B
Ben Fullerton
[Rather long, but difficult to express clearly in a few lines.]
I have several thousand slides, a few hundred of which are over fifty
years old. 90% or more of the old ones are Kodachrome (ASA 25, I think)
and the remainder are Ektachrome.
We also have a few commercial slides of unknown emulsion which were
purchased from souvenir shops about fifty years ago.
The question of 'image stability' has been discussed here on what reads
like a very high tech level. I would like to get back to the basics - and
ask a few questions about the point of all this discussion.
First - my personal experience with the emulsions of the 1950s:
Kodachrome, properly stored (as defined by Kodak - dark, cool, dry), and
with an estimated total projection time of less than 10 minutes (no single
projection of over 30 seconds), has no changes visible to the human eye
(the only really important detail?) after 50 years.
Ektachromes from that period, with identical storage and use, have shown
slight visible shift of some colors.
The unknown emulsion purchased slides are useless except maybe for
conversion to 'grayscale' images, ad even then will probably require
contrast enhancement post-scanning.
As Kodachrome has a totally different chemistry as compared to all other
color slides (unless I am not up to date on changes of the past ten or
fifteen years), are the new slide films - which are claimed to be superior
in life span to Kodachrome - using yet another totally different emulsion
chemistry?
As for color fidelity - One of the faculty members (often referred to
locally as "the wizard) that I had frequent contact with during my years
as a Physics Technologist (Dalhousie University) was involved in a project
for the Dal. medical school which involved color fidelity.
In approximately the 1970s or 1980s, with all of the color films available
then and color tv (CCTV), there were major problems in generating images
that were acceptable for medical instruction purposes - where, for
example, even slight color shifts of internal organs were critical to
correct understanding of their condition.
Back in the more common world of family, travel, and advertising image
reproduction, it was generally understood that color film was incapable of
reproduction of the full detail of colors found in nature - or if you
like, the full color spectrum of visible light.
Kodachromes were recognized as favoring reddish hues, and therefor more
favorable for 'people' photos. Ektachrome and most others of the day were
seen as favoring blues to some extent - great for scenics.
For the average user, both then and now, I feel that the important thing
is not the absolute maintenance of the original photo colors and balance,
but the preservation of an image that looks 'natural' to the viewer. As
seems so important to some, how do you preserve the original subject
matter to ensure that there is zero shift in this comparison standard?
Yes, I understand that it is probably easy to have a set of laboratory
standard colors with long term stability, but the question here seems to
be more on the line of our everyday surroundings - people, clothing,
buildings, nature scenes from forests to beaches, city scenes, etc. etc.
Bottom line for many of us - does the photo look natural?
If it does, why are some so hung up on the fact that the shade of the red
car (or dress or house) - that was recorded imperfectly by the film when
the photo was taken - has shifted by some trivial amount in the five or
fifty years since the photo was taken?
Am I that far out to lunch in just wanting natural looking digital
reproduction of something that I saw and photographed fifty years ago?
For anyone that has read this far - thanks for your patience in hearing me
out.
Ben Fullerton - Photography enthusiast for over 60 years.
I have several thousand slides, a few hundred of which are over fifty
years old. 90% or more of the old ones are Kodachrome (ASA 25, I think)
and the remainder are Ektachrome.
We also have a few commercial slides of unknown emulsion which were
purchased from souvenir shops about fifty years ago.
The question of 'image stability' has been discussed here on what reads
like a very high tech level. I would like to get back to the basics - and
ask a few questions about the point of all this discussion.
First - my personal experience with the emulsions of the 1950s:
Kodachrome, properly stored (as defined by Kodak - dark, cool, dry), and
with an estimated total projection time of less than 10 minutes (no single
projection of over 30 seconds), has no changes visible to the human eye
(the only really important detail?) after 50 years.
Ektachromes from that period, with identical storage and use, have shown
slight visible shift of some colors.
The unknown emulsion purchased slides are useless except maybe for
conversion to 'grayscale' images, ad even then will probably require
contrast enhancement post-scanning.
As Kodachrome has a totally different chemistry as compared to all other
color slides (unless I am not up to date on changes of the past ten or
fifteen years), are the new slide films - which are claimed to be superior
in life span to Kodachrome - using yet another totally different emulsion
chemistry?
As for color fidelity - One of the faculty members (often referred to
locally as "the wizard) that I had frequent contact with during my years
as a Physics Technologist (Dalhousie University) was involved in a project
for the Dal. medical school which involved color fidelity.
In approximately the 1970s or 1980s, with all of the color films available
then and color tv (CCTV), there were major problems in generating images
that were acceptable for medical instruction purposes - where, for
example, even slight color shifts of internal organs were critical to
correct understanding of their condition.
Back in the more common world of family, travel, and advertising image
reproduction, it was generally understood that color film was incapable of
reproduction of the full detail of colors found in nature - or if you
like, the full color spectrum of visible light.
Kodachromes were recognized as favoring reddish hues, and therefor more
favorable for 'people' photos. Ektachrome and most others of the day were
seen as favoring blues to some extent - great for scenics.
For the average user, both then and now, I feel that the important thing
is not the absolute maintenance of the original photo colors and balance,
but the preservation of an image that looks 'natural' to the viewer. As
seems so important to some, how do you preserve the original subject
matter to ensure that there is zero shift in this comparison standard?
Yes, I understand that it is probably easy to have a set of laboratory
standard colors with long term stability, but the question here seems to
be more on the line of our everyday surroundings - people, clothing,
buildings, nature scenes from forests to beaches, city scenes, etc. etc.
Bottom line for many of us - does the photo look natural?
If it does, why are some so hung up on the fact that the shade of the red
car (or dress or house) - that was recorded imperfectly by the film when
the photo was taken - has shifted by some trivial amount in the five or
fifty years since the photo was taken?
Am I that far out to lunch in just wanting natural looking digital
reproduction of something that I saw and photographed fifty years ago?
For anyone that has read this far - thanks for your patience in hearing me
out.
Ben Fullerton - Photography enthusiast for over 60 years.