Zone system mathematically inconsistent

[CMoore]

And that is the nice thing about negative film. It has a huge latitude if you expose normally in the center of the curve on the straight line portion. Normal development will give you about 1 stop on either side and so you normally (with mainstream films) don't have to adjust the development time and push or pull.

With 3rd tier films, they often achieve speed by higher contrast and there, you are out of luck!! With Ilford, Fuji and Kodak, you will not have to adjust development time.

However.... for those who prefer to adjust, I always suggest a test roll with their favorite film and running push and/or pull processes on the film before shooting with a given film.

I have run test with films from most major manufacturers and many small ones to verify this with a variety of films.

PE

Right.... OK.
That makes sense with the Latitude/Exposure i was asking about.
As you say, i suppose testing is always the final word.
Thank You

 

[Photo Engineer]

Actually Theo, this was both before and after due to film design changes. It was due to the ability to supersensitize films which came on-line at about that time.

PE

 

[bascom49]

why I have been having trouble understanding the finer points of the zone system

For an average seen with six to eight stops of range:
1) Meter for shadow areas, close three stops or four, your preference for detail.
2) Not enough detail, decrease EI the next time you shoot. Too much ? Increase EI the next time you shoot.
3) Not enough high light detail, increase development time the next time you develop. High lights blown out, decrease development time the next time you develop.
4) Understand typical Zone Values - Zone V Middle, Zone VII Bright, Zone II Dark. Zone I Black, Zone VII White, Pick meter and adjust.
5) Unsure ? Wing it and don't miss the picture or waste time fretting.

From Ansel Adams, in Examples:
“I had been photographing in the Chama Valley, north of Santa Fe. I made a few passable negatives that day and had several exasperating trials with subjects that would not bend to visualization. The most discouraging effort was a rather handsome cottonwood stump near the Chama River. I saw my desired image quite clearly, but due to unmanageable intrusions and mergers of forms in the subject my efforts finally foundered, and I decided it was time to return to Santa Fe. It is hard to accept defeat, especially when a possible fine image is concerned. But defeat comes occasionally to all photographers, as to all politicians, and there is no use moaning about it.

We were sailing southward along the highway not far from Espanola when I glanced to the left and saw an extraordinary situation—an inevitable photograph! I almost ditched the car and rushed to set up my 8×10 camera. I was yelling to my companions to bring me things from the car as I struggled to change components on my Cooke Triple-Convertible lens. I had a clear visualization of the image I wanted, but when the Wratten No. 15 (G) filter and the film holder were in place, I could not find my Weston exposure meter! The situation was desperate: the low sun was trailing the edge of the clouds in the west, and shadow would soon dim the white crosses.

I was at a loss with the subject luminance values, and I confess I was thinking about bracketing several exposures, when I suddenly realized that I knew the luminance of the moon—250 c/ft2. Using the Exposure Formula, I placed this luminance on Zone VII; 60 c/ft2 therefore fell on Zone V, and the exposure with the filter factor o 3x was about 1 second at f/32 with ASA 64 film. I had no idea what the value of the foreground was, but I hoped it barely fell within the exposure scale. Not wanting to take chances, I indicated a water-bath development for the negative.

Realizing as I released the shutter that I had an unusual photograph which deserved a duplicate negative, I swiftly reversed the film holder, but as I pulled the darkslide the sunlight passed from the white crosses; I was a few seconds too late!”


Finer Points:
6) Small dynamic range - Increase development time
7) Large dynamic range - Decrease development time

Finer, Finer Points:
8) Agonize incessantly over logs, graphs and sensitometry
9) Spend all of your time testing.
10) Spend the rest or your time graphing and curve plotting.
11) Spend no time actually being a photographer.
12) Gain perspective by reading works by Kurt Godel, go back to steps 1 thru 5 and return to photographic happiness again.

 

[Sirius Glass]

Finer, Finer Points:
8) Agonize incessantly over logs, graphs and sensitometry
9) Spend all of your time testing.
10) Spend the rest or your time graphing and curve plotting.
11) Spend no time actually being a photographer.
12) Gain perspective by reading works by Kurt Godel, go back to steps 1 thru 5 and return to photographic happiness again.

Or choose the dark area that you want to keep the detail, then determine the Zone you want that area to be. Use a spot meter to measure the light and set the dial on that Zone number. Read off the value of Zone 5 and use that to set the camera. Adjust the setting for any filters.

 

[alanrockwood]

...Now, all you have to do is center the exposure on the straight line, using the ISO on the box, and away you go. I know this because I helped design the product and assign the ISO value, so I know it works...
PE

Yes, that is basically the approach I advocated, centering the exposure on the straight portion of the line, or to put a fine nuance on it, I suggested putting it on the straightest portion of the line and letting the highlights and shadows fall where they may. (Of course, one may want to increase or decrease the exposure relative to the indicated meter value if the primary subject matter is especially light or dark, but that is the topic for a different conversation.)

As for the iso part of what you said (using the iso on the box), if one is using a film/developer combination for which that is known (e.g. the manufacturer has done the work) then that is fine. However, if one does not know the best exposure index to use for a given film/developer combination, that is where personal film testing comes in, at least for those who care.

There is also the part about what contrast to shoot for in the negatives if one is doing their own testing of a film/developer combination. That choice is up to the person doing the testing, and there are endless discussions on the internet about what contrast is best. Of course, if one is using the full-blown zone system with expansion and contraction during development then there is not a single answer to the best on-film contrast that would cover all situations.

Returning to my original point, if we think about the usual description of zone 8 (e.g. able to see some detail in the highlights), that is a physical impossibility for a zone 8 object that is an ordinary diffuse reflector, such as non-glossy paper, ice cream, etc. Most non-glossy objects fall into that category. This is true regardless of whether the reference point for zone 5 is 18% reflectance or 12.5% reflectance. (For a 12.5% zone 5 standard, zone 8 would be a 100% reflector, and there is no detail to be seen in a diffusely reflecting object with a reflection of 100%. For a 18.5% zone 5 standard zone 8 corresponds to 148% reflection, which is a physical impossibility for an ordinary diffuse reflector.)

The point is, you can't reconcile the qualitative description of all of the zones (e.g. some detail in zone 8) with physics and math, so don't even try to understand the zone system in terms of rigorous physics and math, at least not in zone 8 and above. At best just use it for qualitative conceptual guidance, or ignore it altogether. Also, if you are wondering why you can't square the zone system with physics and math take comfort in the fact that the inconsistency is inherent in the system.

There is actually one way to let some consistency creep back into the zone system if you change the qualitative description of the higher zones a little, for example by defining zone 8 to include some glare (i.e. specular reflection) into the definition of zone 8.

One final point. The discussion of the zone system presented above assumes a concentrated light source so that specular reflections are relevant. I won't go into the details, but basically for a diffuse light source (approximated by a cloudy sky) you can't quite reach zone 8 any way you slice it.

 

[Photo Engineer]

With a 21 step scale, there are effectively 7, 7.5, 8, 8.5, 9 steps and etc. Does that help??

This is how I did it.

 

[KN4SMF]

What are some examples of "3rd tier" films?. Would Arista edu ultra 400 for example be one? And I've always maintained that the scientists at places like Eastman Kodak were making products that were highly tested for the ease of the customer.

 

[Bill Burk]

alanrockwood,

I think you temporarily thought of everything at once. Think of the subject and the print separately. (You can separately consider the negative as well.)

What you say applies to graphic arts flat artwork reproduction. If you have a flat paper subject and your intention is to reproduce it exactly. Then the white 100% subject has to be white on the print, likewise the black on black.

But when taking a picture in three dimensions, your print will have a light gray Zone VIII reproduction, Zone IX can be paper white. Likewise in the shadows Zone III won’t be pure black, it’s going to be dark gray and although the contrast is less in the shadows, you will be able to distinguish something in Zone II and maybe Zone I. That’s just straight print of a Normal scene and development on Grade 2 - Nothing fancy. Normal pictures are flatter than the original scene to give the illusion of the original scene, but it’s not a 1:1 tone reproduction of the original.

I think you confused the subject with the print instead of considering the different parts of the tone reproduction cycle.

 

[Bill Burk]

Here’s a thread where I demonstrated that thought. Actually the paper white is the lightest key tone in my print. I don’t think that ruins my point but funny how you can talk about things and you can try things and come to different conclusions.

https://www.photrio.com/forum/threads/12-subject-looks-right-printed-to-match-18-gray-card.136266/

Here’s the corresponding sensitometry. There’s a lot going on in the shadows beneath paper black. The paper black is lifted to dark gray.

http://beefalobill.com/imgs/tmxaim.jpg

 

[KN4SMF]

Bill Burk's presentation above is good work. Ive done tests myself not unlike his and can testify it's good work. Ansel Adam's original system was based on a flawed concept.That's not to say it was bad or useless by any means; in fact was very enlightening. There was more good than bad about it. But it was originally based on a Westom Master meter used in reflectance mode.I don't think Adams had any inkling of the lack of color linearity capabilities in that meter and every other exposure meter since. I've done my own exhaustive testing of color response in exposure meters, and it was shocking. I concluded that the Zone System was a useful way of visualization, but far from exact. The point being, do your best, but even that will only be so good. It's all you can do. Adam's work was a 10 zone system. and the film engineers use a 21 zone system. "Middle gray' for the average photographer is many times a 3rd Standard, and only for the one particular print.Once again a good print doesn't necessarily have anything to do with any system.

 

[cowanw]

Reminds me of the time dad took a picture of my brother and I with his Brownie box camera. I was standing in the shade, under a porch, holding up a Kodak grey card. My brother was 4 feet to the side, in direct sun, holding up his identical grey card. When we got the picture back, we had two identical grey cards which were simultaneously 18% reflectance and also two quite different shades of grey. I think my dad's box camera was actually a Schrödinger's box camera.

 

[Photo Engineer]

What are some examples of "3rd tier" films?. Would Arista edu ultra 400 for example be one? And I've always maintained that the scientists at places like Eastman Kodak were making products that were highly tested for the ease of the customer.

Anything not named in my list, probably fit that definition. And yes, we did a LOT of testing.

PE

 

[KN4SMF]

What list? Where?

 

[ic-racer]

I don't know why I didn't realize this before, but I think I finally understand part of the reason why I have been having trouble understanding the finer points of the zone system, at least in a quantitative sense. The reason is that it makes no sense in a quantitative sense, assuming we discuss it in terms of powers of two. By this I mean that if we assume that each step in the zone system corresponds to a power of two in exposure then the system is mathematically inconsistent.

Let me explain. Let us assume, for example, that an object that of 100% reflectance is placed in zone 9. Then 50% reflectance (corresponding to a one f-stop difference) would be in zone 8, 25% reflectance would be in zone 7, 12.5% reflectance would be in zone 6, and 6.25% reflectance would be in zone 5. Here is the inconsistency. Zone 5 is commonly said to correspond to 18% reflectance, but the 6.25% number we get by counting down from zone 9 is only about a third of 18%. Therefore, the zone system is not mathematically consistent.

My conclusion is that, while the zone system may be qualitatively/conceptually useful, it is not quantitatively correct.

The "Zone System" is a "Black Box" tool for the non-scientific. A study of basic sensitometry gives the correct answers.

 

[Photo Engineer]

What list? Where?

I listed my idea of First Tier manufacturers above in this thread. They are Ilford, Fuji and Kodak. Then there are 2nd tier and 3rd tier IMHO. EFKE was 3rd tier.

PE

 

[alanrockwood]

I listed my idea of First Tier manufacturers above in this thread. They are Ilford, Fuji and Kodak. Then there are 2nd tier and 3rd tier IMHO. EFKE was 3rd tier.

PE

In my non-expert opinion Agfa might also have been first tier at one time. Ferrania (as it existed at that time) was probably second-tier.

Today there aren't as many companies to choose from. I would like to put Foma into second tier, but realistically it is probably better put to Foma into the third tier, based on technical qualities of their products in comparison to products from first tier companies (film speed/grain/reciprocity characteristics) as well as past QC issues of the film products. However, I use Foma film, though not exclusively, and some people prefer it.

Even the first tier companies are just shadows of what they once were. For example, a few years ago I contacted Ilford and asked a fairly simple technical question about their variable contrast enlarger papers, but from the response it was clear that the technical knowledge I sought had been lost along the way.

 

[Bill Burk]

There’s cottage tier as well! Like Jason Lane dry plates.

alanrockwood I hope you feel differently now that what you thought was impossible about Zone System is OK.

Flaws, sure. Like it doesn’t address flare. I think it’s wasteful to shoot extensive film tests following Zone System procedure just to avoid buying a seven dollar step wedge.

But fundamentally it is OK.

 

[Dali]

I listed my idea of First Tier manufacturers above in this thread. They are Ilford, Fuji and Kodak. Then there are 2nd tier and 3rd tier IMHO. EFKE was 3rd tier.

PE

You said too much or too little to be clearly understood.It would be interesting to know what you define 1st tier from 2nd tier from 3rd tier product... QC, films features, films consistency, something else?

 

[Photo Engineer]

In my non-expert opinion Agfa might also have been first tier at one time. Ferrania (as it existed at that time) was probably second-tier.

Today there aren't as many companies to choose from. I would like to put Foma into second tier, but realistically it is probably better put to Foma into the third tier, based on technical qualities of their products in comparison to products from first tier companies (film speed/grain/reciprocity characteristics) as well as past QC issues of the film products. However, I use Foma film, though not exclusively, and some people prefer it.

Even the first tier companies are just shadows of what they once were. For example, a few years ago I contacted Ilford and asked a fairly simple technical question about their variable contrast enlarger papers, but from the response it was clear that the technical knowledge I sought had been lost along the way.

Agfa would certainly have been first tier when they existed as a company. I did not mean to leave them out for any other reason than they do not exist at the present time.

All manufacturers are shadows of their former selves. Believe me.

PE

 

[Photo Engineer]

You said too much or too little to be clearly understood.It would be interesting to know what you define 1st tier from 2nd tier from 3rd tier product... QC, films features, films consistency, something else?

I posted, once upon a time, a huge 16x20 piece of Efke film. On that slice of film I saw dirt, dust and bubbles along with a repeating coating defect caused by some surge in speed of the machine or pumps that left a sinusoidal wave in the film of heavy and light coating. That is a 3rd Tier company for sure. For the rest, I prefer not to judge. I have given 3 from the first tier and one from the 3rd.

PE

 

[Paul Howell]

I listed my idea of First Tier manufacturers above in this thread. They are Ilford, Fuji and Kodak. Then there are 2nd tier and 3rd tier IMHO. EFKE was 3rd tier.

PE

As I understand the current situation Ilford is custom coating for Bergger and maybe Ultrafine, paper for B&H multitone, so are these first or second, or third tier?

 

[alanrockwood]

As I understand the current situation Ilford is custom coating for Bergger and maybe Ultrafine, paper for B&H multitone, so are these first or second, or third tier?

I can't answer for PE, but it seems to me that a product coated by Iford under contract could be considered first tier.

 

[Photo Engineer]

As I understand the current situation Ilford is custom coating for Bergger and maybe Ultrafine, paper for B&H multitone, so are these first or second, or third tier?

If it walks like a duck and quacks like a duck......

Most of the problems are in coating and things related to coating.

PE

 

[Bill Burk]

There were other "qualities" that Kodak put into film that other manufacturers didn't. In one of my jobs before working for Kodak I ran an imagesetter that ran 20 1/2 x 25 1/2 in film.

Kodak's film for it could always reach 4.0 density, the 3M film never got much more than 3.6

 

[Photo Engineer]

ILM was all over us for insufficient density in our MP products so we fixed that in a number of films.

PE