To choose the adequate materials for apparatuses of the continuous manufacturing process, the reactivities of materials to the following solutions were tested. 1. Solutions of chemicals at 70°C, which would come in contact with apparatuses. 2. Ten % silver nitrate solution at 70°C. 3. A high speed photographic emulsion at 5°C. Then a photographic emulsion was prepared using the silver nitrate solution in which a piece of material chosen by the above mentioned test had been immersed. This emulsion was compared with the same kind of emulsion prepared by untreated silver nitrate solution. Moreover, the physical strength was tested by the following method: emulsion at 70°C was continuously pressed into the pipe made of the material. Then, among metals Cr-Ni-Mo-steel was chosen out, and among synthetic resins hard polyvinyl chloride containing no plasticizer was chosen out.