A Roller Developing Rack for Continuously Moving the Film during Processing by the Rack-and-Tank System--

In order to obtain machine type development in the rack process, a rack has been devised by means of which the film is moved continuously over rollers during processing. The film traces a helical path passing over rollers carried by an upper and a lower shaft, and is then led back along the bottom of the rack where a closed loop is completed by splicing the ends together. - The film is propelled by rotation of the upper shaft and rollers which, in turn, are driven by a motor and a reduction gear. The lower shaft is allowed a slight parallel displacement in the vertical direction to compensate for changes in the length of the film which occur when it is wetted. - A rewind and roll holder are mounted upon a removal plate for use in loading and unloading film or leader, and the film is removed to a reel for drying. A wide variety of processing conditions have been met successfully in processing sound and picture negatives and prints.