View Full Version : Pyro Developer

Kent McClelland
10-May-1998, 19:17
I,m considering trying Gordon Hutchings' PMK pyro formula for negative developer . I would like to hear of any experiences--good or bad--that others may have ha d with this formula.

Thanks, Kent

Sergio Ortega
11-May-1998, 19:09
Kent, I've been using the PMK formula for some time, in all formats, and have h ad very positive results.

If you don't already have Hutchins' Book of Pyro, by all means get it. It's ver y comprehensive, well written, and will pretty much answer any questions you may have about PMK, not only about developing film in PMK, but about proper exposur e, printing, safe handling, etc.

Sooner or later, everyone brings up the extreme toxicity of pyro. Hutchins stat es that pyrogallol is the most toxic chemical one can use in the darkroom. Mixi ng the stock solutions from the dry powder, and possibly inhaling the dust, is p otentially quite dangerous. The new, pre-mixed liquid PMK solutions should solv e that potential problem. Also, handling of the stock solutions during developm ent, particularly with LF films in open trays, should always be done using rubbe r gloves, tongs, etc. Of course, common sense is the rule.

I find PMK superior to other developers in many ways. This is most evident in th e excellent separation in the higher values. PMK negatives reveal distinct and subtle nuances within these densities. Also, the staining characteristics of pyro yield negatives with less pronounced grain, even with fast films like TRI-x and HP-5. Print tonality also appears sm oother, more "liquid", when photographing certain types of atmospheric condition s. But then, these are very subjective qualities that one has to experience fir sthand.

Properly measuring negative densities can be a bit tricky at first. Initially, t he yellowish-green negative stain of the PMK pyro developer tended to throw off my densitometer readings. This colored stain acts as a filter, preventing accur ate density measurements. I've gotten pretty good at judging proper development and resulting densities by eye, particularly with sheet films.

I have not had good results with the Tmax films. I'm sure others have had posit ive results with these films, and can provide different opinions. My best resul ts have been with the Ilford films, particularly FP4+ and HP5, in 120, 4x5 and 8 x10, and Pan-F 50 in 35mm. Tri-X is good too, in all formats.

It is the most economical developer I've ever used. The stock solutions keep fo rever. Hutchins reports PMK does not work well with the rotary (roller-drum) de velopment processes, like the Jobo units. The reasons for this are rather techn ical, so I would direct you to his book. It does work very well with tray deve lopment and LF films, and also with 35mm and 120 in daylight tanks.

Give it a try, and draw your own conclusions. If you have any specific question s, please post a follow up or e-mail me directly.

Good luck , Sergio.

John Webb
12-May-1998, 20:13
I've been using Pyro as my developer of choice over the last the last six years with 35mm, 2 1/4, and with 4X5 and have been extremely pleased with the results. I normally shoot Ilford FP4, HP5 and sometimes Konica infrared.

Get PMK in solution from rather than the powdered form, and get a hold of Gordon s Hutchings book on PMK.