Thanks. My wife and I were just discussing that!Quote:
Originally Posted by Ray Rogers
PE
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Thanks. My wife and I were just discussing that!Quote:
Originally Posted by Ray Rogers
PE
I assume you mean pyro + ammonia. Yes, since ammonia is an AgX solvent that would be a colloidal (or solution-physical) developer. The problem involved with is ammonia evaporation, which makes the solvent action of this developer very unreliable.Quote:
Originally Posted by R Shaffer
No. Actually their fogging problem, I understand, was mainly caused by inconvenient packaging (I heard they had used formaldehyde treated cupboards)Quote:
Originally Posted by holmburgers
The pre-hardening helps the very soft emulsion survive the processing baths.
Quote:
Originally Posted by holmburgers
Yes, that's also been mentioned in one of the files I put online.
The light source of your projector would have to be carefully chosen, since its spectral composition determines what color range you'll get from your Lippmann photographs.
Ray, I remember the video you recorded when we went to see the Lippmann collection at the Musée de l'Elysée (http://www.elysee.ch/index.php?id=144&L=1) in Lausanne, Switzerland. As you know they have the world's largest collection of Lippmann photographs, I believe some 120 plates by Gabriel Lippmann. Have you been able to digitize that video in the meantime?Quote:
Originally Posted by Ray Rogers
Given the rarity of original Lippmann photographs, your video might be a pretty interesting and unique document - even if the viewing conditions at the museum were far from ideal (fluorescent tubes!!!).
There might exist some diffractive, "holographic" approaches to copying a Lippmann plate.Quote:
Originally Posted by Photo Engineer
Yes, I was referring to the Lumeire Pyrogallol-Ammonia developer. I could not decide which developer would be better, so I ordered both the GP-2 premix and the pyrogallic acid from PF so I could try both. Would a small covered tray help reduce evaporation?Quote:
Originally Posted by Hologram
I had never heard of solution-physical development prior to researching this, pretty fascinating.
Have you tried using glyoxal for hardening holographic plates? That is the hardener I have on hand & was planning to use. PF does sell the 37% formaldehyde solution, but I am going to try an avoid it.
I now have the plates & chemicals on the way to try this experiment out. I'll be sending half the plates on to Chris ( holmburgers ) as he is my 'partner in crime' on this. I am about half way through fabricating a plate holder with large black space behind the plate and should have it finished today. :D
R Shaffer, I'll be curious to know how you modify your film holder. I'm currently running some ideas thru my head, but nothing concrete yet. I'm considering that a typical 4x5" holder isn't thick enough to accommodate black velvet, mat board, etc (even by cutting thru the center divider). Perhaps an old Polaroid back would be "cavernous" enough to allow for easier modification?
What type of developer would GP-2 be classified as and how does it differ from the Lumiere Pyro developer? I'm tempted to try the Lumiere developer first, due to its history with the Lippmann process; I feel some assurance that it's "time tested". However, as Bjelkhagen is using the GP-2 with these modern Slavich materials, there's certainly reason to go with that as well.
I cut the aluminum divider out of a 4x5 film holder. Made a 3 x 4 plate holder out of a manila folder & layered up 4 ply mat board. The manila folder layer resides in the film slot, with the mat board layers built up behind ( 2 layers 4ply seems just shy of 2.5mm ). Your right that it is too thin, so I built a box out of 2 layers of foam core painted with black primer. The whole thing is pretty close to 2" in thickness. I need to stop off at the hardware store & get Krylon Ultra Ultra Flat Black. I guess that is what a lot of the DIY telescope builders use for anti reflective coating. I'll PM some photos. Bjelkhagen used a modified graphmatic film holder, which is pretty deep. My polaroid holder is not deep enough and is made of pressed steel.
The GP-2 is considered a solution-physical developer because of the thiocyanate and the Lumiere from the ammonia. Here is a link on solution-physical developers - http://unblinkingeye.com/Articles/Ph.../physical.html Gets over my head pretty quickly, so maybe someone else will chime in.
Can you post some pictures. I have in mind that an old Graflex film pack holder may be think enough. And since no one makes film packs any more they're basically useless.Quote:
Originally Posted by R Shaffer
Ripping the septums out of a Graphmatic seems kind of a waste if the pack film holder will work.
Just a though. But seeing your pics could help make it make sense.
It is a film pack adapter ( not a graphmatic ) they modified. I am not very familiar with them, so I'm not sure how much they changed it, other than gluing felt to the back. Shoot me a PM and I'll send you the whole paper on making Lippmann Plates. It has a photo of the authors modified film pack adapter along with a whole description & history of the process.Quote:
Originally Posted by michaelbsc