Nothing will prevent films curling during development, unless some mechanical means of keeping flat the film is adopted. A very good plan, however, with small films such as those of pocket kodaks is to roll the film, with the sensitised si le outwards, round a bottle, the film being held in place with circular rubber bands; the bottle is then revolved in a deep dish well filled with developing solution. Such treatment does not of course permit errors of exposure to be corrected during development. Special frames are made for printing from films, but ordinary frames can be used, the film being laid on glass.