This method describes the use of the MIT-type apparatus for the determination of the folding endurance of paper. An exhaust fan arrangement maintains the folding head at room temperature.
The MIT tester is suitable for papers of any thickness; however, if the outer fibrous layers of paper thicker than about 0.25 mm (0.01 in.) rupture during the first few folds, the test loses its significance.
The procedure for the Schopper-type apparatus is given in TAPPI T 423 "Folding Endurance of Paper (Schopper-Type Tester)."