An exhaustive search of these archives, as well as other sites referenced in PMK threads, provided no answers, so here goes. I'm going to be trying some 120 FP-4+, in a 2523 tank on a Jobo CPE-2+, with PMK obtained (liquid) from Photographers Formulary. A data sheet packed with the chemistry says to use at least 500 ml of working solution per 80 square inches of film. Hutchings, in his third (updated) printing, indicates at the bottom of page 58 that only 250 ml is necessary. I've never put more than 200 ml of anything in the 2523, but, if it can handle the greater volume without spilling developer out its center hole, and since PMK is very inexpensive, I wouldn't mind using 500 ml per roll. The processor's manual says its motor can rotate 600 ml, so there's no problem there. If anyone has data on process variablity with 250 ml of PMK per 120 roll, please share it here.

Finally, I've not located anything about use of a Jobo for this process, and need input concerning prewet. Some of you doing hand (inversion) processing are using a water bath prior to inducing developer, but how about in a newer small Jobo? Jobo's Web site offers nothing in this regard; its only comments relate to not using a prewet with Xtol.

Thanks in advance for your help.

-- Sal Santamaura (bc_hill@qwestinternet.net), January 16, 2001

Answers

Sal, look here: http://www.jobo-usa.com/jq/jq9502.htm

-- Don Sparks (Harleyman7@aol.com), January 17, 2001.

Thanks, Don, I'd already seen that. It covers processing sheets in Expert Drums, where a different set of conditions exist. Hutchings reports no oxidation or streaking problems with 2500 series tanks, thus no need to split into two runs or use nitrogen, etc. Neither this Farmer piece nor anything else I could find addresses the questions of capacity or roll film prewet.

-- Sal Santamaura (bc_hill@qwestinternet.net), January 17, 2001.

Greetings,

I don't have any hands on experience in this regard, but 'am about to give some rolo PYRO a try. From what I've read, PYRO oxidizes quickly and isn't recommended for use in a rotary processor, however Rolo PYRO was formulated specifically for rotary processing. I purchase it from Photographers Formulary (as a powder) and plan on using it in a JOBO processor. If the directions for the developer you have recommend using a minimum of 500 ml, then that's what you should use - at least until you have a baseline. Good luck!

Regards,

Regards,

-- Pete Caluori (pcaluori@hotmail.com), January 17, 2001.

You may want to verify this, but I believe FP4 has a wetting agent built in to it that promote even development. Pre-soaking film removes this, resulting in less even development. Although I've never used Jobo processors, I've had good results processing FP4 in PMK in Patterson tanks without a pre-soak.

-- Steve Wiley (wiley@mail.accesshub.net), January 25, 2001.