Zone System - Find EI and dev time without resorting to sensitometry

RobC · Aug 13, 2015

dichroic fog is always there in varying amounts depending on film, developer, stop and fix used. It just prints through. The less there is the better but you're unlikely to get rid of it completely with standard films and B+W chemicals. It varies between approx 1/3 to 1 stop of density.

Bob Carnie · Aug 13, 2015

In college we were pounded with , keeping the base density plus fog as low as possible for great prints.
I never could completely understand the Zone System , back then, doubt if I can discuss it properly now.

so I am probably talking about exposure fog and development fog.
Rodinal in my shop produces a higher base density plus fog than lets say D76 , but I have never found an issue with this.
the density on PMK negatives is once again very high, and like Rob says I just print through this base.

So I am wondering how people react to heavy density on the rebate.

Also we make Fuji and Kodak metallic prints . the rebate or so called white area is actually a grey, but when matted our eyes funny enough produce a white within the scene.

Michael R 1974 said:
Not sure what you mean. Are you talking about development fog (ie all developers will produce some amount of fog density), or non-image exposure/flare/flashing/pre-exposure?

Xmas · Aug 13, 2015

Michael R 1974 said:
Xmas:

All I'm saying is that virtually every Zone System-type method will result in an EI somewhere around 1/2 to 1 stop slower than ISO, so there is little need for any testing on that front. You can just downrate by 1 stop, and fine tune based on print results.

What I've been trying to get across is the difference between understanding and not understanding Zone System EIs vs ISO. If you understand the difference, you know that Zone System EIs are predictably different than ISO speeds for known reasons. If you don't understand the difference, you think ISO is a nebulous consipracy, and that the Zone System EI test is going to reveal something.

Hi Michael

I was trying to agree with you & my 4/3 adjustment is tested long term on my normal shots...
It works not going to worry about 1/2 stop.

Noel

pdeeh · Aug 13, 2015

Xmas said:
HiRon

So what were we doing before 1961 and the ASA changes?

Noel

I don't think PE was posting on APUG in 1961

Ian Grant · Aug 13, 2015

We must not forget that Kodak had the ASA part of the ISO film speed standard changed for Tmax films, they would not pass the old standard testing regime as 100 & 200 ASA. The ISO standard uses either the ASA or DIN testing.

This was why there was a full stop difference between most peoples Zone System tests and Kodak's published ISO, and why Kodak themselves recommended using Tmax100 at 50 EI for the best tonal range, that's a a FULL STOP ont a half or a third. I still have the Kodak data-sheet in my darkroom.

Ian

Xmas · Aug 13, 2015

Bob Carnie said:
So where are we all on base plus fog... does a print suffer from having a higher base density?

Not detectable in a blind test with the difference on a Avery label unless you turn over the print and look at the Avery label.

If you make a stop error in the other direction it is more obvious...

RobC · Aug 13, 2015

Bob Carnie said:
so I am probably talking about exposure fog and development fog.

fb+fog is all development and not exposure fog. So its the film rebate which is where you can measure it if you need to. It will be there even if you haven't exposed the film.

I guess it must degrade the Image Quality a tad.

I used to regularly get on about 1/3 stop of it but at some point when films and devs changed it went up to 1 stop for me and that annoys me becasue I think its excessive.

I would need to experiment with film/chemical combos to see if it could be got down to a lower level.

Xmas · Aug 13, 2015

pdeeh said:
I don't think PE was posting on APUG in 1961

Correct but I was exposing HP3 at 200 ASA.

Xmas · Aug 13, 2015

Michael R 1974 said:
Depending on the formulation of the developer and degree of development, yes base fog can vary. With most general purpose developers base fog usually isn't a material issue, even though it can vary a little. With more special-purpose formulations, sometimes fog is considerably higher (a tradeoff for other optimizations). Most staining developers will tend to produce higher base fog (higher silver fog combined with non-image stain) something like XTOL.

Normally these differences won't matter much if at all other than changing printing times a little. Technically speaking, assuming chemical fog does not interfere with low image exposure densities, and all other things being equal, lower fog is good because any fog density as added to image density, and the more density you have, the higher the graininess. But usually the differences in fog levels are too small to worry about from that perspective (barring extreme cases).

I accept more grain from increased density but I like grain.

Photo Engineer · Aug 13, 2015

Xmas said:
HiRon

So what were we doing before 1961 and the ASA changes?

Noel

I used box speed for all films until the change. That caused problems because they had a division at the Cape that tested all ISO/ASA ratings (to no avail). The ratings on the box were always on or conservative from all manufacturers. This included Kodak, Ansco, Dupont and a few others.

PE

Photo Engineer · Aug 13, 2015

Bob Carnie said:
So where are we all on base plus fog... does a print suffer from having a higher base density?

You lose effective toe speed and contrast as fog goes up. Mid and upper scale often stays the same.

PE

Photo Engineer · Aug 13, 2015

And, dichroic fog is not an issue. You cannot pick up a random piece of processed film and see dichroic fog if you use Kodak, Fuji or Ilford films.

PE

Stephen Benskin · Aug 13, 2015

Ian Grant said:
We must not forget that Kodak had the ASA part of the ISO film speed standard changed for Tmax films, they would not pass the old standard testing regime as 100 & 200 ASA. The ISO standard uses either the ASA or DIN testing.

This was why there was a full stop difference between most peoples Zone System tests and Kodak's published ISO, and why Kodak themselves recommended using Tmax100 at 50 EI for the best tonal range, that's a a FULL STOP ont a half or a third. I still have the Kodak data-sheet in my darkroom.

Ian

The introduction of the T-Max films did instigate a few adjustments to the standard. I wrote an article on this for PHOTO Techniques. The T-Max films didn't respond well to the standard's developer. So a decision was made to change the developer to more accurately reflect real world use. Hold time and method of development was changed too. The parameters of how film speed was calculated remained unchanged.

The reason why ISO and SX speeds are different is because they use two different measurement ranges. I also wrote an article on this subject too.

Xmas · Aug 13, 2015

Does every one know that TMAX in

D76 &
TMAX Dev

will have a different toe? Or have I misunderstood?

Note Kodak quote the same EI for both developers

RobC · Aug 13, 2015

It seems to me that no one has quite figured out that in order to make a 10 stop range fit grade 2 paper you have to reduce development. Everyone understands that bit I think. But what they never seem to grasp is that by reducing development you affect the toe of the film significantly enough that you have to reduce your EI to compensate. This has the knock on effect of pushing the exposure up the curve which in turn means you have to reduce development some more and that means you have to reduce EI some more and repeat until you get the right balance of EI and development.

The result is that you need to reduce EI by approx 50% in combination with the reduced development to make the zone system work as it is described by adams. His placement of zone 8 on a density of 1.3 still seems odd to me. But the practical evaluation test means you don't need to think about it.

Ian Grant · Aug 13, 2015

Xmas said:
Does every one know that TMAX in

D76 &
TMAX Dev

will have a different toe? Or have I misunderstood?

Note Kodak quote the same EI for both developers

There was a lot of fudgery by Kodak at the time Tmax100 & 400 were released, they weren't good processed in in D76/ID-11, they were superb in Rodinal, and later with Xtol though.

They were extremely good films although it's a shame the availability is so poor outside the main US and European markets. That's practical experience and you can always find Ilford & Foma B&W films, and a little Fuji.

Ian

ic-racer · Aug 13, 2015

Bob Carnie said:
So where are we all on base plus fog... does a print suffer from having a higher base density?

A little off topic, but base density decreases film latitude, until you eventually get to the point that it is all black and the exposure range is zero.

Small amounts of fog and narrow scene range would be likely not differ from the results produced with fresh materials.

David Allen · Aug 13, 2015

This thread has travelled a long way from the OPs question which was "Zone System - Find EI and dev time without resorting to densitometry".

The simple fact is that if you undertake what I refer to as 'real world' tests (as explained in my previous post) such variables as base fog, subject brightness range, contrast index are all rendered irrelevant because you are testing how the film reacts to your exposure metering technique, your particular way of processing film (including that great variable agitation) and your equipment.

The idea that the main manufacturers are 'lying' about their tested to ISO standards speed ratings is just rubbish. However, what is tested in a laboratory has little to do with how a film reacts to your usage in the field. For a simple example, when I used to teach at my Dad's Zone VIII workshops, it was not uncommon to find that one student with an Olympus OM1 with a ZUIKO prime lens had a completely different EI to someone else with a Olympus OM1 with a different manufacture's lens. The answer lay in each persons's equipment's variables and, to some extent, even their variable ways of ascertaining exposure with a hand-held meter.

As a second example, one of my students worked with me to test his Rolleiflex and we determined an effective EI of 400 for Tri-X 400. He later started also using his (untested) Nikon and got seriously underexposed negatives and could not understand why. When we tested the Nikon we determined (using the method I have previously outlined) that, for the Nikon, he required an EI of 160 for Tri-X 400. Why?? - well first of all the Rolleiflex had a lens with much less lens coating (meaning more flare) as the Nikon. Secondly, we will never know, but perhaps the Rolleiflex's speeds were not that accurate and the Nikon's were more correct.

The fact is, 'real world', testing reveals this straight away in a manner that ISO testing or densitometer testing will never do.

I remain convinced that testing using the equipment, film, exposure technique and chemicals that you plan to use is always the BEST way to make a quick advancement in your technical results. As to finding your way as a photographer - that is a life-long journey but please do not hinder this by years of 'technical' experiments - pin it down and get on with image making.

Bests,

David.
www.dsallen.de

Photo Engineer · Aug 13, 2015

You cannot fit the entire range of a negative film onto a print.

You might get 5 or 6 stops if you are lucky. If you use a paper with a soft toe and shoulder you might add another stop again if you are lucky.

See attached. Negative film on grade 2 paper. The negative film goes off the paper on the right headed for 3.0 which is the usual standard Dmax.

PE

Stephen Benskin · Aug 13, 2015

RobC said:
The result is that you need to reduce EI by approx 50% in combination with the reduced development to make the zone system work as it is described by adams. His placement of zone 8 on a density of 1.3 still seems odd to me.

From a Kodak publication. The answer is in there.

The 1.25-1.35 density range from The Negative is an entirely different story. Check out what the negative density range is in the Kodak diagram for starters.

Photo Engineer · Aug 13, 2015

Stephen Benskin said:
From a Kodak publication. The answer is in there.

View attachment 114594

The 1.25-1.35 density range from The Negative is an entirely different story. Check out what the negative density range is in the Kodak diagram for starters.

Yes, but in ancient Egyptian!

Just kidding Stephen, but who here can read that!

PE

Stephen Benskin · Aug 13, 2015

Photo Engineer said:
Yes, but in ancient Egyptian!

Just kidding Stephen, but who here can read that!

PE

It is from one of Kodak's publications for the general audience. Not sure which though.

markbarendt · Aug 13, 2015

Michael R 1974 said:
Xmas:

All I'm saying is that virtually every Zone System-type method will result in an EI somewhere around 1/2 to 1 stop slower than ISO, so there is little need for any testing on that front. You can just downrate by 1 stop, and fine tune based on print results.

What I've been trying to get across is the difference between understanding and not understanding Zone System EIs vs ISO. If you understand the difference, you know that Zone System EIs are predictably different than ISO speeds for known reasons. If you don't understand the difference, you think ISO is a nebulous conspiracy, and that the Zone System EI test is going to reveal something.

Back when sometime I had the great opportunity to spend a few days in Nevada with at least a dozen people I truly enjoy. We were being schooled by Per Volquartz and Jim Galli a bit. Something I sorely needed.

One of those days we ended up in an old courthouse doing a portrait of Per.

There was no shortage of meters at this gathering, nor opinion about how to meter.

What was amazing was that in the end we all agreed on the camera setting. Spot, incident, 1 degree and 5, shoot to the shadows and peg the mid tones.

We all agreed on the baseline EV, all our choices were workable, all our settings would let in the same amount of light.

The films we use are fixed entities with certain characteristics, latitudes, and limits. We can't fool the film we can only fool ourselves.

IMO, the magic of a finding a personal EI isn't technical, it is personal: it factors us into the equation; actually factors the way we think and the equipment we chose into the exposure equation.

RobC · Aug 14, 2015

Michael R 1974 said:
In a different thread we could debate the merits of compressing wide subject brightness ranges into negatives which print on grade 2....

It might be more educational to discuss what subject brightness range produces the most impactful eye pokingly good image on paper when hung on a wall becasue it won't very often be from a SBR of 10 stops IMO. With a head and shoulders portrait it may be as low as 3 to 5 stops.

[...]

Stephen Benskin · Aug 14, 2015

From The Theory of the Photographic Process:

"Small vertical arrows have been drawn at the bottom of Figure 22.2 to show the log luminance of some of the specular or, more properly, semispecular highlights with respect to a diffuse white highlights of the scene. Additional arrows would have to be drawn further to the right, beyond the limits of the graph., if the log luminances of the more intense specular highlights were to be indicated. The image of the sun reflected in shiny metal surfaces has a luminance more than one hundred million times greater than that of a diffuse white object. Experience with the use of transparencies to reproduce the appearance of the specular and semispecular highlights in relation to the other areas areas of the scene seems to prove that it is satisfactory to increase the luminance of the reproduction of a diffuse white object. Consequently, in Figure 22.2 the density difference obtained in reproducing the absicca points h and x should be 0.2 to 0.3 or slightly greater, if the transparency is to viewed with optimum lighting conditions.

Small vertical arrows have also been drawn at the bottom of Figure 22.2 to show the log luminance of shadow areas. The nominal shadow point is the point, s, which is the deepest shadow in which detail is visible in viewing the scene. To the left of s is the point, c, representing one of many small areas that can be called cavity shadows. They are deep crevices in tree trunks or between folds in dark clothing, shadows deep in bushes, or other small dark recesses in which no detail is discerible. Their log luminance values will sometimes fall far to the left of point c. Whether they are reproducing properly or not in a photograph is often of little importance.

The problem of deciding how to define log luminance range of the scene, for tone-reproduction studies, is usually solved arbitrarily by taking the log luminance interval between the deepest shadow in which detail is visible and the brightest diffuse highlight. Whenever this definition is adopted, however, it should be recognized that important semispecular and specular highlights and probably less-important shadows usually lie outside the log luminance range indicated."

Zone System - Find EI and dev time without resorting to sensitometry

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