I have found PMK and development of 4x5 films OK with 2509 drum and reels, if a prewet of about 5 minutes in water + wetting agent is done. I find no uneven development in doing so. I develop manually with a home-made roller base, and speed of 30 rpm. The only problem (however slight), is the oxydation of developer. Who ever tried a lower speed, say between 5 and 15 rpm ? I recognize this speed must be created manually or with an electric engine.(posted 9779 days ago)