Abstract: An electrolytic cell comprises a housing (12), means (21) defining a liquid level (25) in said housing (12), a first contact surface (32) positioned above said liquid level (25) for making contact with a removable electrode (20) when positioned in said housing (12). A second contact surface (36) is positioned above said liquid level (25) and electrically isolated from said first contact surface (32) for making contact with said removable electrode (20) when positioned in said housing (12). A method of electrolysis in such a cell comprises supplying electrical power to said electrode (20) at an electrolysing potential (U.sub.P) and controlling the electrolysing potential (U.sub.P) in response to the potential (U.sub.2) sensed at the second contact surface (36). Control of the electrolysis process is possible without influence of any unknown and variable resistance between the first contact surface and the electrode.

Abstract: A processing apparatus comprises at least one wet processing station followed by a dryer in which wet sheet material comes into contact with heated drying air. Sheet material is fed over a static support member which supports the sheet material during drying. A drying unit is positioned opposite to and extending across the support member in a transverse direction, thereby to define a drying space between the support member and the drying unit. Drying air is fed to the drying unit to pass out through a drying air exit into the drying space. The support member includes a plurality of openings to allow drying air to pass therethrough, to ensure that the air flow is substantially the same whether a sheet of photographic material is positioned on the support member or not, while minimising the generation of turbulence.