an aperture designed to permit variations in the amount of light reaching the recording material in relation to the magnitude of the received facsimile signals and the characteristics of the photosensitive recording medium Found on http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=721-14-48
an aperture designed to permit variations in the amount of light reaching the recording material in relation to the magnitude of the received facsimile signals and the characteristics of the photosensitive recording medium