Photography & Stereophotography & even a bit of Holography

(Eventually I will get a stereo shot or two up here; haven’t had the time yet. In the meanwhile, I want to discuss the joy of Pyro.)

Pyrogallol, informally known far and wide as pyro, was the first really successful photographic developer. It was introduced in 1851. In his book The Negative, Ansel Adams says it may be the finest developer. He regrets (if I recall correctly) that it is not easily controlled.

I won’t ruin Gordon Hutchings’s story by telling it to you here; he does a better job than I would anyway. Suffice it to say that Hutchings has succeeded in controlling pyro, and has written a book about it with Ralph Talbert. No surprise, the title is The Book of Pyro, and if you can’t find it at your local library or professional photo shop, you can get it from The Photographers’ Formulary, 800 922 5255 (406 754 2891 if you’re in Montana). Their snailmail address is P. O. Box 950, Condon, MT 59826 (or at least, it was when they issued the catalog I’m looking at). They’re wonderful. I think the catalog costs a dollar...

I had been curious about pyro ever since I first heard about it, and when I finally got my hands on a copy of this book I just went nuts. Pyro, it turns out, though it is toxic (mix all solutions either outdoors or in a fume-hood, and wear rubber gloves whenever you handle the stuff in any form), really is about the most amazing developer there ever was. It also interacts well with certain other developers, which fact is at the heart of Hutchings’s work.

Pyro is a staining developer. Not only does it tan (harden) the gelatin of the emulsion around each silver grain it develops, it also stains (colors) that region. The color varies with the formulation of the devloper. Most of them produce a greenish or greenish yellow stain, but there are a few that are purple or brown. The stain image does not have the same kind of grain structure as the silver image. In fact, it doesn’t really have any particular “grain” structure at all. This does not mean that it has any better resolving power than the film would otherwise have; only that the transitions between developed and undeveloped areas are smooth. (If you’ve ever looked at a piece of developed film under a microscope, you know how jagged and clumpy it is.)

You can, in fact, bleach all the silver out of a good pyro negative and make prints from the stain image alone. Even if you don’t remove the silver, the stain contributes to the quality of the resulting prints.

I have ended up using a variant on Hutchings’s formula, in which I substitute a reduced amount of Phenidone™ for the Metol he prefers. That is not, I think, significant to anything you’re going to see on your screen — I doubt that anything so subtle could survive the process of scanning/digitization and compression that makes it possible to show things here at all — but it may have some slight effect on what I can capture on a negative. He reports that in high concentrations, Phenidone inhibits the staining that is so important to the way Pyro works; I get around that by using as little as I can reasonably get away with. I haven’t done any densitometry to find out whether my "PPK" formula stains as deeply as his "PMK", but I have successfully printed from a negative that I bleached the silver out of, so it can’t be interfering too badly.

Here’s a photo of my former stepdaughter, printed from a negative that I developed in Pyro. (Not bleached, though.)

Maggie Bergin


I have made some forays into holography. It is, of course, not possible with today’s technology to show you an adequate representation here. I would be happy to discuss holography with people; I am not by any means an expert, but I have sat down on the basement floor in Issaquah, Washington, and made holograms, even with other people present, which is a clear indication that I know at least something about it. It is, as those of you who have tried it can attest, a nontrivial matter to produce good holograms even in a lab on a stabilized table, much less on the floor of your bedroom!

One thing that helps a lot is a laser with good coherence length. My laser puts out less than a milliwatt, but it has coherence length vastly exceeding anything one is likely to encounter inside any ordinary building, so I can just put mirrors down & jam parts of the beam anywhere I want some light. I don’t have to worry about path lengths at all. Again, those who have done this, or tried, can tell you what a pain in the neck it is to have a laser with coherence length of, say, a foot or less. A thousand meters or so is a different world!

Note, added much later: one of the projects I was starting to think about when I was at the Joss Research Institute [which now seems to be defunct] involved pulsed holography. I was working on an old surplus ruby laser, and was thinking about maybe building a doubled Nd:YAG laser. (This could still happen, but probably not any time soon.) I have also thought about using dye lasers, particularly for color work, but it would be nontrivial to produce sufficient coherence length at any usable output energy.

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Last modified: Fri Jan 11 00:05:29 EST 2019