Acros II - What speed are you getting?

[John Wiegerink]

Thanks John but it wasn't that change I was referring to. It was the change that chuckroast was referring to when in the early 60s, I think, the new standard on which ISO is based came into being. As far as I know ISO was simply the direct successor to ASA but was a notational change and not an apparent speed increase

pentaxuser

Yes, that's what I was getting at, "the no apparent change in a base speed" of a film. HP4 was still 400, Tri-X was still 320, Plus-X was 125...................you get the drift. So why call it ISO instead of just leaving it ASA.

 

[DREW WILEY]

Chuck - you were mixing apples and oranges. Ektar is a color film meant for standardized C41 development along with predictable box speed exposure; and it is unquestionably true box speed : I've bet a small fortune on 8X10 Ektar film demonstrating that to myself, and have won print-wise, along with plenty of critical diagnostic testing. So don't accidentally confuse that scenario with the more plastic definition of film speed which comes with black and white practice, which we bend toward our own individual needs and preferences as needed. Maybe you just made a typo by inserting Ektar into a b&w film discussion; but I didn't want anyone else potentially confused by it.

As far as basing shadow values on ZIII placement, I've always found that ridiculous, except in the case of Pan F with its exaggerated S curve and very short straight line. Yeah, I know it's been taught by certain Zone Gurus, and I also know why it is counterproductive with any number of films, and exists mainly just as an insurance policy for careless metering.
There are old traditional reasons too, involving "thick" negatives - overexposed in relation to old contact printing papers and dinosaur films like Triassic X. But then, since the film is basically overexposed, when it comes to conventional silver papers, they gotta come in with that Zonie minus-whatever sledgehammer to squish the whole scale sandwich flat enough to be printable.

But I've commented on that numerous times before. One more reason one shoe does not fit all films, when it comes to factoring realistic speed. The specific nature of the characteristic curve itself is critical. They aren't all the same.

 

[chuckroast]

I wonder why films' speed were changed Was this all the manufacturers' joint decision to "improve" speed for marketing reasons or did it come from some kind of independent body who felt that their study of film speed indicated that ASA based on the current definition of how you test for film speed was a fairer representation of what the film would then produce for the average user who represents nearly all of the market

Or was the change made for none of those reasons?

Thanks

pentaxuser

Over on the pure-silver list, Richard Knoppow explained this in some detail a while back:

[pure-silver] Re: Musings On "Real ASA" And Development Methods

[pure-silver] Re: Musings On "Real ASA" And Development Methods, pure-silver at FreeLists

www.freelists.org

 

[chuckroast]

Chuck - you were mixing apples and oranges. Ektar is a color film meant for standardized C41 development along with predictable box speed exposure; and it is unquestionably true box speed : I've bet a small fortune on 8X10 Ektar film demonstrating that to myself, and have won print-wise, along with plenty of critical diagnostic testing. So don't accidentally confuse that scenario with the more plastic definition of film speed which comes with black and white practice, which we bend toward our own individual needs and preferences as needed.

Ach, I was typing faster than I was reading. My bad.

 

[pentaxuser]

Over on the pure-silver list, Richard Knoppow explained this in some detail a while back:

[pure-silver] Re: Musings On "Real ASA" And Development Methods

[pure-silver] Re: Musings On "Real ASA" And Development Methods, pure-silver at FreeLists

www.freelists.org

Thanks I have had a quick look at Richard Knoppow's explanation and have pasted some of his words here as follows:

"Up until the early 1960s,
film ASA were about half of what they are today. The philosophy was "what
is the exposure that will yield a good image?" Sometime thereafter, film
speeds magically doubled because the measurement standard was changed to
"What is the minimum exposure that will render an image on the film?" This
persisted for both ASA and DIN. It became more like a mileage estimate on a
new auto - not absolutely accurate in actual practice, but useful for
comparing one film to another - an ASA 400 film can reasonably be expected
to be 1 full stop more light sensitive than an ASA 200 film.

This - in large part - is why the "real" ASA of films turns out to be 1/2
box speed - the way ASA (and DIN) are calculated is not realistic for real
picture taking.

So it appears that a change in philosophy was the cause of the speed change which was a doubling Unfortunately he doesn't say where this change came from nor which parties such as possible the major film manufacturers were the decision makers. This would seem to matter as the change resulted in what Richard Knoppow regards as a deterioration and from my reading a serious one at that. While the minimum exposure rendering an image is a phrase that reveals little without clarification of what is an acceptable image Richard Knoppow goes on to in the last paragraph of the quote to use the phrase "not realistic for real picture taking. It isn't clear what he regards as real picture taking as he doesn't specify.

We can deduce, I think, that real picture taking is what meets his standards but he doesn't state what his standard are All we know is what they are not i.e. not the current box speeds

He goes on to say:
What all this extended low agitation gibberish does (among other things) is
so fully develop the shadows that you DO get good images at the full rated
box ASA.

He clearly is not happy with whatever extended low agitation gibberish means but seems to admit that it is a way of getting good images at full rated box speed. So I am unclear why this is gibberish Any idea what it constitutes? Is it the current Ilford/Kodak agitation regimes or something different such as a form of semi-stand? It sounds as if to get good images at what is to Richard an unrealistically high "box speed" the film makers should be advocating extended low agitation so it does suggest that Ilford/Kodak are doing this with their current regimes of at least. Here's Kodaks : "Provide initial agitation of up to 5 cycles, depending on your results. For KODAK PROFESSIONAL T-MAX Films, provide initial agitation of 5 to 7 cycles in 5 seconds. For an invertible tank, one cycle consists of rotating the tank upside down and then back to the upright position 6. After the first 30 seconds, agitate for 5 seconds at 30-second intervals. Agitation should consist of 2 to 5 cycles, depending on the contrast you need and the type of tank"

Here's Ilford's The following agitation is recommended for spiral tank processing with ILFORD chemicals. Invert the tank four times during the first 10 seconds. Repeat these four inversions during the first 10 seconds of each subsequent minute of development

This may be slightly less agitation that Kodak recommends but neither strikes me as low end agitation which Richard feels is needed.

So I am a bit puzzled here? If you know what Richard meant more specifically by extended low agitation can you let us know

What is clear is that what he needs when he takes pictures and processes the negatives is not what he believes the current box speeds as established by the current test will give him but doesn't really say what his real pictures contain that the same picture taken at box speed will not contain

Yes he is clearly raging against the "dying of the light" of film speed tampering without indicating why or to what extent the new standard of box speed allows the "dying of the light" in terms of general acceptable standards of producing negatives that gives us reasonable shadow detail

Thanks

pentaxuser

 

[MattKing]

The thing is that films used to be rated at half the ASA they are today when the goal was "expose enough to make a decent image". When that changed to "expose enough to get anything at all on the negative" ASAs magically doubled overnight. So "ISO Speed"
really isn't a good practical indicator of the exposure needed to get to reasonable shadow detail. It's just a relative measure of how one film stacks up against another. It's more of a nerdy densiometric definition of speed than it is a practical measure for the working photographer.

The 1960s change more accurately reflected then current films and other factors, including the prevalence of multi-coating.
If you use both a zone system approach and an ISO approach on the same roll, and send, for example, 100 such rolls to a commercial lab to be developed and printed, statistically speaking there will be more "good" prints coming back from the ISO exposed negatives than the Zone System exposed negatives.
ISO criteria better reflects print quality results when there are no printing adjustments (dodging, burning, differential contrast) employed.
The films that were suited to the pre-1960s ASA criteria are long gone. They were mostly long gone before the change.

 

[MattKing]

That Richard Knoppow analysis has it backwards - better prints come from properly exposed, rather than over-exposed negatives.

 

[faberryman]

Who exactly is Richard Knoppow and why should we pay attention to what he has to say?

Based on his discussion in the linked article, he doesn't sound like an expert on film speed to me.

I have the ISO standard for B&W negative still film but not for the others so can't describe the difference in detail. Unfortunately, while the standards are available from NIST they are quite expensive.

It seems to me an expert on film speed would have the standards so he could do a comparison.

The most interesting thing to me about the removal of the safety factor in 1960 is that they didn't revise Sunny 16 at the same time.

 

[chuckroast]

The 1960s change more accurately reflected then current films and other factors, including the prevalence of multi-coating.
If you use both a zone system approach and an ISO approach on the same roll, and send, for example, 100 such rolls to a commercial lab to be developed and printed, statistically speaking there will be more "good" prints coming back from the ISO exposed negatives than the Zone System exposed negatives.
ISO criteria better reflects print quality results when there are no printing adjustments (dodging, burning, differential contrast) employed.
The films that were suited to the pre-1960s ASA criteria are long gone. They were mostly long gone before the change.

I am unclear on how you come to this conclusions. Film ASAs literally doubled overnight when this change was implemented, without a single emulsion change.

Commercial labs of that era often employed overnight semistand development in something like D-23. This meant that the film hit full box ASA and the highlights got reined in. But if you're developing using the recommended twice-a-minute agitation as recommended for daylight tanks - i.e., something in the neighborhood of 5-15 minutes, depending on the developer - you are not going to hit full box ASA (unless your meter, shutter, or thermometer are out to lunch, then it can appear that you have done so).

Zone system assumes two things: You have properly calibrated your own effective ASA for each film/dev combo and that you've adjusted the development time to match the gamma you need for your paper, your light source, your printing style and so on. So, no, a commercial lab isn't going to match that and it would be silly to expect it to.

I see a lot of stuff on the internet and in real life that show thin, detail impaired negatives because people are shooting at box speed.

But don't take my word for it. Take your favorite film. Expose it a 1/2 box speed, set the exposure by metering the shadows and then stopping down 2 stops. Develop 20% less than indicated by the manufacturer. Go look at the strength of those negatives. (This does not account for huge SBRs and having to manage highlight - that's a discussion for another day.)

Keep in mind that this is an approximate rulle-of-thumb that does have to be tuned for each person's tooling and workflow, but across literally dozens of film/dev combos, I found it to be very close. So much so, that I no longer do denisometric tests I just use the aforementioned rule to get started and then tune by eye thereafter. Well, I used to do that. Increasingly, I find myself exposing film at box speed, and semistand processing it in a highly dilute formulation of a compensating developer like D-23 or Pyrocat-HD. for 60 minutes. This gives me full shadow speed, well managed highlights, and expanded midtone contrast.


BTW, you can see this in the OP's original images posted here. A significant lack of shadow detail often running to pure black.

 

[MattKing]

I am unclear on how you come to this conclusions. Film ASAs literally doubled overnight when this change was implemented, without a single emulsion change.

Prior to then, the old ASA criteria had become more and more inappropriate, as the materials and equipment - including photofinishing materials and equipment - evolved. The change was implemented to deal with that, among other things. And vastly more film has been exposed in the last 60 years than in the times before then.

Zone system assumes two things: You have properly calibrated your own effective ASA for each film/dev combo and that you've adjusted the development time to match the gamma you need for your paper, your light source, your printing style and so on. So, no, a commercial lab isn't going to match that and it would be silly to expect it to.

However, commercial labs still handle far more film than all the Zone System users in the world combined - even in these modern times.

If you are getting good results using a particular method - continue with that.

Most people are not printing in the darkroom, not using fixed contrast paper if they do, and are using roll/135 film to photograph a variety of subjects, under a variety of light conditions on each roll. The zone system approach is not well suited to their needs, and if they try to apply some of its approaches to their usage, it will be a poor fit.

You can cherry pick some of the zone system's points though - particularly the ones related to visualization. However, the Zone System point which emphasizes shadow detail at the expense of excess mid-tone and highlight exposure and resulting poorer mid-tone and highlight rendition - which is what using a Zone System approach to film speed will do for you, unless you compensate under the enlarger - will result for most people in inferior prints and scans.

 

[MattKing]

The most interesting thing to me about the removal of the safety factor in 1960 is that they didn't revise Sunny 16 at the same time.

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.

 

[DREW WILEY]

Black and white films simply aren't all the same, even if they were all hypothetically speed-matched. Even back in the 60's, any serious student aspiring to go pro had to know the practical distinction between long-toe Plus X pan, nearly straight line Super XX, and medium toe Tri-X. That could make or break your career.

With a precise meter reading, you could place deep shadow values for Super XX way down on Zone 1 if you wanted to, and get decent gradation the whole distance. Try that with Plus-X, and it would be a bellyflop, since that, with its long upswept curve, was marketed with studio applications in mind, catering to high-key Caucasian portraiture in white wedding dresses etc. Today's film distinctions can be just as dramatic.

Therefore, to be realistic, the Zone System shouldn't be thought of in segments with hard boundaries, but more like a rubber band which can be stretched or re-contracted as needed. Zone dogma can be boiled down to a shorthand method for assigning film exposures discrete development categories, along with the basic advice, "expose for the shadows, develop for the highlights".

 

[chuckroast]

Prior to then, the old ASA criteria had become more and more inappropriate, as the materials and equipment - including photofinishing materials and equipment - evolved. The change was implemented to deal with that, among other things. And vastly more film has been exposed in the last 60 years than in the times before then.

However, commercial labs still handle far more film than all the Zone System users in the world combined - even in these modern times.

But that's not the benchmark. Commercial labs - to the extent that they even exist -are largely producing dreadful results.
The point of ZS or any other exposure discipline isn't to be less bad than the mass produced outcomes, but
to actually strive to be good.

If you are getting good results using a particular method - continue with that.

Most people are not printing in the darkroom, not using fixed contrast paper if they do, and are using roll/135 film to photograph a variety of subjects, under a variety of light conditions on each roll. The zone system approach is not well suited to their needs, and if they try to apply some of its approaches to their usage, it will be a poor fit.

I routinely use ZS to manage exposure. Combined with split grade printing and semistand/EMA development, I do not
encounter the maladies you list. Yes, ZS taken literally as it was handed down by Minor and Adams a half century ago
can be limiting, but pretty much no one - other than beginners, perhaps - reads ZS as some kind of immutable holy writ.

I do this, by the way, with both sheet and rollfilms. I "get away with it" because ZS gives me good shadows and semistand/EMA protects the highlight and expands the midtone local contrast. VC split printing lets me control contrast locally in very useful ways.

You can cherry pick some of the zone system's points though - particularly the ones related to visualization. However, the Zone System point which emphasizes shadow detail at the expense of excess mid-tone and highlight exposure and resulting poorer mid-tone and highlight rendition - which is what using a Zone System approach to film speed will do for you, unless you compensate under the enlarger - will result for most people in inferior prints and scans.

This is only the practice of early ZS users. Today we have a body of practice that goes well beyond that.

 

[chuckroast]

Black and white films simply aren't all the same, even if they were all hypothetically speed-matched. Even back in the 60's, any serious student aspiring to go pro had to know the practical distinction between long-toe Plus X pan, nearly straight line Super XX, and medium toe Tri-X. That could make or break your career.

With a precise meter reading, you could place deep shadow values for Super XX way down on Zone 1 if you wanted to, and get decent gradation the whole distance. Try that with Plus-X, and it would be a bellyflop, since that, with its long upswept curve, was marketed with studio applications in mind, catering to high-key Caucasian portraiture in white wedding dresses etc. Today's film distinctions can be just as dramatic.

Therefore, to be realistic, the Zone System shouldn't be thought of in segments with hard boundaries, but more like a rubber band which can be stretched or re-contracted as needed. Zone dogma can be boiled down to a shorthand method for assigning film exposures discrete development categories, along with the basic advice, "expose for the shadows, develop for the highlights".

That's why ZS exposure control demands that you test for each different film/development combo - because films are not the same.

Let me repeat: The 1/2 box speed, -20% development rule-of-thumb is a starting point that gets you in the ballpark, it is not the final answer and I've never thought it was. It's designed to get you in the ballpark without having to spend hours doing densitometry (which is super boring). From there we tune by eye.

But I have mostly given up on conventional development - at least for outdoor SBRs - favoring instead the protections offered by high-dilution, low agitation, long development time techniques. Combined with ZS exposure placement discipline, it yields very rich negatives that lend themselves to making expressive prints. But semistand and EMA are tricky to get right (I know, I spend a year doing it) and most people don't have the patience.

 

[chuckroast]

Who exactly is Richard Knoppow and why should we pay attention to what he has to say?

Based on his discussion in the linked article, he doesn't sound like an expert on film speed to me.



It seems to me an expert on film speed would have the standards so he could do a comparison.

The most interesting thing to me about the removal of the safety factor in 1960 is that they didn't revise Sunny 16 at the same time.

Who is faberryman and why should we pay attention to what he has to say?

Something isn't right or wrong because of who says it. Demanding proof by authority is an academic's stance and does not propel the discussion forward.

 

[DREW WILEY]

Well, I had plenty of patience for serious densitometry, curve plotting, and so forth, and regard it as a very helpful background at least. But super-long development sessions, nope - I'm not a candidate for that. I don't want to be either standing or semi-standing on my deformed flat feet that long. But it is interesting to read about.

 

[chuckroast]

Well, I had plenty of patience for serious densitometry, curve plotting, and so forth, and regard it as a very helpful background at least. But super-long development sessions, nope - I'm not a candidate for that. I don't want to be either standing or semi-standing on my deformed flat feet that long. But it is interesting to read about.

You don't have to - or at least, I don't have to. My process is simple:

1. Turn out the lights in the room adjoining the darkroom
2. Start the semistand process
3. Loosely cover the tank with a dark plastic container - like the kind food is delivered in
4. Step back out into the adjacent room
5. Close the darkroom door and turn on a light
6. Repeat as needed

I spend my hour long development sessions mostly outside the darkroom doing other things. It's actually way more productive than banging away at an inversion tank for 10 minutes.

I agree that some background in curve plotting with a densitometer is useful. It's just doesn't need to be done endlessly.

 

[Steven Lee]

So why call it ISO instead of just leaving it ASA.

Here's my understanding of what happened: ISO stands for international standards organization. The mission of this organization is obvious: to have an agreed on global standards. ISO has been growing over the years, adding more applications. Prior to mid 80s film speed was not standardized. When I grew up I remember seeing ASA (American), DIN (German?) and GOST (Soviet?) speed ratings printed on film boxes. In mid-80s ISO finally got around to standartizing the film speed, and they simply picked the American standard (ASA) and renamed it. Happy to be corrected, but that's how I remember it.

 

[chuckroast]

Here's my understanding of what happened: ISO stands for international standards organization. The mission of this organization is obvious: to have an agreed on global standards. ISO has been growing over the years, adding more applications. Prior to mid 80s film speed was not standardized. When I grew up I remember seeing ASA (American), DIN (German?) and GOST (Soviet?) speed ratings printed on film boxes. In mid-80s ISO finally got around to standartizing the film speed, and they simply picked the American standard (ASA) and renamed it. Happy to be corrected, but that's how I remember it.

I believe that is roughly correct. Having served on a number of international standards bodies over the years, I can report with firm conviction that nothing is more political or more useless than people sitting around setting standards. If it's an international standards body, it's 100X worse because the people in question both want to flog their individual agendas as well as indulge their nationalist and cultural instincts. (The one exception is when a standard is codifying existing practice.)

Oh well, I got some nice all expense paid first class trips to Europe that way ')

 

[DREW WILEY]

Oh great, you just made it harder, Chuck! I do have a set of double doors if I need to exit the sink room in full darkness. But then what? Go to the woodshop and get dusty, or sit out on the porch reading while the cat jumps on me and gets me covered with cats hair, which in turn gets into the darkroom? Or else my wife spots me outside the darkroom, and assumes I'm available for chores, and the whole film session goes to ruin with three hours worth of overdevelopment.
Think I'll stick with standard PMK etc.

 

[Steven Lee]

If you use both a zone system approach and an ISO approach on the same roll

What ZS approach are you referring to? I see a lot of inconsistency in how zone people reason about exposure and film speed. Is there the One True Zone System method of measuring film speed, which is not subjective, i.e. excludes photographers personal preferences and vague criteria such as faint signs of tonality?

 

[chuckroast]

Oh great, you just made it harder, Chuck! I do have a set of double doors if I need to exit the sink room in full darkness. But then what? Go to the woodshop and get dusty, or sit out on the porch reading while the cat jumps on me and gets me covered with cats hair, which in turn gets into the darkroom. Or else my wife spots me outside the darkroom, and assumes I'm available for chores, and the whole film session goes to ruin with three hours worth of overdevelopment.

Hahaha - happy to help. My cat also fancies himself as my assistant though he knows he is not allowed in the darkroom ever - which reeeeeeaaaly annoys him. But film in solution doesn't really have issues with a little cat hair, does it?

Seriously, try it some time. It's borderline amazing what is possible. Note that I silver print and use split VC techniques under a diffusion VC head, so I have many knobs to turn when making prints...

BTW, you'll find my notes on this stuff here:

https://gitbucket.tundraware.com/tundra/Stand-Development

 

[faberryman]

Who is faberryman and why should we pay attention to what he has to say?

I certainly hope nobody is quoting anything I have to say as authoritative.

Something isn't right or wrong because of who says it. Demanding proof by authority is an academic's stance and does not propel the discussion forward.

He is being held out as reciting factual information on the development of film speed standards. He admits he doesn't even have the film speed standards, so I am not inclined to give what he says much credibility except in the most general sense. It sounds like regurgitated internet scuttlebutt to me. We all know the safety factor was eliminated in 1960 and as a result ASA speeds doubled. Certainly no new insights. You may feel differently.

 

[chuckroast]

What ZS approach are you referring to? I see a lot of inconsistency in how zone people reason about exposure and film speed. Is there the One True Zone System method of measuring film speed, which is not subjective, i.e. excludes photographers personal preferences and vague criteria such as faint signs of tonality?

The ur definition of it was to pick a speed that gave you 0.1DU above FB+F in Zone I - i.e. to get the beginnings of shadow detail out of the left hand side of the HD curve.

Zone System stresses finding YOUR personal ASA - the speed that gives you the negative that works well with the way you meter, you develop, you agitate, you print (or scan) and so on. It's not supposed to be an international standard, it's supposed to be YOUR standard. That's why there is lots of variability.

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.

 

[chuckroast]

I certainly hope nobody is quoting anything I have to say as authoritative.



He is being held out as reciting factual information on the development of film speed standards. He admits he doesn't even have the film speed standards, so I am not inclined to give what he says much credibility except in the most general sense. It sounds like regurgitated internet scuttlebutt to me. You may feel differently.

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.