Commercial contact printers or process cameras usually use a pump-operated vacuum frame where the original and the photosensitive surface are pressed together against a flat glass by a grooved rubber mat connected to the vacuum source.
12.
Sometimes on a single transparent base, usually mylar, with Layer 1 being on the front and Layer 2 being on the back, in red and green, respectively, for later " separation " into component parts using a process camera.
13.
These studies led him to investigate the theoretical basis of the process camera and arrive at conclusions which standardises the hitherto empirical practices at process work . A camera and various pieces of half-tone equipment [ arrived ] from Britain [ & ] bybullock cart; soon after that, they moved out of 13 Cornwallis Street to a house not far away which Upendrakisore had made into a studio.
