I am relatively new to 4x5 development....a "veteran" of the darkroom, however. I am using a Jobo CPE2Plus and the 2509 reels in the 2553 tank. I use Tmax RS mostly and periodically I have little purple or blue "undeveloped" edges on my film. The image is beautifully developed and the edge markings are nice and dark, but on the long edges of the sheets the emulsion hasn't completely cleared. What should I do to avoid this? Thanks experts!!