It is known to oscillate hollow processing drums to increase the agitation of the processing solution within the drum. However, these drums require a relatively large amount of processing solution to operate effectively, and are therefore unsuitable for unstable and/or single use processing chemistry. Described herein is a drum arrangement (10) in which a drum (14) oscillates within a generally U-shaped vessel (12), a processing tank (18) being defined between the drum (14) and the vessel (12). Photographic material (30) is driven through the tank (18) by a pair of drive rollers (24, 26) situated at the inlet (28) to the tank (18). The drum (14) is oscillated through an angle between 5° and 90° for effective processing.