Frisket

And while the Tympan is coming, he slips his Left Hand Fingers from under the Frisket to the hither outer corner of it, as well to keep the Sheet close to the Tympan in its position, as to avoid the jobbing of the lower side of the Frisket against the small square shoulder

As the pressman returns the inkballs to the inkstone, the journeyman closes the frisket and tympan.