures to third parties.