Kodak film speeds in late 1920s to 1940

Discussion in 'Black and White' started by paulc, Oct 17, 2002.

  1. Does anyone know what the ASAs were for Kodak films in the late 1920s
    to 1940? It sounds like film sensitivity increased in 1930, because
    of technical improvements. I'm researching photos in Hawaii during
    this period and find lots of exterior shots but very few interior
    photos. I suspect it may be due to limitations of the film and
    availablility of cameras with flash/bulb connections, however, that's
    only a guess. Anybody want to comment?

    With thanks,
  2. Most early films were orthochromatic, and quite slow, but speed ratings came a bit later, and there were several of them like Weston. See:>>>>www.kodak.com/US/en/corp/aboutKodak/ kodakHistory/milestones78to32.shtml<<<< and also:>>>>www.kodak.com/US/en/corp/aboutKodak/ kodakHistory/milestones33to79.shtml<<<< There are MANY booksand sites dealing with the history of photography.
  3. Thanks very much, Art, the Kodak sites have quite a lot of good information on cameras and even discontinues films, however, not much on early film speeds. It may be as you note, that ASAs came later on. Have also been looking at magazine advertisements for the period with similiar results. Thanks again for your help,
  4. I have a 1940 Kodak Reference Handbook with a film section. The speed numbers are a bit baffling as they give a Kodak number, a Weston number, and a GE number. No idea if the Kodak number is similar to ASA, but they seem too high. Check a conversion table. Here are the numbers in that same order. Panatomic X: 125, 24, 40. Super-XX: 400, 80, 128. Plus-X: 200, 40, 64. Tri-X sheet: 640, 128, 200. Super Panchro Press: 500, 100, 160. They also list slightly higher Weston and GE numbers for "somewhat less dense negatives preferred by many workers". Not sure if any of this is useful or not. Check the Focal Encyclopedia for much more info on speed conversions.
  5. I'm sure that slow film speeds were a factor, along with the natural beauty of outdoor settings in Hawai'i.
  6. David, you've hit on a likely solution: we STILL wander around in dazed wonder and all that rich, thick light probably just smothers any sensitivity of film for speed. Probably ought to invent a filter to take out a little of the island's natural beauty. Ah, well, then it'd be a problem to remember where I put the filter and to use it.

    And, Conrad, thank you very much for your excellent information, the numbers do seem high for ASAs, though I'm prepared to be surprised. I'll check a search engine for "Focal Encyclopedia" and dig some more.


  7. The original ASA numbers were pretty much all within 1/3 stop of the Weston numbers. The early ASA numbers were revised in the 1960's to aproximately double (Plus-X 80 to 160, later revised to 125, Panatomic-X 25 to 40, Tri-X 200 to 400) although for years photo magazines and books said that we could ignore the "safety factor" and get better negatives. Double-X is still marketed as a pro movie film at ISO (ASA) 250.

    European films were rated DIN and American films used the ASA system. The two systems were then combined, and for awhile they carried dual numbers: Tri-X 400/27 as an example. Eventually everybody all over the world agreed on one standard called ISO. They used the ASA number and called it ISO. Just as well because DIN and ASA actually didn't measure the same thing. ASA was based on the straight line portion of the H&D curve. DIN measured how much exposure was required to achieve a certain density above base density.
  8. From various Kodak publications of the period, recommended exposures in the 1920's on "normal" film would indicate a "modern" ASA rating of 25-50 with normal developement. The sensitivity of generally available films seems to have increased in the early 1930's and higher speed emulsions became also available.
  9. You'll have a bit of difficulty exactly matching early speed numbers with the current ISO method.<br>Speed-testing methodologies were changed several times (not sure exactly when, I'd have to look it up) before arriving at the present 0.1D over B+F as the speed point.<p>Before that, the speed point was variously taken as the intersection of the projected curves of differing gammas, or the point at which a *just perceptible* density above B+F was found, along with various methods of establishing the contrast index, gamma, or bar gamma of the film curve. The 'average scene' brightness range was variously taken as being represented by a 20:1, or a 32:1 illuminance range at the film plane as well.<p>In view of this mish-mash of changing measuring parameters, it's a wonder that there's any relationship at all between ISO speeds and the old H&D, Watkin's, Weston, ASA, DIN, and other assorted ratings that abounded in the time between the two world wars.
  10. Looks like 4400 H.D. film speed in 1936 was roughly equal to asa/iso 50 .<BR><BR><IMG SRC="http://www.ezshots.com/members/tripods/images/tripods-261.jpg">
  11. Well I've got a copy of Weston's "Film Ratings Fall-Winter 1946"

    Super XX 100 in daylight. 64 tungsten

    Plus X 50 " " 32

    Super Ortho Press 100 daylight 32 tungsten

    Verichrome 50 daylight 32 tungsten

    All Weston numbers not ASA.

    Press films are higher. Starting at 100.

    They also list plates and they start at 6 for daylight some are only 1 with tungsten.

    The other thing is film is only half the issue. Did lens get faster?

    One final thing. If I was in Hawaii I'd have mostly outdoor pictures to-))
  12. My heartfelt thanks to Kelly, Pete, Chris and Al (and anyone else I've mistakenly missed) for all your contributions.

    First, Kelly, thanks for the great photo, it looks like indoor portraits were meant to be shot at 1/5 to 1/10th at 3.5 and it got worse from there if you wanted more depth of field. You're right, the lenses weren't very fast, at least not the 1937 Kodak Vollenda (with a 3.5 lens or 4.5 lens) or the Kodak Six-16 which came with either a 4.5 or a 6.3 lens.

    I'll need to educate myself to understand more about the conversions, or rather, the lack of conversions. I feel like I've barely scratched the surface, my thanks to each of you.

    This question came out of preservation research, I've been looking for late 1920s to 1940 interior photos showing lighting fixtures used in HI so we can restore several employee quarters built in that time period here in Hawaii Volcanoes National Park. After fruitlessly looking in the obvious places (arch drawings, photos in our own archives and building completion reports) I moved on to local magazines, books by period photographers and so on to look for photos of light fixtures. Of course, lots of outdoor photos and an almost complete lack of indoor photography--except by professionals for advertising and by the very wealthy who could afford the tools.

    I've found enough examples of period lighting fixtures now to recommend what is appropriate for "our" quarters and chose from various catalogs. Could have gone to the catalogs first, however, these quarters were built by the C.C.C. so they're special, and light fixtures available here weren't necessarily from the continental USA.

    Finally, in Jauanary 1942, the military governor banned photography of coastlines, harbors, installations, military machinery and tools, photography from airplanes, Etc. so the pros went into portraiture and everybody else put their cameras away for the duration.

    Again, thanks to each of you for your help.

  13. If you haven't already, you should send an e-mail
    to Scott Hulett at The Surfer's Journal. They are
    really dialed in to early (1920s-1940s) historical
    photographs from Hawaii and California, and may be able
    to provide you with some leads/ideas/contacts.
    Think their URL is www.surfersjournal.com
    Best wishes!
  14. There was also an approximate two stop safety factor incorporatated
    into the ASA standard of 1943. It was later reduced and then almost
    eliminated in 1960. So, a 200 speed film in the forties would be a
    400 or 800 speed film today without any changes to the film. It's
    hard to do an apple to apple comparison between films then and now.

    Before the ASA standard in the 40s, there were a number of different
    methods of determining film speed.
  15. Thw film speed safety factor I remember was 1 stop; thus tri-x went from asa 200 to 400; with no change in emulsion. The newer asa definition I remember was around 1960 ish IKE/Robert? .. It defines the speed point as 0.1 above gross fog.
  16. According to Jack Dunn in "Exposure Manual", the safety factor
    was reduced to about 2.5 in the 1955/57 revision of the standard.
    According to C.N. Nelson in "Safety Factors in Camera Exposures",
    Photographic Science and Engineering 1960, the safety was somewhere
    between 2 and 4, but says, "It is a remarkable fact that the exact
    size of the safety factor has not been definitely known." While I
    stated it could have been 4 prior to the reduction to 2 or more
    accurately 2.5, then to the present value of 1.2, I might have been
    confusing it with the average flare factor of 4.0 in the 40s, however,
    there is an indication that the safety factor may have been larger
    than 2.5 prior to 1955/57. How much is anyones quess according to
    Nelson. But from a paper by Loyd A. Jones, "The Brightness Scale of
    Exterior Scenes and the Computation of Correct Photographic Exposure,"
    Journal of the Optical Society of America 1941, Jones talks about a
    safety factor of 2.5. So, there seems to be some difference of
    opinion between some of the great photographic theoreticians.
    I find it strange that Nelson didn't remember Jones' statement in
    his seminal paper. Nelson worked if not with Jones directly, then
    with H.R. Condit who worked directly with Jones (Condit did the actual
    experiments and later took over for Jones when Jones retired).
    Was Dunn referring to a change in 1955/57 or was he remembering
    the confirmation of the 2.5 factor in Nelson's paper? In any case, in
    1960, the factor did changed from 2.5 to 1.2 and film speeds did
    double. It appears that the safety factor of the ASA standard in the
    1940s is in some question.

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