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ZorkiKat actually the ISO speed can be equated to its sub-components which do have a much longer history. ASA/BS and DIN. an ISO 100/21° is in fact 100ASA/BS 21°DIN, these aren't an equivalent because they are exactly the same. In the early 60's the ASA/BS system changed doubling the film speeds, the DIN system was always more accurate for practical use.
Ian
Tri-x goes back to WW2 in sheet film; something that the Kodak historians fail to grasp. It is in their own Kodak databooks of the WW2 period as an asa of 200 daylight; 160 in Tungsten in 1945. Roll film tri-x; and trix the breakfast food came out on 1954; maybe the Kodak historians ate too much trix; and lost a decades worth of history. Super-XX was the fast roll film before 1954; then tri-x in roll film came out. Super-XX lived on for many more decades
Any film emulsion when coated on paper support, will give at least 1 stop in speed from back reflection and another stop from the high coated silver level. In actuality, the 3000 speed film was about 800. Kodak had a 3000 speed instant product ready to go when they lost the lawsuit to Polaroid and it was never introduced.
Kodak does indeed indicate that their 3200 film is only very pushable, but then the same is true of the Ilford product. Neither have a true 3200 speed. The highest practical speed is about 800 - 1000 due to keeping. The highest true film speed ever achieved was 25000 and that was done two ways at Kodak. The second was recent, and posted on APUG, the first was only done internally. Keeping on the first material was extremely poor and on the second is unknown as it was only created for lab speed tests.
PE
I am curious about the history of Emulsion speeds.
What was the iso of the first commercially available film? was it 8 or 12iso? and from this starting point what were the next speeds available and who reached the benchmark for fastest films of their day?
Who was first to make 32iso film? first to reach the 50mark? first to 100?, 200?, 400?, 800?, 1600? 3200? what companies reached the highest iso's first? and when did they do it? Also what were the benchmark products which broke the speed barrier called?
IIRC they identify it as an ISO 1000 film.
Member Gigabitfilm once tried to estimate the speed of the Kodak NO.1 Camera System and he assumed a speed of 50 ASA.
(To my understanding he used different films in the camera and compared shadow detail of the resulting prints with prints of the time.)
Polaroid made a 20,000 speed film: Dead Link Removed; it was designed for CRT reproduction. I have no idea what its keeping properties were like, although I imagine they would be pretty bad. I also don't know what the EI is, but I suspect it would be pretty close to the rated speed as you can't really push Polaroid films the same way as you can with normal films.
Member Gigabitfilm once tried to estimate the speed of the Kodak NO.1 Camera System and he assumed a speed of 50 ASA.
(To my understanding he used different films in the camera and compared shadow detail of the resulting prints with prints of the time.)
C'mon Ian, we did a lot of hand-held Kodachrome 35mm shots that were taken at ASA 10.
PE
Note I said "more practical" Ron, but a 10 ASA film in a pre-war hand held roll-film or sheet film camera with a typical lens of max aperture f4.5-f5.6 would be pushing things . . . . except on very bright sunny days
Ian
Note I said "more practical" Ron, but a 10 ASA film in a pre-war hand held roll-film or sheet film camera with a typical lens of max aperture f4.5-f5.6 would be pushing things . . . . except on very bright sunny days
Ian
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