About Pyro development

FROM: Tim Daneliuk 
SUBJECT: Pyro: A Report From The Trenches (Long)
DATE: Wed, 26 Feb 1997 22:11:48 -0100

I posted this to the pure-silver mailing list tonight, but thought
others might be ineterested as well...

PYRO: A Report From The Trenches (Tanks, really)


I have wanted to try pyro developer for film development for some time
now.  I was reluctant to do so, however, having read the numerous
horror stories of its dangers and how hard it was to control.  This
little epistle is a look at what I've discovered in the past few
months on this subject.

Why Bother?

First, why bother?  Why not used time-proven developers like HC-110
(which I love, but has nasty effects on grain when you push to N+1 or
more) or more recent brews like T-Max RS (which I hate because it is
not a one-shot developer unless you're J.P. Getty)?  The claim is made
that pyro-developed negs exhibit three important qualities:

1) Better edge sharpness
2) Ability to push process (N+...) while maintaining sharpness *without*
   significant grain degredation.
3) Easier to print negatives.

All three appear to be true, at least in some degree, in my experience
over the past several months.  My Tri-X negs from pyro development
have smaller grain and hold shadow detail noticeably better than the
same film in HC-110.  Also, highlights don't block as quickly - you
can burn down dense portions of a negative and usually find something
there other than dull gray.

I don't want to oversell this.  The differences are subtle but they
*are* noticeable.  If you have crappy technique, pyro probably won't
help, but if you're pushing the envelope of what you can squeeze out
of a negative, you ought to give this a try.

Why Is It So Hard?

Now, the issues.  Most of the literature on pyro warns you that it is
very active and therefore difficult to control. In particular, people
have found that you have to have very controlled agitation or
streaking of the negs will result. There is a lot of loose mumbling
about laminar flow patterns along the edges of the film and vague
references to the physics of turbulent flow (a non-linear mathematical
universe not for the faint of heart!).  Most serious pyro-maniacs (8-)
have thus resorted to either film tubes or the Jobo rotary processor.

Secondly, the active ingredient in pyro is very toxic and nasty stuff,
especially so if it is inhaled in powered form - no, I didn't inhale.
Fortunately, there is an excellent liquid form available from the
Formulary, called PMK Pyro, which is easy to mix.  Once mixed, you
still don't want it on your skin, but that's what rubber gloves are
for.  I should mention that it is rumored that Ansel had his bare
hands in it for years and lived into his 80s (that latter part isn't
rumor 8-). I still religiously avoid getting the stuff on me: I've
taken George Burns' thought to heart, who said, "If I'd known I was
going to live this long, I'd have taken better care of myself."

Pyro On The Cheap

I am basically cheap when it comes to buying darkroom gear.  Almost
all the equipment of significance in my darkroom was purchased used.
My enlarger is older than I am!  I'd rather spend the money on lenses
or going places to make new images (or beer, or...).  In other words,
I ain't plunking down $1500 for a plastic tube and motor assembly that
agitates my film during development.  Morever, I hate pouring stuff in
and out of tubes while processing.  I think it's because I actually
like sitting in the dark processing film, but that's another story for
my shrink.

The one concession to modern darkroom gear is a Zone VI Compensating
Development Timer.  This is timer which adjusts its speed based on the
temperature of the developer (it comes with a thermocouple probe which
you stick in the developer).  So "5 minutes" indicated may be more or
less real time depending on the actual temperature of the solution.
This timer has settings for both film and paper.  The idea is to
always develop paper, for instance, for "2 minutes" on the timer and
have it compensate for temperature variations by adjusting its running

When I first bought the timer, I was still processing 120 roll film in
stainless tanks.  I wanted to use the timer to help control this
process.  However, the temperature probe is kinda big and klunky and
there was no way it would fit in your typical stainless steel rollfilm
tank.  That, and the fact that I got a batch of new tank covers that
leaked light (#@$%^$%^) forced me to find a better way.

I wanted to go to open tank processing because an open tank would have
room for the temperature probe in it.  Roll film was easy - just drop
the loaded reels in an open tank of developer and away you go.  But
what about 4x5 sheets?  I really didn't want to resort to tray
processing.  I also didn't want the expense and complexity of a
nitrogen-burst agitation system.

It turns out the answer was already in my darkroom.  My Gravity Works
film washer has a removeable basket for sheet film.  This basket is
made to hold up to 20 sheets or so of film vertically and separated by
about 1/2" so that water can flow around the film to wash it.  All I
had to do was find a plastic tank which was large enough to hold the
basket and leave room for the temperature probe.  The darkroom gods
smiled and I discoverd that Tupperware makes a 1 gallon container that
is *perfectly* sized to do this.

Now to process film, I lay out 4 tanks - water pre-wet, developer,
stop, hypo.  I clip the thermocouple to the developer tank.  I load
the basket in darkness and lift it from tank to tank as needed.
Simple, cheap, and works like a charm.  Not a single streak on the
film, no fumbling with individual film sheets.

Pyro is a staining developer (the negs come out with an green/orange
tinge).  Part of the final negative density comes from the stain so
negatives will look underdeveloped when you look at your first one.
The stain is partly created when you develop the neg.  After you are
finished fixing the negs they go *back into the developer* immediately
for another 2 minutes to enhace the stain.  For this reason, you
should avoid hardening fixers which inhibit further stain formation.

Future Explorations

The Formulary sells their own odor-free fixer called TF-4 which has
the interesting property of being alkaline.  It is an alkaline PH
which causes pyro to stain.  I just got some of this stuff, but have
not yet tried it.  The claim is that you can fix in TF-4 very rapidly,
get complete staining, and not have to dump the negs back into the
developer when done.

The only down side is that you cannot use an acidic stop bath (which
means you must use water) and that you must *throughly* wash the
developer off before placing the negs into the TF-4 or you will get
unpleasant streaking.  In essence, this means that you have to have
moving water for a stop bath.  I'm going to use a Kodak Tray Syphon on
the stop bath tank in my setup to try this out.

If this doesn't have major payback, I'll go back to acedic acid stop
and a final 2 minutes in the developer as described above.

I also want to give T-Max a serious whirl. I've never gotten
tonal results from T-Max that I liked as much as Tri-X, but I love
the grain of TMX.  My first few rolls of TMX in pyro looked really

Other Thoughts
1) You do have to work in the dark with open tank processing 8-)

2) Somebody (Sexton?) has commented that the pre-programmed time-temp
   curves in the Zone VI timer don't apply well to modern films like
   T-Max.  I have noticed no problems, but my darkroom and the supply
   of distilled water I keep there are almost always between 68 and
   70 degrees F, so I may not be using the parts of the time-temp
   curve which is in error.

3) You are sticking your hands in pyro so USE GLOVES AND EYE PROTECTION
   during processing and cleanup.

4) You must agitate consistently and often - I lift the basket/reels
   every 15 seconds, 5 times. (Hutchings specifies a twisting
   agitation for reels which I more-or-less follow.)  You have to be
   careful when lifting and dropping the sheet film basket.  The film
   is held very loosely and moving the basket too rapidly can
   pop the film out of the edge guides which hold it in place.

5) If you're interested, Gordon Hutchings book on pyro is a must.

6) Because a significant part of the negative density comes from
   the stain, a normal B&W densitometer will not properly read
   the negs - this is all I have, unfortunately 8-((  I've used
   Hutchings recommendations as a starting point and have hand-tuned
   from there.  His starting points are very close if you use decent
   lab technique and have accurate thermometer and timer.

7) Gravity Works has changed the design of their baskets slightly which
   raises the sheet film up about 1/2".  This will not work in the
   1 gallon Tupperware tank mentioned above because the fluid will not
   completely cover the negatives when the basket is dropped in the
   I need to find a new tank for the newer basket type.

8) It's *really cool*, give it a try...
                         "Tundra" Tim Daneliuk
                      System Architect, Nets Inc.
                       email: tundra@netsinc.com
                          Voice: 847.827.1706
                          Pager: 630.223.0266

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