Lippmann Photography and pinhole cameras

This is a forum exploring Lippmann photography.
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Ejs12006

Lippmann Photography and pinhole cameras

Post by Ejs12006 »

I am trying to make Lippmann photographs using PFG-03M holographic film plates and a .8 mm aperture 32.2 cm focal length pinhole camera, without mercury.

First, I have a conceptual question that I have been unable to answer even after reading many lippmann papers. When mercury is used as a reflector,it makes sense that the "normal" photo process would not occurr, whereby light passing through the emulsion creates a sort of column of opaque silver; since almost all light is reflected back, only light that creates a standing wave with itself upon reflection will be strong enough to interact with the emulsion, so instead of a column of silver, layers of silver at half-wavelengths are formed. However, when using a gelatin-air interface as the reflector, it seems to me that the relfection is so weak that the majority of light would interact with the emulsion in the same way that it would in a normal black-and-white photograph, passing straight through and leaving a trail of silver seperated from the silver-halide or whatever. Certainly some laminae would occur, but wouldnt they be overpowered by the non-interference effects?

My second question is procedural. I have no idea what kind of exposure lengths I should use. I have read that, especially without mercury, very long exposures are needed, so I have tried, so far, 30 and 40 minute exposures to a still life illuminated both by diffuse florescent lights and an incandescent light, but without any success. What prompted the first question is that when I develope the film, I don't see any opacity at all. I expected to get a black and white negative or something, at least. Clearly, I don't understand whats going on! Anyway, do holographic plates have a property similar to speed in normal film that would infform, along with the amount of light and F-number, the exposure time?

Any help would be much appreciated. If these questions are answered elswhere, please feel free to refer me to a paper or another post or something.
Colin Kaminski

Lippmann Photography and pinhole cameras

Post by Colin Kaminski »

Welcome, first I should say that I have only seen a couple of Lippmanns in person and I have never made one. The transmitted image will show color effects and so will the reflected image. If you are not seeing an image (even though it is the wrong color) in the transmitted image then I think you are underexposing. Somewhere I was able to create an equation that converted uJ/CM^2 into ASA. I seem to remember that PFG-01 was something like 1/1000 ASA! I did this 10 years ago and my memory is pretty shaky on stuff like that. If I find that equation again I will post it here and in the Wiki.
Martin

Lippmann Photography and pinhole cameras

Post by Martin »

Obviously, making Lippmann photographs without a reflector does work. Darran Green makes very nice photos based on such grounds.
One would think though that in “holographic terms” the reflection from the emulsion/air interface would produce a weaker DE, given the far higher beam ratio.

Regarding your exposure time – and this is just a guess – I'd think your 0.8mm aperture doesn't let pass a lot of light. So you might have to increase your exposure time even further.

Are you doing colloidal development?
Ed Wesly

Lippmann Photography and pinhole cameras

Post by Ed Wesly »

I'll say that .8 mm aperture doesn't let in much light! f/# = focal length divided by aperture, so 32.2 cm = 322 mm, so your f/# = 322 mm/ .8 mm = 402! Typical for pinhole photography!

So with a fast 400 ISO photographic film, an f/400 pinhole would require about 1 1/2" expo in bright sunlight. (The Basic Daylight Exposure is to shoot with the lens at f/16 with the shutter at 1/ISO.) Comparing relative intensities of f/#'s is done by (f/#1)^2 / (f/#2)^2. First f/# squared divided by second f/# squared, so in our case, 402^2/16^2 = 631. So with ISO 400 film, the exposure time at f/402 under bright daylight would be 1/400" * 631 = 1.57 seconds!

That's with ISO 400! Colin is in the ballpark with the 1/1000 ISO or .001 ISO of the holographic plates. I had to make some B & W photos on glass for a project, and what would take .1" on photo paper, took 50" on an Agfa 8E75HD plate! So that is off by a factor or 500! And photographic papers are usually regarded as around ISO of 1! My own limited experience with PFG-03M is that it needs about 16 times more light than Agfa 8E75HD or its clone, PFG-01.

If the holo plates are in the range of ISO .001, then BDE following the above guidelines would mean 1000" expo @ f/16, which is > 15 minutes, which sounds kind of right from the literature. So if you need more than 600 times more light at your working f/stop, then exposures would be 150 hours!

Even if my calculations are off by an order of magnitude, still the exposure would be 15 hours. And that's in bright daylight! You've got a mix of artificial light which is nowhere near as bright. My suggestion is to first tune in the exposure time in your pinhole camera using photo paper, and then try shooting the holo plates. Or replacing the pinhole with a lens to get much more light. It sounds like you are way underexposed.

You are correct that the plate should look like a decently exposed negative in the developer. After bleaching, there will be some sort of recognizable image.

The mercury mirror would give greater modulation, and probably would cut exposure time in half, since it's redirecting the light back into the emulsion. Of course there is the mess to have to deal with.

My own viewing experience of Lippmann photos are some at the International Museum of Photography at the George Eastman House, (tests from the Ives Astrophysical Review paper of 1907), some samples Bill Alschuler shows around, some of Hans Bjelkhagen's, and the closest I've been around to their production and samples that I have in my possession are from Jesus Lopez, who built a camera to take meter square Lippmann plates. (He hasn't been able to afford meter square plates yet, just 4 by 5's) It is not an easy beast to tame, and choking off the light to just a trickle using a pinhole just makes it next to impossible.

What size plates are you shooting? A 322 mm focal length lens or pinhole is telephoto even for a 4" by 5" camera.
Ejs12006

Lippmann Photography and pinhole cameras

Post by Ejs12006 »

Thanks for your input guys. I have been working on this furiously for the past week or so. I abandoned pinhole cameras; Initially I was intimidated by the optics involved with lenses, calculating image plans etc. but Then I realized you can very easily make sure the image is focused where you will be putting the plate byoutting a white card there instead, turning all ambiant light off, and making sure a little projection of the object appears in focus on the card.

I do, however, have a few more questions I would like to pose, mostly concerning the use of film instead of plates, as well as using coherent and monochromatic light sources, but I think I will start another topic for that.
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