Pyro...what's all the fuss please? : LUSENET : B&W Photo - Film & Processing : One Thread

Greetings all, I've seen a few comments here about Pyro or PMK film developer. Could someone tell me what all the fuss is about it? From what I recall, about the only famous classic photographer who used it was Weston. I currently shoot tri-x 400 in 6X7 format developing in HC-110 as per the technique Picker outlines in "The Zone VI Workshop". I was hoping to learn just what the Pyro 'mystique' is and what it might do that the HC-110 will not. Ansel Adams did not seem terribly thrilled with Pyro...he barely mentions it in his text on FILM. Curiously....Howard

-- Howard Posner (, March 15, 1998


I may be in the minority on this subject, however, I have used PMK with a number of different film types (APX-25,T-Max 100 &400, Ilford FP4) in 120, 4x5 and 8x10, and have been underwhelmed. IMHO, the additional precaution and processing work required far outweighs the benefit.

-- Harold Todman (, March 16, 1998.

The fuss about Pyro

All the 'fuss' is because PMK develoer produces negatives that print with unusual depth and luminosity. (Luminosity is that rare quality in a print that makes it seem to be lit from behind, a glow, if you will.) In addition, because PMK is a staining developer (part of the density is made up of stained gelatin instead of silver halide grains) there is very low graininess. PMK forms Mackie lines, giving extreme sharpness and acutance. PMK was formulated by Gordon Hutchings ten or so years ago and was not available to Edward Weston or Ansel Adams. PMK is no more dificult to use than any other developer once it has been mixed into stock solutions. You must use a water stop bath as acid will remove the stain. Likewise you must use a non-hardening fixer, like F-24. The best fixer (for any film) is Photographers Formulary TF-4 alkaline fixer. There is a little more time due to the 'redevelopment' of 2-3 minutes after fixing. Instructions are provided in the mix kit available form Photographers Formulary ( or 'Gordon's Book of Pyro' or Steve Anchell's 'Darkroom Cookbook.' If we strive to produce 'fine prints,' then going to a little more trouble to achieve them should not meet with so much resistance. Anyone can produce mediocre work without much trouble. I hope we are beyond that!

-- Michael D Fraser (, March 16, 1998.


Thanks for the reply...just how 'dangerous' is the PMK prep? And how true is the allegation that you must use VC paper to see the best results? Regards, Howard

-- Howard Posner (, March 16, 1998.

PMK: some simple cautions

PMK once it is mixed in solution is not much more dangerous than any other B&W chemistry; certainly less dangerous than formalin fixer used in color processing. Pyrogallol is a fine dusty powder and can be toxic if breathed or ingested. If you are mixing from dry chemistry, use a dust mask and latex gloves. Don't drink the solution or splash it in your eyes. Common sense. I've used PMK for several years and have no ill effects from it. If you accidentally get some into your system you will imediatly notice its distinctive taste and will be able to take appropriate action.

-- Michael D Fraser (mdfraser@earthlink.neet), March 16, 1998.

PMK toxicity

Thanks for the reply.

1-I will be using liquid concentrates not powder. 2-OK...let's say I get the 'distinctive taste'. Just what do you mean by taking 'appropriate action.'? I've no idea....


-- Howard Posner (, March 17, 1998.

"PMK toxicity"

Both the Book of Pyro and the intructions sheet packed with the developer kit give safety precautions and first aid intructions. Unless your are careless or sloppy, it is unlikely you will ever encounter problems. The warnings are posted just to be extra safe. Household cleaning agents are much more dangerous than PMK! For example combining chlorine bleach and amonia will produce extremely toxic fumes that will kill you quite quickly. Last time I looked there were no warnings on those products. Somehow people are more frightened of photo chemistry than cleaning agents. Go figure!

-- Michael D Fraser (, March 18, 1998.

Relative age of pyro developer formulas?

Michael wrote:

PMK was formulated by Gordon Hutchings ten or so years ago and was not available to Edward Weston or Ansel Adams.

I'm certainly no expert on photographic processes, but found the following in John S. Carroll's "Photographic Lab Handbook", fifth edition 1979, ISBN 0-8174-2486-5:

Trihydroxybenzene (pyragallol, pyrogallic acid, pyro, and so on) is an early developer, now all but obsolete. It produced a variety of results depending upon the alkalinity of the developer in which it was used; thus, it was a highly flexible developer, but its severe staining tendency caused it to lose popularity as more modern as more modern developing agents came into use.

So, I take it Hutchings' PMK formula is recent, but the use of pyro in developers is relatively ancient? It is mildly amusing to note the comment in Carroll's text that the stain is a liability.

Dana K6JQ Dana@Source.Net

-- Dana Myers K6JQ (Dana@Source.Net), March 21, 1998.

Re:Relative age of pyro developer formulas?

While pyro is one of, if not the earliest developer, it was not until Gordon Hutchings formulated PMK that it became practical for modern films. In early pyro formulas the stain was unpredictable and difficlult to control. Other pyro developers (Kodak D-1, Weston's version of ABC pyro, etc.) cause a loss of film speed. When pyro is combined with metol, the result is full film speed and excellent stain characteristics. See the December '97 issue of Camera Arts Magazine for an excellent article by Gordon Hutchings.

-- Michael D Fraser (, March 21, 1998.

The biggest change in PMK from the older pyro developers is the use of sodium metaborate as the accelerator. The older formulas used chemicals that were higher alkali agents and caused very unpredictable results and for the developer to lose its activity in only a matter of minutes, the PMK will have consistent activity for an hour after mixing. Pyro was the common developer of the last century and the early part of this century until the MQ and PQ developers came out. They were more stable and easier to use that is why they took over from pyro. Comparing developers today is really splitting hairs because they all use the same ingredients, Pyro developers and especially PMK are unique and do have a different look than anything else out today. I have used PMK for the last couple of years and love it for roll film although I have changed back to a conventional developer for most of my sheet film work, it is a little more predictable.

-- Jeff White (, March 21, 1998.

No one part of the photographic process can be looked at in isolation. Everything, from the lens to the print toner, makes up a system. (We might even include the light in a particular part of the world as part of that system also, such as the light at Point Lobos or Big Sur!) What film developer might work great in one person's system, might be lousy in another. I invite you to take a look at a photo of mine at: If this isn't "luminous" I don't know what is. What developer did I use? Pyro? Some exotic compensating developer I obtained from Photographer's Formulary? Surely not "soot & chalk" HC-110! Yes, HC-110. Film? Good old Tri-X 4164. Paper? Ordinary Ilford MC IV Fiber. Lens? An old 14" Kodak Commercial Ektar. So much for exotic materials. Thank Big Sur, Mother Nature, luck, a wonderful model and a decent photographer for the rest.

-- Peter Hughes (, September 21, 1998.

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