Gurly-Hill SPS Tester - OpTest

This machine was developed for evaluation of printability of papers according to the US TAPPI standard. It readily measures three characteristics, that is, air permeability, smoothness, and flexibility. Its configuration is similar to the standard densometer. Particular attachments are used on the lower orifice plate. Under air pressure of the cylinder, air leaks across the paper layers and through the interstices of several specimens, or through the interval between special plug and specimen. The time necessary for allowing leakage of the specified volume of air is measured to evaluate the three characteristics.).