pyro

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Matt Ashbrook - 01 May 2004 06:50 GMT

I read somewhere about a guy that justified moving from large format to
medium format due to pyro.
What the heck is pyro and what does it do?
Is it dangerous/toxic? it sounds both!

Thanks,
Matt A.

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Jim Phelps - 01 May 2004 11:09 GMT

> I read somewhere about a guy that justified moving from large format to
> medium format due to pyro.
[quoted text clipped - 3 lines]
> Thanks,
> Matt A.

Matt,

Pyro, or Pyrogallol, or Pyrogallic Acid is one of the oldest developing
agents. It is a tanning developer and staining developer.

A tanning developer is one that 'tans' (like leather is tanned) the emulsion
and leaves it hardened and therefore less susceptible to damage.

A staining developer leave a proportional or general stain over the entire
negative.

The tanning part is easy to understand the benefits. The stain is hard to
understand. Pyro developers (as well as other staining developers) have
seen a resurgence of interest as this stain works so well with VC paper.
Pyro works (IMHO) better than the other staining developers.

Another benefit to the stain is it provides (in the case of Pyro) a stain
proportional to the silver. This stain also has a masking effect of the
grain structure and appears to the eye to have reduced grain (although grain
is not reduced). The developer also enhances edge effects and increase
apparent sharpness of the image. Pyro also increases the tonality of the
negative and decreases contrast (the mask provides this contrast reduction
by filtering blue light). All these benefits add up to an image that is
easier to print, especially on VC paper.

Pyro is a toxin. However, it's not as toxic as say Rat Poison or Drano.
Pyro gets a bad reputation as it is easily absorbed through the skin. For
those LF users who tray process, they may end up with Liver or Kidney damage
if they don't take rational precautions like gloves when the stick their
hand in the solution. Taking those rational precautions with Pyro (and all
chemicals) is prudent. Pyro is used in Hair Dye, Leather Tanning and some
cosmetics. So you may already be exposed to Pyro if you wear a leather belt
or shoes.

If I owned LF equipment, I would not take the step back to MF just because
of Pyro! You can never achieve the micro contrast or the tonality of a LF
negative with a MF negative. Same applies to MF and 35mm.

Pyro does not work with all films the same way and you will need to
experiment and maybe even give up old standby films to get better images.

Do I think the disadvantages outweigh the advantages? No! I'm not sure
Pyro is any more toxic than other chemicals I have in the Darkroom or even
under the kitchen sink. Heck, some paint thinners are more toxic if taken
internally. I just don't plan on drinking either of them;~)

Hope this had been helpful.

Jim

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Matt Ashbrook - 01 May 2004 13:37 GMT

Doesn't sound worth the trouble for my use. Idon't particularly like toned
prints, anyway.
This guy who back stepped to medium from large format did so (he says, not
me)partly because of the cost of equipment.
I just am getting started in large format and if I dump anything because of
cost, it will be the Hasselblad system! Now that's expensive! heck my 4 x 5
system is going to be into my wallet for the grand total of about $500 give
or take and that includes just having the bellows completely rebuilt.
No pyro for me, thanks.

Thanks,
Matt A.

> > I read somewhere about a guy that justified moving from large format to
> > medium format due to pyro.
[quoted text clipped - 53 lines]
>
> Jim

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Glenn Arden - 01 May 2004 14:20 GMT

Pyro does not tone the print. It tones the negative.

When you do not use a hardening fixer and stain the negative by reinserting
the negative in the developer you used in the developing the negative, it
turns the highlight areas a slight tan rather than grey. This tan color
when printed with a VC paper reduces the contrast between these higher Zones
to a lower Zone. This is a help when trying to reduce the range between
middle Zone VI and the highlights, which could be as be as high as Zone XII.

I do not know about sharpness, but it definitely will make high contrast
image easier to print.

| Doesn't sound worth the trouble for my use. Idon't particularly like toned
| prints, anyway.
[quoted text clipped - 71 lines]
| >
| > Jim

____________________________________________________________________________

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Jim Phelps - 01 May 2004 14:24 GMT

> Doesn't sound worth the trouble for my use. Idon't particularly like toned
> prints, anyway.
[quoted text clipped - 8 lines]
> Thanks,
> Matt A.

Matt,

Just to be sure you understand. It does not effect the color of the
print. It tones the negative.

You really shouldn't give up until you actually give it a try.

Jim

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Neil Purling - 04 May 2004 15:44 GMT

Anyone who can offer actual experience of this developer when used with
EFKE 25 and 50 ASA?

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Gregory W Blank - 04 May 2004 18:49 GMT

> Anyone who can offer actual experience of this developer when used with
> EFKE 25 and 50 ASA?

Yes.

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Neil Purling - 05 May 2004 06:58 GMT

Good.
I was interested in trying the developer as I have had problems with the
contrast of EFKE25ASA in certain lighting situations.
I am currently using some PL25 sheet film and the KB25 35mm.
I would like to know how easy it was to print the resulting negatives
compared to using a normal developer like Rodinal.
I have used this in the past but the contrast means scenes shot in sunlight
need a extremely soft filter to print.
I have amended my developement times and now rate the film at 25ASA in
daylight, not the 40 or 50 ASA in the literature ive seen.
It remains to be seen how my latest results print like as they were exposed
in bright sunlight too.
Any problems and I would like to try pyro and see if the highlights print
softer.

At least with 4x5 its easy to establish film speed as I make a test strip as
with a print when I progressively withdraw the dark slide and make multiple
exposures.
Obviously the kit I buy may be a different formulation and so I have to
establish a dev time for myself.

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Gregory W Blank - 05 May 2004 12:10 GMT

My testing indicates for my practice it is a true 25asa film.
With D23, PMK & HC110 that is for the PL25.
I wrote an article about the film for View camera
magazine on the film last year. If you wish I'll dig up the
issue number so you can research it further.

> Good.
> I was interested in trying the developer as I have had problems with the
[quoted text clipped - 17 lines]
> establish a dev time for myself.
>

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Neil Purling - 08 May 2004 18:12 GMT

I was going to try the Pyro kit made by Retro Photographic in the UK as they
also retail the Classic Pan and EFKE emulsions.
Which of these respond particularly well in pyro developer?
Are there any of the Ilford emulsions which work well?

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Gregory W Blank - 08 May 2004 19:48 GMT

> I was going to try the Pyro kit made by Retro Photographic in the UK as they
> also retail the Classic Pan and EFKE emulsions.
> Which of these respond particularly well in pyro developer?
> Are there any of the Ilford emulsions which work well?

Efke 25 in sheet film stains really well in my experience.
Delta 100 & Hp5 both take pyro stain very nicely likewise.

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Neil Purling - 09 May 2004 14:38 GMT

I have read some stuff that both Ansel Adams & Edward Weston both used
developers incorporating pyrogallol.
There are a few formulas for the stuff.
I was going to stick with ones I can buy mail order for now.
I beleive that you have to stain the film with the spent developer between
the stop bath & fixer.
Do you do that with all the formulas?
If the highlights turn an amber shade then it'd be like using a soft filter
grade so the highlights dont burn out.

In case the maker of the kit I get doesn't mention EFKE PL25 can you suggest
a start for experimentation. Like a time for Ilford Pan F, FP4 or the like +
or - whatever percentage.
Presently I have used Aculux and develope for Pan F time -30% for a speed of
25ASA.

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Jesse - 09 May 2004 15:40 GMT

From what I understood from reading The Book of Pyro and from the
instructions included in the PMK kit from Photographers Formulary you would
place the negatives in the spent developer AFTER the fixer and before the
final wash ..Hope this helps ..

> I have read some stuff that both Ansel Adams & Edward Weston both used
> developers incorporating pyrogallol.
[quoted text clipped - 11 lines]
> Presently I have used Aculux and develope for Pan F time -30% for a speed of
> 25ASA.

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Francis A. Miniter - 09 May 2004 16:36 GMT

>I have read some stuff that both Ansel Adams & Edward Weston both used
>developers incorporating pyrogallol.
>There are a few formulas for the stuff.
>I was going to stick with ones I can buy mail order for now.

Homebrewed or store bought, PMK is currently considered the best
formulation. I homebrew it.

>I beleive that you have to stain the film with the spent developer between
>the stop bath & fixer.

Wrong. If you are using an acid fixer, it is advisable to put the fixed
film into the spent developer again to intensify the stain. If you are
using an alkaline process (no stop bath and no hardener in the fixer),
the re-bathing is not needed.

>Do you do that with all the formulas?

As noted above, it has to do with the alkalinity or acidity of the
process used.

>If the highlights turn an amber shade then it'd be like using a soft filter
>grade so the highlights dont burn out.

I do not understand. Pyro is designed to be used with variable contrast
papers, and the use of standard filtration is expected. Pyro adds a
variable contrast component that no filter can achieve on its own.

>In case the maker of the kit I get doesn't mention EFKE PL25 can you suggest
>a start for experimentation. Like a time for Ilford Pan F, FP4 or the like +
[quoted text clipped - 3 lines]
>
>

I use PMK with FP4. I find development times of 12 to 14 minutes work
best. Anchell and Troop, The Film Developing Cookbook, give 7.5 minutes
for Pan F in PMK, but they also gave 10 minutes for FP4 and that was too
little. They do not give a time for EFKE PL 25 and I have no experience
with it.

Francis A. Miniter

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