The MOD54 Large Format Film Processor is a 4 x 5″ sheet film holder for use in conjunction with a Paterson Super System 4 PTP116 three-reel developing tank. This holder accepts up to six sheets of a 4 x 5″ large format sheet film and permits standard inversion-type agitation methods during development.

The holder is designed with a notch system, similar to 4 x 5″ film itself, to facilitate easier loading and to ensure the emulsion side of the film is facing inward for greater protection against scratching.