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.

-- Philippe Bachelier (phbach@infonie.fr), December 20, 1997

Answers

PMK/JOBO

I have no experience with JOBO, but I can perhaps address your concerns on PMK oxidizing. Mix your developer just before you use it, say while your film is in pre-wet. Use distilled water because iron and other impurities will affect the solution. If your tank is sufficeintly full, oxidation should not be a concern. I develop sheet film by hand in trays and have not had a problem with oxidation.

-- Michael D Fraser (mdfraser@earthlink.net), December 22, 1997.

I do 4x5 in a Jobo 2509 with PMK, but hand roll at about 8-10 rpm. I use 400ml of developer which is a bit less than half full. The developer comes out very dark brown. It doesn't seem to be a problem, but I have heard the oxidation issue from several places. One remedy is to add about 30% more of solution A to compensate for the oxidation. I haven't tried this yet. I did try doubling the concentration of both solutions and keeping the development time constant. This increased negative contrast considerably (TMY), so a significant adjustment in time is needed. I haven't compared the quality of these negatives to the standard dilution. Anybody experimented with this?

-- Jim Snyder (axjes@uaa.alaska.edu), December 14, 1999.