Bill, please let me claryfy I never thought Lachlan was arguing with me, and I appreciate his posting veré and hace learned from him for years... And it was more than 20 years ago when I first taught someone the clear differences between ISO and EI... Quite simple definitions... And I'm not being pedantic... I just don' believe in ISO because It stopped being a standard, it's not a unified concept... They started saying 200 and D-76, then they all had a chat 60 years ago and decided to say 400... Then Kodak made TMax but for Xtol and other speed enhancing developers... Then Foma say Foma400 for a film closer to 100... So what's ISO? Nothing... One of a thousand posible tests in one of a thousand developers. ISO is not real... Film's not static: it's like a rubberband...
AND it requires what It requires: different amounts of exposure and development for different amounts of contrast in our scenes.
I talk about stablishing real film speed, something common ISO just don't reflect... A different thing would be if manufacturera had to say both ISO for sun and ISO for shades in D-76 for optimal G3 printing... Then I would believe in ISO. Long ago, ISO has been just marketing.
Sounds fair because of HP5's unusual design, a lot of versatility because of its mix of very different grain sizes... Possibly other film designs would behave differently...I have a bunch of times depending on SBR, but in reality, I rarely go outside of N-1/N+1. In fact, I rarely use N- times even if the scene calls for it. This is my experience with HP5 and Pyrocat-HD, anyway...
OK. I believe in ISO because it’s scientific.
The 1962 speed change is a fun story. So is flare, K, Zone System. Weston speeds and Hurter and Driffield inertia speeds.
I bought a book by Ron Callender a couple years ago, it was fun getting a post from the UK including a postcard of Ron’s personal photography... you can read his writing here... https://books.google.com/books?id=PJ8DHBay4_EC&printsec=frontcover#v=onepage&q&f=false
I am happy we moved away from “super fast”, “ultra fast” - those really we’re marketing terms.
Ah well, wait until you start rating film by the 0.3 gradient or Delta-X parameter. Then you will find the ISO was right all along. Looking just at the 0.1 speed point doesn’t always “tell the whole story”.
Now there’s a question I can answer. D-76 1:1 .....So, times for different types of light with TMY2, anyone? I like it in D-76 more than in Xtol, and in Clayton F-76 more than in Microphen in case I want Phenidone...
Thanks everyone.
Wow you do a lot.
Except for the fresh Kodak films every one has different development time to meet ASA parameters. But I always start from there.
Ah well, wait until you start rating film by the 0.3 gradient or Delta-X parameter. Then you will find the ISO was right all along. Looking just at the 0.1 speed point doesn’t always “tell the whole story”.
Am I the only one thinking VC printing alone, is inferior to VC printing + a negative with some contraction or expansion?
I have not done a specific test on It, but, do we reach identical wet prints with those two different systems?
It seems that's what some photographers are saying here...
Well, if the expansion produced by extended development is tonally identical to the contrast bump given by higher contrast filters, this can be true...
I think I was taught the best way is to adapt negative to the scene, not just paper...
Sounds fair because of HP5's unusual design, a lot of versatility because of its mix of very different grain sizes... Possibly other film designs would behave differently...
I don't think the ISO standard reflects that. It's of course an artistic choice, the legitimacy of which isn't debatable. But it's not what most people seek in b&w. If I have a negative that's exposed for the shadows, I can still chose to make a print that emphasizes mid-tones and highlights. From a negative exposed for the highlights, the shadows may be just gone. The flexible negative wins for me.I'm with Ken - the mid-tones and highlights matter most (and the ISO speed standard reflects that).
I'm with Ken - the mid-tones and highlights matter most (and the ISO speed standard reflects that).
They actually do - both directly and indirectly.I don't think the ISO standard reflects that.
I have 'taken' to the means offered by Dr Martin Scott for Kodachrome development which probably has the 'tightest' of 'control standards'. Meter (by reflection) for a 'white with texture' and 'place' that in ZVlll and 'go' for "Normal" development which then 'allows' the shadows to "fall where they may" His reasoning?....The 'viewer's' eye is usually "FIRST" drawn to the 'lighter' parts of the image for 'detail and information/'. I've been following that 'mantra' for many years and am more than 'satisfied' with the results 'I" get.
Might I suggest you try it for yourself before sending me replies (or mail) with "BULL-Sh**" as the first (or only) words
Ken
I have 'taken' to the means offered by Dr Martin Scott for Kodachrome development which probably has the 'tightest' of 'control standards'. Meter (by reflection) for a 'white with texture' and 'place' that in ZVlll and 'go' for "Normal" development which then 'allows' the shadows to "fall where they may" His reasoning?....The 'viewer's' eye is usually "FIRST" drawn to the 'lighter' parts of the image for 'detail and information/'. I've been following that 'mantra' for many years and am more than 'satisfied' with the results 'I" get.
Might I suggest you try it for yourself before sending me replies (or mail) with "BULL-Sh**" as the first (or only) words
Ken
Ah I see what you mean. Of course in comparison to a lower (ZS) speed rating, the ISO rating "favors" the highlights, so to say (although with modern films, printing them doesn't get the least bit harder with the ~2/3 stop more exposure you speak of).They actually do - both directly and indirectly.
The ISO standards were developed based on "best looking print" tests, which were heavily influenced by people's subjective response to prints. And those responses are heavily biased toward mid-tone and highlight rendition.
A straight comparison between the testing methods reveals that in many cases a Zone System film speed will be just 2/3 of a stop slower than an ISO speed. Exposing at the ISO speed favours the highlights, while exposing at the Zone System film speed favours the shadows.
It is important to remember that ISO standards were/are designed in relation to un-manipulated machine prints (think volume labs).
Other film speed standards - such as the Zone System standards - are keyed to shadow densities, with the unspoken assumption that techniques like burning and dodging will be available to the skilled darkroom worker.
But we're talking about b&w film and wet printing, yes? B&w film just goes on and on and on in the highlights, they don't go featureless, just less contrasty if the overexposure is extreme.It makes sense. Viewer usually stands better blocked shadow than textureless white areas.
The net effect of metering for the highlights is that frequently one ends up using less exposure than if one bases exposure considerations on the shadows.But I don't quite get your point, as you fell in line with KenS, who recommended metering for the highlights.
Edit: Brain fart. Not getting your point anyway. Going to bed.The net effect of metering for the highlights is that frequently one ends up using less exposure than if one bases exposure considerations on the shadows.
That is the correlation.
Well the ASA/ISO speed intends to discard a little shadow detail because it’s well understood that people don’t look at the blackest blacks for detail. Because you can afford to throw it out, you can give a stop less exposure than you would give by metering a shadow and “placing on Zone III”. MattKing is just saying incident metering (or metering a highlight and “placing on Zone VIII”) will tend to give you the lesser exposure.Edit: Brain fart. Not getting your point anyway. Going to bed.
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