Where these numbers come from is ALWAYS worth knowing and understanding but the science and maths seem to prevent from understanding.Well, it's just film speed after all. However at issue is the rule of downrating relative to ISO speed. In that context it can potentially be somewhat illuminating for one to learn a little about where the ISO standard comes from.
Specifically, and paraphrased: the rating of PanF is 50 and that renders best performance or you could rate it at half speed and accept lower performance.Ilford then goes on to talk about how the film may be exposed at EI 25-50.
I wish more people realized that. Most of his really good stuff succeeds despite “poor” negative quality for one reason or another. The other thing you find is “well controlled” negatives which nevertheless were not easy to print.
In reality, as long as exposure is sufficient to record what you need, there is not much else in the way of true control in the making of negatives that translates to high print quality. You make great prints with printing technique work. Printing (or editing in digital/hybrid) is where we have the real control.
and color theory too!
Michael_r, I would call it a suggestion that never got to 'rule' status. But what caught my attention was the idea that there was ever an actual consensus here that a lens must be a sharp as possible.
I’m a long-time fanboy... since graduate school some 40+ years ago, but don’t have an autographed picture. You are very lucky, in a nerdy sort of way!He was the chairman of the Subcommittee of Colorometry. They determined that color was psychophysical and they had something to do with the development of CIE. I was going to mention it but didn't want of come off as a fan boy. I also have a picture of him somewhere at home.
I notice that there is still a peak in quality to the right of the "first excellent print" point (i.e., more exposure). That peak of even better quality wouldn't happen to be about 2/3-stop more exposure than box speed, would it?
FWIW, for all the films I've worked with for longer periods of time and for which I've honed my personal E.I., the best results are all 1/3 - 2/3-stop slower than box speed.
Developers make a difference too...
Doremus
As quality films characteristic curve is pretty linear, why even put anything on toe. Just overexpose heavily on the straight line which continues to the moon on many films.
"How many stops is the usable range on this film?" "Yes."
I think all we usually disagree on a little when if comes to this stuff is what a well exposed and well developed negative means in terms of procedure. I started out with the relative complexity and implied control of the Zone System, but then after going down some rabbit holes, came out the other end with a simplified view of what a good negative is. For me it is just a recording when it comes to exposure, and development is basically "normal" almost all of the time, including exposures made under extreme contrast conditions.
I realized when it came to making prints, as long as the negative had enough exposure, the rest of it was largely a zero-sum game. Changing the gradient would replace one problem with another.
I also found when I did the rabbit hole tests of developers, processes etc. most of the time the assumptions people make were incorrect. In fact I would feel pretty comfortable in saying many people who think they are making finely tuned, controlled negatives are not. People who are good printers can often subconsciously work around this when they print, and then assume the negative had properties it didn't have.
On the subject of EI specifically, what I would say is that the printing is what matters, and therefore that if a great printer finds he consistently has a better time printing when he sets his exposure meter to a speed different than ISO, makes perfect sense to me. But I think that is really the only way to determine a practical EI. The rest of the EI testing is basically arbitrary, and not related with tone reproduction.
Dude... did you just look at the URL or look at the document? That is the Hartman/Ilford data sheet. Has little to do with Freestyle except they made it easily available. Not sure what that emotional over-reaction is about...Brian - I don't give a damn what Freestyle says about Pan F. As usual, Ilford itself is over-optimistic about the speed. I've gone to a lot of hard work optimizing results with this film, just like numerous others. But I'll withhold any details for the next dedicated Pan F thread. It's a somewhat peculiar film, a fact which can either work for you or against you, depending.
That’s very interesting. But how does that make the Ilford data sheet “wrong”? If I process using the recommended chemistry will PanF perform as advertised? I will be developing in DD-X 1+4. Should I use ISO 50 or use half box speed, 25?So this does seem to get the most out of Pan F, but nothing will turn it into FP4 or TMax or seemingly any other Pan film. It will always have a very limited scene contrast range, and it's own special look.
It is the result of empirical testing of a large photographic community and quite reasonable advise in MHOSo how did the '1/2 box speed' widespread belief arise, to get us back to OP question?
So, to affirm OP oriiginal hypothesis, 'everybody says...' is the origin, rather than one specific individual or photographic organizationIt is the result of empirical testing of a large photographic community and quite reasonable advise in MHO
Not a bad strategy if you don't care about grain and you don't have to worry about shutter speed/aperture to optimize depth of field vs subject movement. For any of those cases, a faster film rating helps.
Note that the whole "first excellent print" test is based on the minimum exposure needed to achieve that goal. A bit more exposure may gain even more quality (according tot he table posted by ic-racer) and even more exposure will still yield excellent prints. I overexpose 320 Tri-X by a couple stops at times to get shadows up onto the straight-lie portion of the curve and can easily make what I consider to be excellent prints from them.
Striving to hit that minimum exposure point is important with small film and with subject movement, otherwise, as bit of an exposure buffer seems a good idea to me.
Doremus
LOL... just another stereotype that is either blindly believed or true enough times that folks consider it universally true.So, to affirm OP oriiginal hypothesis, 'everybody says...' is the origin, rather than one specific individual or photographic organization
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