Lippmann plate
Encyclopedia
Gabriel Lippmann
Jonas Ferdinand Gabriel Lippmann was a Franco-Luxembourgish physicist and inventor, and Nobel laureate in physics for his method of reproducing colours photographically based on the phenomenon of interference....
conceived a two-step method to record and reproduce colours, known as:
- direct photochromesPhotochromyPhotochromy is the art or process of reproducing colors by photography.[Note] Not to be confused with Photochromism . See Photochromism...
, - interference photochromes,
- Lippmann photochromes,
- Photography in natural colours by direct exposure in the camera
- Lippmann process of colour photography.
A Lippmann plate is a clear glass plate (having no Anti-halation backing
Anti-halation backing
An anti-halation backing is a layer found in most photographic films. It is usually a coating on the back of the film base, but sometimes it is incorporated between the light-sensitive emulsion and the base. The light that passes through the emulsion is absorbed by the anti-halation layer...
), coated with an almost transparent (very low silver halide content) emulsion
Emulsion
An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...
of extremely fine grains, typically 0.01 to 0.04 micrometres in diameter.
Consequently, Lippmann plates have an extremely high resolving power exceeding 400 lines/mm.
Method
In Lippmann's method a glass plate was coated with a "grainless" (ultra fine grain) colour-sensitive film using the Albumen ProcessAbel Niepce de Saint-Victor
Claude Félix Abel Niépce de Saint-Victor was a French photographic inventor. An army lieutenant and cousin of Nicéphore Niépce, he first experimented in 1847 with negatives made with albumen on glass, a method subsequently used by the Langenheim brothers for their lantern slides...
containing potassium bromide, dried, sensitized in the silver bath, washed, flowed with cyanine solution, dried and then brought into optical contact with a reflection surface; the back of the plate is then flowed in a plate holder of special form with pure mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
and exposed in the camera through the glass side of the plate, so that the light rays which strike the transparent light-sensitive film, are reflected in themselves and create interference phenomena of stationary waves
Standing wave
In physics, a standing wave – also known as a stationary wave – is a wave that remains in a constant position.This phenomenon can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling...
. The standing waves cause exposure of the emulsion in diffraction patterns. The developed and fixated diffraction patterns constitute a Bragg condition in which diffuse, white light is scattered in a specular fashion and undergo constructive interference in accordance to Bragg's law. The result is an image having very similar colours as the original using a black & white photographic process.
For this method Lippmann won the Nobel Prize in Physics in 1908.
The colour image can only be viewed in the reflection of a diffuse light source from the plate, making the field of view
Field of view
The field of view is the extent of the observable world that is seen at any given moment....
limited, and it cannot be copied. The technique was very insensitive with the emulsions of the time and it never came into general use. Another reason Lippmann's process of colour photography did not succeed can be found in the invention of the autochrome plates
Autochrome Lumière
The Autochrome Lumière is an early color photography process. Patented in 1903 by the Lumière brothers in France and first marketed in 1907, it was the principal color photography process in use before the advent of subtractive color film in the mid-1930s....
by the brothers A. and L. Lumière.
Lippmann photographic techniques are being developed to produce images which can easily be viewed, but not copied, for security purposes.
Other sources of Lippmann plates
- Kodak Spectroscopic Plate Type 649-F is specified with a resolving power of 2000 lines/mm.