From: Darkroom User on

Is there any advantage or quality difference to using a pyro developer
instead of a normal developer such as D-76 or Xtol?
Developers like Pyrocat-HD, WD2D and PMK get mentioned a lot on the
internet photo sites.




--
Darkroom User
From: Richard Knoppow on

"Darkroom User" <Darkroom.User.69f9028(a)photobanter.com>
wrote in message
news:Darkroom.User.69f9028(a)photobanter.com...
>
> Is there any advantage or quality difference to using a
> pyro developer
> instead of a normal developer such as D-76 or Xtol?
> Developers like Pyrocat-HD, WD2D and PMK get mentioned a
> lot on the
> internet photo sites.
>
>
>
>
> --
> Darkroom User

Boy, have you opened a can of worms here:-) Pyro was
the first organic developer discovered and applied c.1860.
Previous developers were inorganic and nowhere near as
efficient. Pyro remained a favorite for the next fifty years
but was eventually supplanted by developers employing a
combination of Metol (AKA Kodak Elon and a bunch of other
names) and hydroquinone. These two in combination can make a
very wide varity of developers.
Pyro, in the right sort of formula produces a stain
image along with the silver one. The stain image is usually
a yellow or greenish brown. It increases the effective
printing density when the printing material is sensitive
only to blue light. Pyro became popular when it was
discovered that the stain image would act as a contrast mask
when films were printed on variable contrast paper, tending
to lower the contrast of the highlights. This was considered
desirable because some modern fils, tabular grain ones like
Kodak T-max for instance, can produce extremely high maximum
densities. Because the traditional Pyro developers tended to
be somewhat grainy some more modern ones were devised. PMK
in particular has become popular. However there may be
problems with it, for one thing the books on photographic
chemistry warn that borax is not compatible with Pyro and
should not be used in Pyro developers. PMK uses "Kodalk",
Kodak's trade name for sodium tetraborate, a borax compound.
I've seen several explanations of why this is OK in this
particular formula.
Traditional Pyro developers are mixed from two or three
stock solutions. This is because the most Pyro developers
are vulnerable to oxidation from the air and are not long
lived when mixed. When Pyro was the principle developing
agent a great deal of work was put into devising
_non-staining_ formulas. This is because the effect of the
stain on printing density is not easily predictable and it
was found in motion picture practice that obtaining
consistent results was difficult. When D-76 was introduced
in 1926 it very rapidly displaced all other developers for
motion picture negative processing. This was partly because
it produced fine grain negatives but also because it was
more consistent and controlable than previously used
developers.
Pyro has a couple of advantages especially for tray use:
while it is itself rapidly oxidized it does not produce
aerial fog, secondly, its a fairly good desensitizer so is
advantageous when developing by inspection.
The short life was addressed in some two part forumulas
which included Metol. In these developers the Metol is
present mainly to preserve the Pyro although it also
functions as a developing agent. Kodak D-7 is an example.
The three part developer, often called ABC developer,
evolved over the years to the point where the published
formulas were all the same. Kodak D-1 is a classical ABC
developer. These are still quite satisfactory but are
probably a bit grainy for 35mm film.
Some early formulas used acetone as an intermediate for
generating carbonate (actually hydroxide) in solution.
Because the acetone is volitile these developers tend to be
inconsistent and are the main reason that Pyro got the
reputation for being inconsistent. The later formulas using
sodium carbonate are much more satisfactory but one still
has the problem of determining actual printing density and
contrast due to the stain image.
BTW, the stain is composed of a humic acid pigment, not
a dye, and is probably more permanent than the silver image.
Pyro will also work as a warm tone print developer but the
color may not always be a desirable one.
I collected a bunch of Pyro formulas which someone
kindly posted to their web site. It appears as a PDF at:
<http://www.nonmonotonic.net/Photochemistry/Richard%20Knoppow/Pyro_Developers.pdf>
There are some good articles on Pyro developers on the
web:
http://unblinkingeye.com/Articles/PCat/pcat.html
http://www.jackspcs.com/pmk.htm

A Google search for Pyro Film Developers will find lots
more.


--
--
Richard Knoppow
Los Angeles, CA, USA
dickburk(a)ix.netcom.com


From: IanG on

Yes there can be advantages and an increase in quality how much depends
on the way you work and the developer you choose.

Pyrocat HD gives finer grain, better sharpness and more tonality than
D76, although originally designed for LF negatives it's also used for
35mm &120 negatives.

In addition the negatives are extremely easy to print from, with
excellent highlights and shadow detail.

It's also a better developer for making negatives for Alt processes.

Ian


Darkroom User;886070 Wrote:
> Is there any advantage or quality difference to using a pyro developer
> instead of a normal developer such as D-76 or Xtol?
> Developers like Pyrocat-HD, WD2D and PMK get mentioned a lot on the
> internet photo sites.




--
IanG
From: Jean-David Beyer on
IanG wrote (in part):
> Yes there can be advantages and an increase in quality how much depends
> on the way you work and the developer you choose.
>
> Pyrocat HD gives finer grain, better sharpness and more tonality than
> D76,

What does "more tonality" mean?

I cannot believe it means a greater dynamic range, because films, with
very few exceptions these days, have way more dynamic range than can be
printed onto photographic papers.

While I no longer use D-76, it is certainly a fine-enough grain
developer for 4x5 negatives at sizes up to 16x20, I would say. And it is
certainly well capable of getting a density of 2.0 or greater from the
films with which I am familiar.

Now it may well produce a slightly different curve shape, though that is
mostly determined by the design of the film. And some people obviously
like different curve shapes from others. I prefer short toe curve shape,
where most people seem to prefer a longer toe than I do. The only
disadvantage of short toe, in my opinion, is that if you underexpose, it
is just not there. So if you pop away on street corners in rapidly
changing conditions, Garry Winogrand style, you may prefer a longer toe
than I do. I believe he mostly used Tri-X in his Leicas.

> although originally designed for LF negatives it's also used for
> 35mm &120 negatives.
>


--
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From: craigclu on
I've settled on PyroCat-MC as my main developer, especially with
medium format and this combo is very nice with HP5+. I've been a
darkroom rat for 40+ years and always maintained some "go-to"
combinations when things needed to be predictable and absolutely give
usable results. I also played with many films and developers because
it kept my interest and imagination stirred up. As I've gotten older
and tinker less, I've appreciated the PyroCat variants because of 3
primary reasons:

1. Superb highlight control.... It virtually eliminates clipping and
allows me to have great shadow detail and not fear blown highlights.
Most films behave predictably at 1/2 box speed as a great starting
point and exhibit this basic behavior.

2. Great skin tones. People pictures just seem to print themselves
with a beautiful tone spread that gives a 3D effect and depth to
faces. Its sharpness and edge effects make eyelashes pop but somehow
is also kind to crows' feet, etc.

3. It solved most of my scanning headaches. The tonal range depicted
and smooth grain characteristics are especially compatible with
scanner's rendition with very little of that grain scatter appearance.
The edge effects aid in adding an apparent sharpness that translates
well in the digital process.

Over the years, I've had good success and a good understanding of most
of Ilford's films, Fuji and many of Kodak's. I started with D-76 and
still respect it as a great soup that one could happily use forever
and give up very little to anything else in general duties. FG-7 was
a favorite for many years and I also enjoyed DDX following that. XTOL
and the new TMY-2 seem made for each other, too. I only mention these
details so you don't think I'm a Pyro fanatic who's been to the
mountaintop!

The process is also easy and streamlined... I use a 1 minute initial
slow inversions cycle, followed by 1 gentle inversion per minute
(seems to add a bit of edge effect without getting exaggerated).
Follow with a double water rinse (no stop bath) and then fixing in
TF-4. Following washing and a drop or 2 of wetting agents, they also
seem to sheet off and dry spot free, too. Some films show some
emulsion expansion (sort of a frosty look with bright back light) and
some show an etching/raised effect on the emulsion side but they seem
to settle down after drying.

I wish someone would have promoted giving it a try earlier in my
darkroom escapades. I would encourage giving it a shot. A neutral or
alkaline fixer can aid in keeping the stain effect consistent with
Pyro (they're effective and pleasant to use anyway).

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