An arrangement for introducing a band light-sensitive material in daylight from cassettes into a developing device has a receiving part located on a developing device and light-tightly receiving a guide part of cassettes, at least one separating element subdividing the interior of the receiving part into at least two compartments so that a wide cassette can be received into the receiving part in the absence of the separating element or one or two narrow cassettes can be received into one or two compartments of the subdivided receiving part, and a closing element provided in each of the compartments and independently acting for light-tightly closing the respective one of the compartments.