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panoral
9-Jul-2015, 23:46
"The Zone System is a framework for understanding exposure and development and visualizing their effect in advance. Areas of different luminance in the subject are related to exposure zones, and these in turn to appropriate values of gray in the final print. Thus careful exposure and development procedures permit the photographer to control the negative densities and corresponding print values that will represent specific areas, in accordance with the visualized final image." Ansel Adams
http://www.mr-alvandi.com/technique/zone-system.html
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koraks
10-Jul-2015, 05:59
I think virtually everyone on hear knows about the zs and uses it either extensively, or as a frame of reference or inspiration. Do you have a particular question or issue you want to bring up?

Heroique
10-Jul-2015, 13:16
The second image is a useful illustration for beginners.

However, its formatting seems to plagiarize AA's illustration in The Negative. (See "The Zone System" chapter, page 54).

The similarity is enough to make lawyers drool. ;^)

Ulophot
10-Jul-2015, 18:11
I did not ref the entire page, but frm a scan, it appears that the author uses both the original and Adams's later modified system, i.e., the former with Zone 1X as pure white and the latter extending to Zone X for pure white, due to advances in film emulsions. I don;t know if he differentiates for the reader.

Bill Burk
10-Jul-2015, 19:32
panoral,

This seems like an announcement of your web site explaining Zone System and showcasing your photography.

Well done! It looks good and you are sharing what you know.

panoral
11-Jul-2015, 06:42
Thanks to everyone, I have prepared this article for my website.
Of course, I experienced the zone system. I hope to know, advise others about this article.

Fotocat
11-Jul-2015, 12:56
Panoral,
Your web page, and all it's attached techniques, is a great source for everyone on this forum. Good work!
Fotocat

panoral
12-Jul-2015, 08:42
Thanks, Fotocat.

Stephen Benskin
14-Jul-2015, 22:58
It's a well designed site. Since you are introducing it on a technical forum, I thought you might like some technical feedback. You use ASA when you should be using EI. Meters don't "see" 18% percent. Under statistically average conditions, it's 12%, but it really uses luminance. Gamma is not the best way to determine contrast. Average gradient methods produce more consistent results. And just an FYI, stopping down four stops from the metered exposure is part of ZS methodology but does not equate to the ISO standard. This distinction brings into question how appropriate it is to call the section "calculating film sensitivity" or even calculating film speed when it's more about finding a personal EI.

The part on development time doesn't appear to state or take into consideration the printing conditions. The aim densities are definitely beyond what is considered normal, and based on the following statement, you are definitely misinterpreting film curves.

"If α angle is equal to 45 degrees, the tangent α is equal to 1 and negative has normal contrast. If α angle is less than 45 degrees, negative has soft contrast, and if more than 45 degrees, the contrast will be hard."

Normal gradient should be around 0.58 or slightly over half the subject contrast. Gamma usually produces a higher number for the same curve. If the straight-line is at a 45 degree angle, it is producing a 1:1 relationship with the subject contrast. If this reflects your process, I can't see how you are producing printable negatives. I assume you are, so you either don't actually plot your test results and this section is just bad theory, or your densities are inaccurate.

Cor
15-Jul-2015, 02:33
A bit OT, but check Mr Alvandi his other Web pages, especially his home made cameras look very nice and interesting! Nice job Mohammad !

best,

Cor

panoral
16-Jul-2015, 08:30
Stephen Benskin,
Thanks for your helpful comment. Of course, in some cases I do not agree. But, I'll investigate on it.

panoral
16-Jul-2015, 08:30
Cor, Thanks for your comment.

Drew Wiley
16-Jul-2015, 12:01
Most gray cards are based upon 18% gray, not 12%. But very few of them are consistent in refectance or gray neutrality, even from the same manufacturer, though you can get better quality ones from serious color control outfits like MacBeath that have a standardized range of neutrals grays, including 18% and 12%.
I once measured stacks of such products on a high-end continuous-tone spectrophotometer to find out the truth. But this kind of fact might just complicate things
for a beginner trying to learn the Zone System to begin with, as would be anything especially quantitative beyond basic shutter speeds, f-stops, ASA etc.

Stephen Benskin
16-Jul-2015, 19:42
Let me know what you don't agree with and we can have a discussion. If it's about exposure meters, you can find the answers in D. Connelly, Calibration Levels of Film and Exposure Devices (http://64.165.113.140/content/benskin/).

Below are a couple of pages from a series of posts on exposure I put together. You can find the complete series Defining K also at the above link. You can clearly see at the bottom of the second page that R = 0.12.

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If you are wondering about what gradient is considered normal. I've attached a paper I wrote on the subject. Notice how your 1.0 gradient for normal actually equals around a +3.

Louis Pacilla
19-Jul-2015, 14:10
Man that is something Alvandi! You not only made your own 1*spot meter (along w/ numerous other photographic gear including a couple of awesome cameras) but you also made your own studio mono blocks and it all looks very well made. Your web site is terrific and on top of it all you make very nice images as.

Thanks for sharing with the LF community.:)

panoral
20-Jul-2015, 07:23
Drew Wiley, thanks for comment. Yes, most gray cards are based upon 18% gray. I know it. If, I say somewhere, please show me. Of course, I measured, gray tone values with a spectrophotometer and compare with my densitometry. Thanks

panoral
20-Jul-2015, 07:49
Stephen Benskin,
Thanks for your post. It was very interesting articles. I've downloaded all of them. But my purpose of my article, is the simplicity and applicability of the zone system. I think we should not discussion about the zone system and the sensitivity of the film into mathematical problems. Because it will lead to complexity and difficulty. I think photographers should be try to use a standard procedure to his work. Therefore, he will assess the aesthetic issues.
Thanks

panoral
20-Jul-2015, 08:08
Louis Pacilla
Thanks for your interest in my website. I have tried to provide the necessary information to analog photography. This information should be practical and easy.
Of course, I made several of large format cameras and camera accessories. They are made of aluminum alloy with machining.

Also, I've produced a spherical panorama head, which is available for sale in Iran. This panoramic head, is very lightweight and portable.
All stages of production is done by myself. (Design, machining, plating, assembly, packaging and instruction manual)

Stephen Benskin
20-Jul-2015, 10:52
The math is there as a proof. Without it, the 12%/18% debate could go on forever. I've shown that meters "see" 12%. You don't need to use the math, but you should incorporate the conclusion.

Drew Wiley
20-Jul-2015, 11:19
There is nothing precise about "zones". That why they're called zones to begin with. It's a kind of shorthand teaching method. But God didn't create light in zones,
and film curves aren't chopped up into discrete segments like a beetle or even a centipede. To be precise at this, you'd have to plot a different zone system for
every single combination of film and developer, under every different variable, calculus integers and all; and about all I understand about calculus is that's it's
something dental assistants remove from your teeth. Besides, thinking about a bunch of math is that last thing I need to be doing when taking a shot. At that point
in time, everything has to be spontaneous, second-hand. Lab sensitometry can be as involved as you like; but there's a time and place to be simple too. And the
more simply the Zone System itself can be explained and applied, the better.

Drew Wiley
20-Jul-2015, 11:25
Stephen - I'm unaware of any film meter I've ever used that even sees in neutral gray. I do own a very expensive lab instrument that does. Many of our popular
meters, like the Pentax spotmeter, were designed with color cinema sets in mind. In this case the peak sensitivity is close to that of the human eye, atop the green
part of the spectrum. But different receptors, esp in the past, had their own spectral sensitivities. After awhile, people just get used to the idiosyncrasies of their
meters, I guess. And for those who use gray cards, well... I've found those to be all over the place in terms of alleged quality control, everywhere from 11% to
25%. Might as well be reading the back of your hand, like old timers did!

Stephen Benskin
20-Jul-2015, 13:12
12% Reflectance, not 18% Reflectance. Please refer to the defining K compliation.

Drew Wiley
20-Jul-2015, 14:11
Reflectance per WHAT, Stephen? With a spectrophotometer, there's typically an unfading calibration tile (or generally two). In nature, one only approximates gray as best one can. I'm accustomed to reading conifers and various shades of grass. Up in the mountains you've got various shades of diorite and granite etc. One bends meter technique to what one has, just like one bends the Zone System in any manner it works for him personally. I learned it, so now I can ignore it. Real sensitometery needs to be done under controlled circumstances. I shoot in uncontrolled circumstances, with the light often changing every few seconds. Don't have time for calculators or any kind of nonsense. The film curve and its development are all in the back of my head somewhere. It either fits or it doesn't. The most I ever want to worry about, besides the basic exposure itself, is segregating odd sheets of film for a slightly different development regimen.
After all, that's all the Zone System boils down to, once you master it. No sense making a religion out of it. It's about practical photography, not R&D.

Stephen Benskin
20-Jul-2015, 17:36
Reflectance per WHAT, Stephen? With a spectrophotometer, there's typically an unfading calibration tile (or generally two). In nature, one only approximates gray as best one can. I'm accustomed to reading conifers and various shades of grass. Up in the mountains you've got various shades of diorite and granite etc. One bends meter technique to what one has, just like one bends the Zone System in any manner it works for him personally. I learned it, so now I can ignore it. Real sensitometry needs to be done under controlled circumstances. I shoot in uncontrolled circumstances, with the light often changing every few seconds. Don't have time for calculators or any kind of nonsense. The film curve and its development are all in the back of my head somewhere. It either fits or it doesn't. The most I ever want to worry about, besides the basic exposure itself, is segregating odd sheets of film for a slightly different development regimen.
After all, that's all the Zone System boils down to, once you master it. No sense making a religion out of it. It's about practical photography, not R&D.

What I am talking about is theory (Exposure and Tone Reproduction). The math is there to explain it. Just like the Zone System (simplified Tone Reproduction Theory), understanding how the process works makes it easier to use. If you take the time to read my Defining K, you might begin to understand. Exposure meters want to place 8 lx on the film plane. Incorporate the film speed and you get 1/ISO * 8. The constant 8 can be referred to as P. So for a 125 speed film, 8/125 = 0.064 lxs is the midtone exposure. B&W speed point is Δ1.0 log-H units below the mid-tone exposure point. The speed equation is 0.8/Hm. Hm for a 125 speed film would be 0.8/125 = .0064. The following table shows the exposure breakdown for a 7 2/3 stop luminance range (the average is 7 1/3, but I add 1/3 of a stop to help illustrate flare). The RD that produces the 0.064 lxs film plane exposure is 0.92. Anti-log of that is 0.12 or 12%.

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And the 297 cd/ft2 is derived from the exposure meter standard when K = 1.16 cd/ft2 or as your exposure meter might list it as 12.5 cd/m2.

BTW, one of the papers in the link, An Interpretation of Current Exposure Meter Technology has a large section on photo cell spectral sensitivity and color temperature. Here's a graph from the paper you might find interesting.

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All I'm doing is correcting some mistakes by the OP. He says meters see 18% reflectance. They don't. He claims a Gamma of 1.0 is normal. It isn't. I simply supplied the information supporting my position.

Stephen Benskin
20-Jul-2015, 17:49
Panoral, below is an example of a four quadrant reproduction curve. Notice how the original luminance range of 2.20 is reduce within the camera, by flare, The film is processed so that the resulting film density range matches the paper log exposure range. To print the average scene on a grade two paper, the gradient for this example is 0.56. The resulting tone reproduction gradient averages around 1.0. This curve is derived from comparing the original subject to the print.

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panoral
24-Jul-2015, 05:55
Thanks to all. It was very useful information.