Need help using zone system with film with 19-stop dynamic range

Stephen Benskin said:

So basically a virtually meaningless statement. Sure maybe you were generalizing or using imprecise language. I have no problem with that, but then there shouldn't be claims about precision and disparaging others for their lack of it.

Let me be more precise on flare. Veiling flare is an overall non-imaging forming exposure that compresses the shadows and comes primarily from the luminance of the scene interacting with the optical system of the camera. The average flare for a statistically average scene is around one stop. It can be higher or lower. A stop flare adds a stop exposure to the shadows, changing the placement of the shadow exposure and disproportionately compressing the shadow values. It effectively takes a 7 stop scene and reduces it to a 6 stop illuminance range at the film plane. This is a part of defining "Normal" development.

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I did a flare test where a "black box" target was created. A hole was cut into a black velvet lined box. A hood surrounded the opening to reduce extraneous light from entering. Cards of single tones and mixed tones were used to surround the opening and introduce flare. It was shot on 35mm film. An exposure was determined. After the test a sensitometric exposure was place at the end of the roll. The resulting values from the test are placed onto the film curve.

Now, this just shows the change in shadow placement caused by flare and not the compression.

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Thanks for sharing! This is much deeper than I ever go into the technical side but it’s fun to read about it.

DREW WILEY said:

It takes an entire stop more of exposure to essentially launch Delta 100 off the toe onto the straighter line portion of the curve. Therefore, for all practical purposes, I consider it an ASA 50 film. But most Ilford films are overoptimistic about their rated speed.

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Interesting. I do not understand all the discussion about the toe versus the straight line part of the curve. But exposing Delta 100 at 50: reduce development? Won't this be a dense negative otherwise?

Bill Burk said:

Because of the nature of Zone System metering, when you test you will find the speed 2/3 stop (2 ASA marks) lower than rated box speed.

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OK, I see by now this humble thread has gone into (what appears to me) massively arcane sidebars... I would like to bring it back to the first page of feedback I received:

People suggested that with the zone system I give it an extra 2/3 stop. What about when I use matrix metering from my Nikon D610 to get an exposure reading; would that still need to be compensated by 2/3 of a stop?

You either make the adjustment with the speed setting, changing your EI, or in the shooting, by opening up. May I also suggesting understanding the reason for any adjustment and not just accepting it as a rule of thumb.

Stephen Benskin said:

You either make the adjustment with the speed setting, changing your EI, or in the shooting, by opening up. May I also suggesting understanding the reason for any adjustment and not just accepting it as a rule of thumb.

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Thanks, but not too sure your answer clarifies for me if I should still be doing it when matrix metering or not? It seems more to address how to do it, which I have no problem with.
As for the recommendation that I understand the reasons why, I see this as a first step towards some form of comprehension: getting to know the exceptions.

The idea is really about the EI of the film, so it's about the overall placement of the exposure. The best way is to change the speed rating on the camera and meter your usual way. Conceptually it's no different than shooting with film with a slower film speed (In reality, it's rather more involved). The ISO is 100, you think EI 64. Set the camera at 64.

I do this with trepidation, but I think what Stephen is saying is:
"If you like the results you get with the meter set at an EI of 64, you should set the meter to an EI of 64."
The meters are set up to give results that look a certain way. You need to either accept that, or make a choice that is more to your liking.
The Zone system is about visualizing a result. You need to choose a setting on your matrix metering camera that gives you the result that you visualize. Zone system photographers tend to visualize results in a particular, around 2/3 of a stop more exposure way.
They also tend to have beards and wear wide brimmed hats, but that is the subject for a different thread.

Matt, there are no thumbs up icons, but "thumbs up!" anyway.

Thanks Stephen for reminding me of something I've known for the past forty years. Doesn't change an iota of what I've been stating. But it's probably useful info for others. Flare can be tested for, factored, and yes, largely eliminated (and yes, I know you're factoring the optical train too; but I don't want to turn this into a lens design thread). But flare is neither friend or enemy; it all depends. I sometimes deliberately allow it affect a select portion of the image, turn it into an esthetic tool. It's part of the magic of those old blue-sensitive shots by people like O'Sullvian and Muybridge. But a good magician never shows his hands. There are no hard rules, even for me personally. I approach each shot and its potential print on its own basis.

Matt - you are aware of "personal ASA" in relation to all of this back and forth chatter? Pre-visualization is far too an elastic or vacuous concept for this thread. No doubt there are all kinds of previous debates about it on the Forum in general. Minor White almost made a kooky religion out of it.

Peter - matrix metering is like shooting a shotgun at a scattered flock of geese, and hoping you get statistically lucky. Depends on who programmed the slot machine. There's nothing precise about that. If that's what you have in mind, ignore most of this thread. It won't make sense. I'm talking about comparing critical points in the film curve, which means having the ability to measure discrete spots in the scene itself. That's true of the Zone System as well, which you apparently are unfamiliar with. There is nothing "arcane" about any of this. That doesn't mean you need to apply any of it if you are already happy with your results. But better knowing the characteristics as well as limitations of films in a very specific manner has indeed helped many of us. Scientifically, film sensitometry, plotted as logarithmic "characteristic curves" is the common denominator standard behind everything. The Zone System is a popular teaching model for how to get predictable results exposing and developing film, based upon a simplification of sensitometry itself into discrete pigeonholed "zones", which is a good starting point, but certainly doesn't solve everything. If all this confuses you, just do what Stephen suggested, which is like trying improve your odds on the slot machine inside your camera.

Kodachromeguy - go to a used bookstore and find an old Kodak black and white film data guide. Somewhere in the earlier pages there will be a succinct explanation of how film curves are plotted toe onto straight line onto shoulder, and what that means, and how films differ in that respect. A lot of people also get help out of Ansel Adams' old book, The Negative. Other sections of that same book outline the basics of the Zone System. Much more involved texts are available, but I recommend something simple to start out. Just be aware that some of us on this particular thread are speaking about alternate methods due to a perceived weakness in the Zone System. But don't let that deter you or confuse you. Start with the basics first.

peterB1966 said:

OK, I see by now this humble thread has gone into (what appears to me) massively arcane sidebars... I would like to bring it back to the first page of feedback I received:

People suggested that with the zone system I give it an extra 2/3 stop. What about when I use matrix metering from my Nikon D610 to get an exposure reading; would that still need to be compensated by 2/3 of a stop?

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Don’t in this case. When you use matrix metering the correct film exposure will occur at the rated speed.

When you do Zone System testing you will think the film is 2/3 stop slower than rated speed. And when you do Zone System metering with the 2/3 stop slower rating, you will get readings for the correct film exposure.

But...
You may still elect to use 2/3 stop compensation with matrix metering, for a different purpose - a reason many people give - they like getting more detail in shadows.

It is a great plan to meter two different ways as you size up a scene. If the readings are identical you can be certain you did something right. If the readings differ, you can think through what is happening. In most cases both are correct!

In some cases matrix metering might evaluate a scene and determine exposure favoring the highlights, that may be a circumstance when Zone System metering and placing the shadows would give different correct exposure than the matrix metering. You could Zone System meter and place a higher value to see if that explains the difference.

And my stories describe practices that lead to varying results anyway.

DREW WILEY said:

Thanks Stephen for reminding me of something I've known for the past forty years. Doesn't change an iota of what I've been stating. But it's probably useful info for others. Flare can be tested for, factored, and yes, largely eliminated (and yes, I know you're factoring the optical train too; but I don't want to turn this into a lens design thread). But flare is neither friend or enemy; it all depends. I sometimes deliberately allow it affect a select portion of the image, turn it into an esthetic tool. It's part of the magic of those old blue-sensitive shots by people like O'Sullvian and Muybridge. But a good magician never shows his hands. There are no hard rules, even for me personally. I approach each shot and its potential print on its own basis.

Matt - you are aware of "personal ASA" in relation to all of this back and forth chatter?

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It was hard to tell what you do and don't know based on your fact free and evasive responses. However, with my responses, I want to be inclusive with those who may not be aware of all of the details of the discussion.

Drew, you are aware that ASA is an outdated term, but apart from that, the use of ASA or ISO implies adherence to the conditions of the standard. Any derivation from the standard uses the term EI. Technically, there can't be a personal ASA or personal ISO.

Finally, what's with all the strawman arguments?

2/3 stop...never heard that, but then I never did any testing for the Zone System other than expose film and develop it...then learn which negatives printed the best for the process. Learn from the failures, repeat the successes. Meters drift, film ages, shutters get cranky...2/3 stop is ehhh...it's all on the negative.

One factor alone accounts for 2/3 stop.

Lore tells the newcomer to Zone System testing to expect to find their findings to be half the film’s rated speed.

It’s not hard to find factors that could add up to another third stop

peterB1966 said:

Thanks, but not too sure your answer clarifies for me if I should still be doing it when matrix metering or not? It seems more to address how to do it, which I have no problem with.
As for the recommendation that I understand the reasons why, I see this as a first step towards some form of comprehension: getting to know the exceptions.

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As I mentioned earlier, you may like the results you get with 2/3 stop compensation with matrix metering.

I think a lot of people do the Zone System tests, conclude the “real” speed of the film is half the rated speed, use that going forward and love their results.

I am guilty of confusing the idea of compensating 2/3 stop more exposure... “to get more shadow detail” and “if you want to use Zone System without doing the tests”. They’re two different reasons for making the same adjustment in the same direction.




If you mix and match author’s advice, just check that you aren’t correcting for the same thing twice.

When...back in 1980? I use to 'cut my ASA in half' in the late 70s, but that was from judging the results (I'd take one 4x5 at the meter reading, and one at one more stop of light). Eventually I learned about something called reciprocity failure which was really the reason I was 'halving the ASA' (but I always set the meter at box speed, I just gave the film another stop). Early 80s I had enough money to buy a copy of The Negative and went over it and tried several things, checking out the possibilities, such as two-bath development and such.

Haa Vaughn, if it was always you I have been quoting all along, it would be funny.

Bill Burk said:

Don’t in this case. When you use matrix metering the correct film exposure will occur at the rated speed. etc

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Just want to say thank you for sticking with my daft questions during this thread, and being so humble about it. Much appreciated.

Stephen Benskin said:

The idea is really about the EI of the film ... The ISO is 100, you think EI 64. Set the camera at 64.

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OK, so after your comment I had to look up the EI, and one thing that came out is that it doesn't just determine your overall compensation, but also what you will process it at. I.e. if you shot ISO 400 at 250, then you process it at 250.

However, I was under the impression when people told be to give it 2.3 stop more that I should still process at the correct ISO, i.e. I shoot IOS 400 at 250 but then process at 400. Please confirm which would be the correct decision?

Stephen - nothing I said was evasive in any manner whatsoever. I get the distinct impression you simply don't understand what I'm stating. That's OK. How you explain and do things might work perfectly well for your own workflow; it wouldn't work for mine. It's too generic. As far as "outdated terms" go, that's what people are likely to find in outdated literature - just trying to make it easy.

peterB1966 said:

Just want to say thank you for sticking with my daft questions during this thread, and being so humble about it. Much appreciated.



OK, so after your comment I had to look up the EI, and one thing that came out is that it doesn't just determine your overall compensation, but also what you will process it at. I.e. if you shot ISO 400 at 250, then you process it at 250.

However, I was under the impression when people told be to give it 2.3 stop more that I should still process at the correct ISO, i.e. I shoot IOS 400 at 250 but then process at 400. Please confirm which would be the correct decision?

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Peter, this is a lot more involved question than you may be aware of. First, don't confuse rating the film with development. So, the simple answer is no you don't adjust development for a ISO 400 film shot at 250. I'm at work at the moment, but will address it in more detail later today.

If you are wondering about the Zone System practice of rating the film 1/2 to 1 stop slower than the ISO rating, that is mostly about different testing methodologies. Consider taking reading of the temperature outside. You would get different results if you held the thermometer in direct sun or in the shade, In order to compare apples to apples and to communicate in such a way as to have others reproduce your results, they need to know how the test was conducted.

When the ISO prefix is added to the speed rating, it means that the instructions in the ISO speed standard were adhered to. It's basically a short hand.. ASA, DIN, GOST, Schneider, and Inertia are all different ways to determine film speed. Another example is with film gradient. There are a number of different ways to determine the slope of a film curve and each approach will yield slightly different results. When CI is added to the gradient value, it means the instructions for Contrast Index were used. When Average gradient, G bar, or Gamma is used, it means one of these different methods were used.

The Zone System assumes the point to determine the speed of the film falls four stop below the metered exposure. ISO calculates it at 3 1/3. The difference is 2/3 stop,. If you weren't aware of this distinction, like pretty much everyone for 50 years, you'd think one or the other approach is wrong.. Zone System users had created many conspiracy theories over the years to explain the discrepancy.

The other way to look exposing at a speed lower than the rated speed it is that film speed is just a way to determine how to obtain an exposure that will yield quality prints under the greatest number of situations. It isn't just about the properties of the film. Film speed is psychophysical, not physical. Personally taste and metering technique also factors into how you may wish to personally rate the film.

Stephen

DREW WILEY said:

Stephen - nothing I said was evasive in any manner whatsoever. I get the distinct impression you simply don't understand what I'm stating. That's OK. How you explain and do things might work perfectly well for your own workflow; it wouldn't work for mine. It's too generic. As far as "outdated terms" go, that's what people are likely to find in outdated literature - just trying to make it easy.

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You know nothing about my workflow, my approach, or my techniques. Stop creating strawmen. "Personal ASA" was not just an outdated term. That's another strawman. The term was wrongly used. You can't have a personal ASA or ISO. It's called EI. Trust me, the study of tone reproduction theory has given me a rather good BS meter.

Phil Davis once told me about a book he was asked by a publisher to review. The author had moved and set-up a new darkroom, but he wasn't able to develop his film like he was used to. After checking everything possible, he concluded his new table was 6 inches higher than the old table. Problem solved.

I don't use personal ASA, ISO, EI, Zone System, or Beyond Zone System. All of that is too crude for my own purposes. I'm visualizing the specific shape and placement of the curve itself every shot, tailored, even though now it's almost entirely intuitive and instant due to sheer familiarity. Has it made a real difference right into the look of the prints themselves? Absolutely. Just yesterday I was in an intense forest fire burn zone - the most dramatic fire in the world last year. Talk about lighting extremes! It was a rush trip so I just grabbed the bag and tripod. Had only 4 frames of TMX left in the 6X9, plus an unopened roll of Acros. Merely adjusting the rating of the ACROS down to 50 won't make it equal to TMY @ 100. Different animals.I wasn't dealing with just shades of gray, but black upon black upon black, juxtaposed to shimmering highlights. I knew exactly what to do when I switched rolls.
I have a pretty darn good BS meter too, Stephen, and have no interest in jousting with your own ridiculous assumptions about me. Got better things to do than to play ego games. My own methodology might or might not help others. It's there if someone happens to need another option more precise than the usual suspects. But don't attack something you obviously don't understand yet, and apparently don't want to. Welcome to my ignore list.

That burnt bark is deceptively reflective. I was contrasting a burnt snag against granite, both sun-lit. It was okay, but I noticed the snag would soon be in shadow,but the granite remaining in the sun...perfect! That reduced the over-all brillence of the burnt wood, but kept it visually alive and rich in tone. I have negs and prints both ways, but only show the below. There's a couple of dots on El Cap...climbers...I noticed them when comparing the two negatives (5x7 carbon print).

I have a 16x20 print on the wall behind me I took after the fire that went through Foresta...taken above Foresta and Hwy 120. A very dark chunk of granite (its covering of moss/lichens burnt), but with brilliant white patches where the heat caused the surface layer of granite to flake off. A silver column that was a cedar, 100% ground cover gone, and more silver and black trunks in the background. Nice light...

peterB1966 said:

Just want to say thank you for sticking with my daft questions during this thread, and being so humble about it. Much appreciated.



OK, so after your comment I had to look up the EI, and one thing that came out is that it doesn't just determine your overall compensation, but also what you will process it at. I.e. if you shot ISO 400 at 250, then you process it at 250.

However, I was under the impression when people told be to give it 2.3 stop more that I should still process at the correct ISO, i.e. I shoot IOS 400 at 250 but then process at 400. Please confirm which would be the correct decision?

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My advice is... Process at 400 when shooting at 250 to get better shadow detail. That way you do not change contrast in the negative. You just give everything an equal lift.

It would be OK if you do change development because when you give greater exposure you have less risk of losing detail (with less development). To rephrase... developing less will reduce the negative contrast but maybe you can live with that.

I just developed a few rolls of double-x and was disappointed that my contrast is lower than I planned. I planned to print on a Grade 2 paper that I just got. I might have to print on Grade 3 or 4. These days that’s a non-issue for practically everyone.

But I really wanted to print these pictures on that paper and now I can’t.

I’ll cope, it’s just one of those little annoyances that bug me when things go wrong.

There is so much tolerance in black and white negative developing and printing that you can get great results while making great mistakes.

Then again you can learn to see in a way that makes you demand some particular result. You could become so particular that you are disappointed in anything but perfection.

Vaughn - wish I had more time up in the hills. I had an appointment down in the SJ Valley the next day. Yes, right on the same snags an amazing range of blacks, plus even deeper cracks, shimmering reflections, iridescence, bright specular highlights. That's what I love about it. But brilliant creek reflections and open sky in some of the same shots too. TMax territory. I reserved the Acros film for twilight and dawn, when the total contrast range was a little less extreme.

Even if it was only briefly, I needed to spend a night listening just to frogs, and awake to all kinds of bird sounds, and no barking dogs, boom boxes, or nagging house cats. It's amazing how much life gravitates towards a recent burn. But from a distance, across the canyon, you'd think the whole world had been destroyed. In all my life, I've never seen such dramatic fire impact, though in this case, I perfectly predicted it. Dead pines as far as the eye could see. But with all those pines now gone, it is also easy to survey from the ridge above what is left of homes back in there - darn few. Only two survived along the paved road atop the ridge itself.

And I love the way you composed that snag in relation to the bright granite cliff behind. Maybe someday I be fortunate enough to see the real print.