An apparatus for the wet processing of photographic sheet material comprises at least one treatment vessel (12, 12', 12") having upper and lower openings (17, 18), one of the openings constituting a sheet material inlet and the other of the openings constituting a sheet material outlet, the inlet and outlet defining there-between a substantially vertical sheet material path (20) through the vessel. The vessel comprises a pair of rotatable rollers (28, 30) biased towards each other to define a nip (36) there-between through which the sheet material path extends. The apparatus is characterised in that the end faces of one roller lie in substantially the same plane as the end faces of the other roller and each roller is in sealing contact with a stationary sealing means (38) having a continuous contact line (52) which extends along the length of each roller (28, 30) and over the end faces of each roller, at least on the fluid side of said nip (36).