This document specifies the method for optical assessment of the contact angle between water and the surface of paper and board, where the process of droplet formation, application to planar substrates, or measurement of the droplet shape in contact with the solid is performed by automated equipment.

The limits of measurement are determined by the capabilities of the instrumentation used. The instrumental capabilities defined by this document use a digital image capturing system operating at a minimum of 50 frames per second and needs the ability to perform the first measurement after no more than 20 ms to 40 ms contact between the droplet and substrate.

The test method is applicable to most kinds of paper or board however it cannot be applicable to structured materials.