Thank you for this perspective. I've always suspected some historical context was involved.
Thank you for this perspective. I've always suspected some historical context was involved.Bear in mind that, at the time Adams popularized this stuff, there wasn't a lot of rigor around photography. It was a lot of secret sauce and stories around the campfire. He sought to systematize things so that a given photographer could arrive at repeatable and useful results for themselves, not set some absolute standard of accuracy.
The target densities for pre-1960 negatives reflected a desire for more exposure.
By 1960, it had become clear that those targets were not optimum for the current films and many modern lenses.
When they changed the speed numbers, the densities were effectively reduced - both when using meters, and sunny 16.
My understanding was also that prior to 1960 most cameras/people did not have light meters and were estimating exposure. There was more danger of underexposure in those circumstances. Meters were becoming more common in the 60's and exposure could be determined more accurately than previously. Thus the need for the safety factor could be removed and the film speeds increased.
The change had nothing to do with the film, but with the rise of more accurate metering.
chuckroast, wow my reply to you about Richard Coppnow's article and what may have been a useful discussion on it seems to have been succeeded in my absence by another vigorous exchange. Not that I am against this per se but can I say that I am still e interested in your answers to my questions and your comments on my what to me seems some puzzling statements by Richard
Just in case this appears to you to be me "piling in with the rest of those responding" I am just looking for what your comments are. I need to say for the sake of being open that I may have further questions depending on where what you say leads to
Thanks
pentaxuser
When I'm making exposures, I actually visualize in my mind the actual shape of the film curve itself, and at what point I want the shadow placement relative to that specific curve, with its specific anticipated development. I do it almost automatically, based on both a background in plotting density curves of many types, and also sheer experience. I neither need nor want any kind of calculation (that too is in the rear view mirror). I still keep a simple math calculator in my equipment drawer with log functions, but rarely need it. So in my case, the Zone System as sometimes quantified is just too complicated, yet at the same time, not specific enough. I do understand it. But I don't need my ashes to be launched into space in a silver DeLorean by a nutty professor who looks exactly like Minor White.
I cannot speak for him (I don't know him personally) but his description of what happened and why is consistent with my own understanding. It's certainly true that we could both be wildly wrong. To the best of my understanding, "ASA" doubled overnight when the new standard was adopted, even though the films had not changed a bit. Notionally, it was like they went from measuring actual gas mileage to EPA estimates.
What isn't wildly wrong is the direct evidence that I have seen that the majority of people exposing monochrome at box speed and then developing in the ordinary manner, are getting thin negatives ... well, that's not quite true. They may be getting decent negatives, but they are missing shadow detail far too often. As just one example, look at the images posted by the OP when they kicked off this thread. Shadow detail is minimal or even completely missing.
I hope I have not come across as strident or doctrinaire about any of this stuff. People should use whatever gives them the images they like. I just have done a ton of my own testing and reached the conclusions offered here. Feel free to ignore me - certainly most people in my social orbit do
Chuck - well it's certainly refreshing to know that you and I perceive the same flaw in the compression model of the Zone System, even though we are addressing it in different manners. If I need a heavier-handed treatment, instead of going down the minus-development rabbit-hole, I'm more likely to go ahead and give normal development for sake of full tonal richness, but then add a selective contrast mask which brings out all the microtonality (rather then suppressing it by stomping on the peanut butter sandwich to make it flatter, which the ZS prescribes).
But your descriptions of glacial pace development have at least piqued my interest; and one of these days I'll probably experiment with it myself, if only out of curiosity.
I've only done a little experimental printing with ACROS II so far, some involving moderate contrast scenes like the one you posted, others excessive contrast even on the same roll, just to see what one can get away with in comparison to previous Acros. But generally I shoot TMax 100 in 120 film instead, due to its exceptional SBR capacity. For this afternoon I've got TMY 400 in the 6X9 rangefinder instead, for sake of a brisk walk, with the tripod potentially left at home. We're well north of any anticipated landfall of scary hurricane Hillary, but might get a little rain anyway.
Chuck - well it's certainly refreshing to know that you and I perceive the same flaw in the compression model of the Zone System, even though we are addressing it in different manners. If I need a heavier-handed treatment, instead of going down the minus-development rabbit-hole, I'm more likely to go ahead and give normal development for sake of full tonal richness, but then add a selective contrast mask which brings out all the microtonality (rather then suppressing it by stomping on the peanut butter sandwich to make it flatter, which the ZS prescribes).
But your descriptions of glacial pace development have at least piqued my interest; and one of these days I'll probably experiment with it myself, if only out of curiosity.
I've only done a little experimental printing with ACROS II so far, some involving moderate contrast scenes like the one you posted, others excessive contrast even on the same roll, just to see what one can get away with in comparison to previous Acros. But generally I shoot TMax 100 in 120 film instead, due to its exceptional SBR capacity. For this afternoon I've got TMY 400 in the 6X9 rangefinder instead, for sake of a brisk walk, with the tripod potentially left at home. We're well north of any anticipated landfall of scary hurricane Hillary, but might get a little rain anyway.
I have been part of pure-silver since its inception. I find Knoppow's many postings incredibly insightful. He may be skipping a few steps in doing the proof here, but I'd encourage you to go through the pure-silver archives and see the many useful contributions he's made. He's sort of a walking encyclopedia of this stuff.
My understanding was also that prior to 1960 most cameras/people did not have light meters and were estimating exposure. There was more danger of underexposure in those circumstances. Meters were becoming more common in the 60's and exposure could be determined more accurately than previously. Thus the need for the safety factor could be removed and the film speeds increased.
The change had nothing to do with the film, but with the rise of more accurate metering.
If memory serves, (best check the archives, though), I believe PE stated that he exposed Kodak films at 1/3 to 2/3 stop over as a rule for best results. He was, of course, intimately engaged in the design and production of Kodak films.
We need to be careful not to conflate exposure with speed.
I have to assume that in his sharing his behavior to get best results with Kodak films, he was downrating the ISO when programming his exposure meter. That would be a speed modification.
Also, I believe he shared the information as practical matter to achieve real world results, not impugning the scientific method.
He did share the recommendation as a practical matter, but not as film speed. Film speed is a way to sensitometrically evaluate different films so they equate to a psychophysically determined level of quality. It doesn't suggest the film speed must be strictly adhered to but uses it as a way to compare film emulsions equally and consistently. Film speed purposefully uses a limiting variable in order to express the usable range. A photographer is free to make adjustments based on personal preference and aesthetics; however, don't forget film speed relates to the results from controlled tests using people to judge perceived excellent results. The data from the tests does show a slight change in the perception of quality with additional exposure which could be attributed to a problem with the judges actually being able to perceive a change in quality with the additional exposure. Up until the first excellent print choice, the ordering of the prints from the judges were consistent. After that point, the print order was not.
An example that might help the concept of film speed vs exposure has to do with the pre 1960 ASA speed being an EI. The actual speed was determined at the fractional gradient point. A constant was then applied which has come to be known as the safety factor.
The fractional gradient speed is 1/Es. This can be considered the actual film speed. k then is applied creating an EI for the film. This is no different than changing the speed setting on a camera or exposure meter. It doesn't change the speed of the film. It only adjusts how the photographer exposes it.
View attachment 347063
For example, if Es = 0.0032 mcs, the fractional gradient speed would be 312. Applying k makes the EI 78. Under the conditions of the current ISO standard, the fractional gradient point falls around 0.30 log-H below the 0.10 fix density speed point. Based on that and using the ISO speed equation, Film Speed = 0.8 / Hm, the current speed for the same film would be 125. Since the current ISO speed uses the Delta-X Criterion which continues to use the fractional gradient speed as a basis, the current ISO speed can technically be considered an EI. The fractional gradient speed point was never intended to be used as the applied film speed, but a point where film speed is determined.
tl;dr A lot of ink is spilled on "What is the REAL ASA?", but it simply doesn't matter. The real question is, "What is YOUR ASA?"
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