Pyro Developers Question.
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From: Darkroom User on 4 Aug 2010 16:57 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 5 Aug 2010 14:07 "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 7 Aug 2010 08:30 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 7 Aug 2010 13:27 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. > -- .~. Jean-David Beyer Registered Linux User 85642. /V\ PGP-Key: 9A2FC99A Registered Machine 241939. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 13:05:01 up 13 days, 15:57, 4 users, load average: 4.42, 4.57, 4.56
From: craigclu on 7 Aug 2010 17:16
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). |