Lippmann Process - a 19th Century process, a 21st Journey

[hudsonvalleygiclee]

I have frequented this site on and off for information and have posted very little. I am going out on a limb by posting this, but I will anyway. Before I go on, I really don't want to hear any of the "its impossibles" or "dont waste your times." If all else fails, I have learned something.

My knowledge of film photography is extremely limited. I recently took a trip to Rochester NY and went to the Eastman House. My interest was to see the first color photograph of a landscape; taken by Louis Ducos du Hauron in 1877. I wasnt able to see it in the main gallery and set up a meeting with the head Archivist. I did so and was able to see the photograph first hand, among others.

A 19th century process specialist was so kind to discuss all he knew of the processes of the time. He went on to talk to me about numerous process including the Lippmann process. Since he talked to me, I have been on a knowledge hunt to discover more.

This is what I know about the process (provided by Mark the Specialist):
Lippmann plates are still the only natural color photograph and they are permanent.
The image is virtual since it relies on viewing with full spectrum light to see the colors.
The plates are made on glass using a panchromatic emulsion that is very thin.
The plates are held in a special plate holder that allows the light entering the camera to go through the glass support first, then through the thin emulsion. The holder is also designed to hold liquid mercury in contact with the surface of the emulsion.
During the exposure the light exposing the emulsion reflects off the mercury interface and then exposes the emulsion a second time 1/2 wavelength from the first, causing an interference effect on the emulsion.
After the exposure the mercury is drained from the holder and the plate removed.
When the plates are processed (conventional black and white chemistry) the final image looks like a negative, but when placed against a prism and illuminated with natural light...the image can be seen in natural colors...not by pigments or dyes...but by the natural spectral colors.

That is what I know. I want to know more. So here are some questions to you, the APUG community:

What is panchromatic emulsion and how thin is thin?
The plate holder explained above, how does one believe it was designed.
It was stated the emulsion was in contact with Mercury. Is the mecury separated from the emulsion by a pane of glass (that would allow you to photograph horizontally). If so, would a glass or plexiglass casing prevent or slow down light as it passes through, enough to thwart the process from working?
Any links about b/w developing chemistry would be great.

Again, please realize I am here on a novice level trying to weave through all of your minds to learn something. I am twenty four years old, own/operate a fine arts printing business, and use digital photography for many reasons from fine art work capture to model work to personal fine arts. I consider myself a professional and I want to learn more about the processes of yesteryear. Any links, books (reading material), words of advice is greatly appreciated. Thanks to all who can assist.

 

[cowanw]

The first hit on google says the mercury is in contact with the back of the photographic plate and the emulsion is 10 wavelengths thick.
The third hit is an original paper.
I am sure there is a great deal of info on the internet to get started.
Also maybe the Nobel organization has files about Lippman's nobel prize.
Be sure to let us know how you get on.

 

[yellowcat]

This is what G Attridge & H J Walls have to say about the Lippmann process in 'basic photo science'


The only direct process which has ever been made to work was invented in Paris by Gabriel Lippmann in 1891. A Lippmann photograph is made by exposure on a very fine-grained emulsion backed by a reflecting layer in intimate contact with it. In practice, a plate with its emulsion immersed in a pool of mer*cury is exposed through the back. Rays of light traversing the emulsion are reflected, at the emulsion-mercury interface, back along their initial path. In this way a series of stationary waves
with nodes (points of no amplitude) and anti-nodes (points of maximum amplitude) is set up; that is, what is technically known as interference occurs.
At the anti-nodes light acts and silver is subsequently formed in development; at the nodes, which are points of no amplitude and at which there is con*sequently no light, no exposure occurs, and no silver is sub*sequently formed. The processed emulsion therefore contains exceedingly thin laminae of silver separated by a distance equal to half the wavelength of the light which produced them. This distance necessarily depends on the colour of the light, and will be greatest in a red part of the image and least in a violet. On viewing the processed emulsion by reflection in white light, the reverse process occurs; the interference colours seen depend on the separation of the laminae, and therefore on the colours of the original image; these last are in fact reproduced in this way.
Incidentally, a difficulty in understanding the process which no one ever mentions is that of envisaging what happens when the incident light is spectrally impure—i.e., can be resolved into a wide range of wavelengths—as is the light from most coloured objects. How far apart shall the laminae of silver be found in this case? We can only say that this difficulty is just "one of those things" which inevitably arise when we try to fill in the details of a physical picture of something whose reality can only be expressed completely by mathematical abstractions.
The idea of the Lippmann process is elegant and attractive, and excellent photographs have been made by it. But not often; the practical difficulties and disadvantages are formidable. True, ingenuity might be able to replace by something simpler the special dark slide and supply of mercury necessary. But other drawbacks would remain: the finished reproduction must be viewed from Just one direction if its colours are to be seen properly; irregularities in processing may lead to the spacing of the silver laminae the finished product not being identical with that of the original stationary waves, which will of course falsify the colours; and emulsions sufficiently fine grained to record these stationary waves are necessarily so slow that exposures run into many minutes in bright sunlight.

 

[hudsonvalleygiclee]

Thanks for the response. I plan on making this post a center for my research. I understand this could be a time consuming endeavor to either just learn or produce something, but I feel its worth the time. This is what I have gathered thus far:

Nobel Prize Lecture:
To start, the lecture made clear some prior research that led up to his work. That section was limited which makes me believe there were no clues or significant factors that should be further examined prior to him. For the plate, this was explained;

a plate is covered with a sensitive transparent layer that is even and grainless. This is placed in a holder containing mercury. During the take, the mercury touches the sensitive layer and forms a mirror.

The lecture goes on to explain post capture but I think its wise to focus on that plate itself for now. Further in the article are some clues to the transparent layer that is even and grainless;

I got quite good results from protein plates. Later, Valenta in Vienna and the Lumieres at Lyons found means of coating the plates in grainless gelatine, sufficiently isochromatic and very much better than the protein plate. Dr Neuhauss in Berlin carried isochromatism to perfection.

As stated, he seemed to have something in the works, but the later names help refine the process for him. I think those names are the isochromatism will be researched.