PMK Film Base Stain

Alan9940 · Mar 9, 2023

I haven't used PMK in many years and I've never used Fomapan 400 film, but I got the itch to play a little so I mixed up some stock PMK and shot a couple 4x5 tests. The film base (that is, edges) reveals more stain than I guess I'd expect. I didn't use an after-bath. I used a water stop, TF-4 fix, and washed for 20 mins. According to Hutching's book, the stain intensifies a bit during the wash. Just curious what other PMK users see vis-a-vis stain on the clear film.

Rick A · Mar 9, 2023

I've been using PMK for everything for many years, I really don't pay attention to the stain, I just enjoy the printing.

DREW WILEY · Mar 9, 2023

An alkaline after bath only adds to the overall fbf, and not to the meaningful differential stain itself. Gordon Hutchings allegedly recanted his original advice for an alkaline after-bath, and I stopped doing that myself. The image stain helps with highlight gradation control. And I prefer the yellow-green stain of PMK to the brownish one of Pyrocat. Foma 400 does fine in PMK, and gains a reasonable amount of beneficial stain.

Rick A · Mar 9, 2023

DREW WILEY said:
An alkaline after bath only adds to the overall fbf, and not to the meaningful differential stain itself. Gordon Hutchings allegedly recanted his original advice for an alkaline after-bath, and I stopped doing that myself. The image stain helps with highlight gradation control. And I prefer the yellow-green stain of PMK to the brownish one of Pyrocat. Foma 400 does fine in PMK, and gains a reasonable amount of beneficial stain.

I did read an article where Hutchings recanted the use of the after bath. My main film is Fomapan 100 in PMK, I can get nearly any effect I desire without having extra developers. PMK accentuates atmospheric conditions making fog and rain storms really pop.

Patrick Robert James · Mar 9, 2023

I pretty much echo what Drew said. After using PMK for years, then Pyrocat for years, I switched back to PMK after doing a deep dive and noticing that I got better highlights with it. I've found it to be more reliable too. I've seen so much jerking around with staining developers over the years but I think PMK is the best.

I only did the second after fix bath a few times way back when then stopped. Of course I could say I was a genius and knew that it didn't help before even Hutchings, but the truth is I am just lazy.

One thing to note about staining developers like Pyrocat and PMK is they don't like older films. The amount of base fog I got with Pyrocat at times compared to Rodinal was pretty dramatic.

DREW WILEY · Mar 9, 2023

I use PMK for nearly all my pictorial film development, with just a few exceptions. However I do keep other developers on hand for certain technical lab applications. I've tried a number of "pyro" options, including a couple of my own devising. But PMK has been pretty close to ideal for me right from when it was first formulated and published. I don't recommend it for rotary development.

Patrick Robert James · Mar 10, 2023

DREW WILEY said:
I use PMK for nearly all my pictorial film development, with just a few exceptions. However I do keep other developers on hand for certain technical lab applications. I've tried a number of "pyro" options, including a couple of my own devising. But PMK has been pretty close to ideal for me right from when it was first formulated and published. I don't recommend it for rotary development.

I use it for rotary development, but I use a lot. For example, in the JOBO 3010 I use a liter. Far more than is necessary. To use less, do what Bob Carnie does and split it into two, half the time for each. I'd rather just use more which keeps the oxidization at bay.

Alan9940 · Mar 10, 2023

Thank you all for the input.

I have used PMK in Expert Drums on my Jobo in the past and followed Bob Carnie's suggestion of splitting into two for half the time each. Never had any issues working this way.

DREW WILEY · Mar 10, 2023

Well, that requires a large volume of chemistry at a time, compared to other options. One those options was to displace the air in the tank with inert argon gas; another was to switch to a different tweak of pyro meant for rotary processing, like Rollo Pyro, or to
something more resistant to oxygenation like Pyrocat HD.

Rick A · Mar 10, 2023

DREW WILEY said:
Well, that requires a large volume of chemistry at a time, compared to other options. One those options was to displace the air in the tank with inert argon gas; another was to switch to a different tweak of pyro meant for rotary processing, like Rollo Pyro, or to
something more resistant to oxygenation like Pyrocat HD.

I do all my LF film rotary using PMK in Unicolor drums, only 250ml per run (4-4x5, 2-5x7, or 1-8x10 per run). I've never had any issues other than the day I accidentally did a two bath run with a pair of 5x7's. I forgot to mix part B before pouring the developer into the drum. Half way through the process (part A only) I realized my error and dumped the run and then ran an equal time with just part B to finish. The negatives came out good enough to make decent prints.

DREW WILEY · Mar 10, 2023

One of the issues with rotary dev is that lots of folks use Jobo units which run at too high an RPM even at the lowest speed setting, and that leads to excess oxidation.

When I briefly did rotary 8X10 sheet film processing with PMK a long time ago, even with my own better-controlled drive system, I got printable negatives all right, but with an awful lot of annoyingly excess fbf.

PMK Film Base Stain

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