Abstract: A photographic sheet material processing apparatus comprises a pair of processing rollers, means for feeding sheet material to be processed between the processing rollers. Processing liquid distribution means supply processing liquid to the rollers. The processing liquid distribution means comprise an open-topped distributor channel positioned adjacent the processing rollers, and means for feeding processing liquid to the distributor channel along the length thereof. The distributor channel is formed with a plurality of apertures through which processing liquid passes to the rollers. Overflow means associated with the distributor channel maintain a constant liquid head therein.

Abstract: Method and apparatus for DTR development of a lithographic printing plate of the type having a support possessing a natural deflection curvature under its ow weight and carrying an exposed silver halide emulsion layer in sandwiched relation an image receiving layer, wherein the plate is introduced into one end and removed from an opposite end of a DTR photographic developing bath for the emulsion layer. For such introduction, the plate is advanced through the nip of at least one pair of ingress feed rollers disposed one above the other above the bath surface along an ingress path that extends tangential to the nip at an angle of at least 5.degree. but less than 25.degree. to the horizontal and is unconstrained prior to its intersection with the bath surface. For its removal, the plate passes through a pair of egress feed rollers located above the bath surface along an egress path tangential to the egress roller nip at an angle of at least 5.degree. but not more than 25>to the horizontal.

Abstract: The area of moving rectangular sheet material, such as exposed photographic material needing photographic development, is calculated by advancing the sheet material at a known speed along a straight path with one axis, e.g. the length, of the material aligned with the path pass dual sensors. The first sensor determines the length of the sheet material, e.g. by measuring the time interval for the leading and trailing edges of the material to pass the sensor, from which in conjunction with the known speed of advance, the length can be calculated. The second sensor is elongated and extends angularly across the path of advance at a fixed bias angle .alpha. and measures the time interval for the leading and trailing corners (relative to the angular orientation of the second sensor) to pass the second sensor, from which the distance separating such corners along the path can be calculated.

Abstract: An apparatus for processing photographic sheet material comprises a housing, a first roller shaft supported within the housing and first and second processing rollers rotatable on respective roller shafts supported within the housing. The second processing roller lies substantially parallel to the first, and in line contact therewith. Biasing means bias the roller shafts towards each other. Means are provided for feeding photographic sheet material between the rollers. Each of the rollers has a radially outer zone formed of deformable material and has a radial dimension profile which varies along the length thereof. Such a roller construction enables the bleeding of images on aluminium lithographic printing plates processed by the apparatus to be reduced.

Abstract: Apparatus for processing rectangular sheets of photographic material in varying format sizes is equipped to calculate at least approximately the surface area of the sheets fed therethrough. For this purpose, the apparatus includes a sensor for determining a dimension, e.g. the length, of each sheet, a memory for storing the length and width dimensions of a plurality of sheet format sizes, and a control unit which compares the determined dimension of a sheet with the dimensions stored in the memory and upon finding a match therebetween gives an output signal indication of the surface area of the sheet. If more than one match is found, the unit gives an output signal corresponding to the largest format size having a dimension equal to the determined dimension.