Abstract: In a process for measuring the equilibrium moisture in hygroscopic, laminar material coated on both sides, preferably in raw paper coated on both sides used as support for a photographic paper, by determining the relative moisture of the air in contact with the material, samples are removed from the material by a process which forms cut surfaces on the material and are introduced into a container which can be sealed off against the outer atmosphere, and after establishment of the equilibrium moisture in this container the relative moisture of the air contained therein is measured.

Abstract: A process for measuring the relative equilibrium moisture content, particularly of surface samples such as papers, films, woven material or the like, with which the sample is introduced into a hermetically sealable measuring tube and then the equilibrium moisture content arising from a temperature which is predetermined and adjustable by means of a thermostat is measured by a moisture sensor inserted into the measuring tube and not touching the sample. An apparatus serves to carry out the process which has a measuring tube which can be sealed on both sides and can be inserted into a thermostat, in which measuring tube frames are arranged for holding the sample to be examined, and which has a moisture sensor provided at the side sealing the measuring tube.