Archived posting to the Leica Users Group, 1999/12/22
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Fellow Leicaphiles,
The following post and news item was sent to PhotoForum by Prof. Andrew
Davidhazy of RIT. It speaks for itself.
Best,
Bob
ABCNEWS reports:
Scientists say they have found a way to produce photographic film that
is 10 times more sensitive to light - an advance that could make
true-to-life pictures of candlelight dinners possible without a flash or
muted colors.
Agfa, the European film manufacturer that sponsored the study and holds
the patent, would not comment on when the film might become available
commercially. And researchers acknowledged more work is needed to
determine how well it can reproduce certain colors.
But if the approach works, it could revolutionize photography, improving
on the basic design that has been around since the 1840s.
All Available Light
In a study published in Thursday's issue of the journal Nature,
researchers at the University of Paris-Sud said they have managed to
capture every bit of available light on film by adding a simple
chemical.
"A real breakthrough," said Richard Hailstone, a scientist at the
Rochester Institute of Technology.
A camera focuses light from an object onto film, which is made of
plastic with a chemical layer. The film uses two kinds of
light-sensitive crystals - halide crystals and silver crystals - to
produce an image.
When a bit of light, called a photon, strikes one of the halide
crystals, it breaks an electron loose. Ideally, that electron combines
with a nearby silver crystal.
Picked Up Electrons Recorded
Later, when the film is placed in a developer, the silver crystals that
picked up electrons darken and stick to the plastic while the rest are
washed away. The result is a negative.
One photon of light cuts loose one electron, but most of the time the
electron quickly returns to the halide instead of combining with the
silver. As a result, most film is not very efficient. In dim light, long
exposure times are needed to capture enough photons to create an image.
The French researchers added a chemical called formate to the crystals.
That kept the loose electrons from recombining with the halide crystals.
So every electron knocked loose by a photon was captured by a silver
crystal.
Other Options Ruin Film
Other chemicals can keep electrons from recombining with the halide
crystals, but they ruin the film's ability to produce an image.
The chief researcher, Jacqueline Belloni, said her technique could be
used to make images with greater clarity or to take pictures in very low
light without a flash.
The new film could also widen the gap in picture quality between
conventional photography and no-film digital photography, which has been
growing in popularity.
One remaining question is how the technique will work in with dyes that
allow film to record red light, Hailstone said. Belloni said further
research will have to look at the question.
Researchers at Eastman Kodak Co. said they have been experimenting with
chemicals that do the same thing that formate does. They said it may be
hard to make commercial film with formate.
- - this bit of photographic chemistry news brought to you by a davidhazy -
(kind of a loose description of the exposure/development process no?)
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Date: Wed, 22 Dec 1999 15:46:27 -0500 (EST)
From: ADavidhazy <ANDPPH@ritvax.isc.rit.edu>
Subject: Film Improvements Possible Announced by Agfa
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ABCNEWS reports:
Scientists say they have found a way to produce photographic film that
is 10 times more sensitive to light - an advance that could make
true-to-life pictures of candlelight dinners possible without a flash or
muted colors.
Agfa, the European film manufacturer that sponsored the study and holds
the patent, would not comment on when the film might become available
commercially. And researchers acknowledged more work is needed to
determine how well it can reproduce certain colors.
But if the approach works, it could revolutionize photography, improving
on the basic design that has been around since the 1840s.
All Available Light
In a study published in Thursday's issue of the journal Nature,
researchers at the University of Paris-Sud said they have managed to
capture every bit of available light on film by adding a simple
chemical.
"A real breakthrough," said Richard Hailstone, a scientist at the
Rochester Institute of Technology.
A camera focuses light from an object onto film, which is made of
plastic with a chemical layer. The film uses two kinds of
light-sensitive crystals - halide crystals and silver crystals - to
produce an image.
When a bit of light, called a photon, strikes one of the halide
crystals, it breaks an electron loose. Ideally, that electron combines
with a nearby silver crystal.
Picked Up Electrons Recorded
Later, when the film is placed in a developer, the silver crystals that
picked up electrons darken and stick to the plastic while the rest are
washed away. The result is a negative.
One photon of light cuts loose one electron, but most of the time the
electron quickly returns to the halide instead of combining with the
silver. As a result, most film is not very efficient. In dim light, long
exposure times are needed to capture enough photons to create an image.
The French researchers added a chemical called formate to the crystals.
That kept the loose electrons from recombining with the halide crystals.
So every electron knocked loose by a photon was captured by a silver
crystal.
Other Options Ruin Film
Other chemicals can keep electrons from recombining with the halide
crystals, but they ruin the film's ability to produce an image.
The chief researcher, Jacqueline Belloni, said her technique could be
used to make images with greater clarity or to take pictures in very low
light without a flash.
The new film could also widen the gap in picture quality between
conventional photography and no-film digital photography, which has been
growing in popularity.
One remaining question is how the technique will work in with dyes that
allow film to record red light, Hailstone said. Belloni said further
research will have to look at the question.
Researchers at Eastman Kodak Co. said they have been experimenting with
chemicals that do the same thing that formate does. They said it may be
hard to make commercial film with formate.
- - this bit of photographic chemistry news brought to you by a davidhazy -
(kind of a loose description of the exposure/development process no?)
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