zs clarification

[coops]

I have read a few good explanations of the basics of the zone system, but I am unclear about something. Many say that if one places important shadow detail on zone 3, and the highlight detail falls on zone 7, then develop normally because this is a five zone spread. But is this not a 4 zone spread? I would have thought zone 8 makes it a 5 zone spread. I am sure I am missing something.

[Nathan Potter]

No, think of it this way: Z-3, Z-4, Z-5, Z-6. Z-7. Five distinct shades of grey, each being a zone.

Nate Potter, Austin TX.

[coops]

No, think of it this way: Z-3, Z-4, Z-5, Z-6. Z-7. Five distinct shades of grey, each being a zone.

Nate Potter, Austin TX.

Okay, thanks. I was reading Bruce barnbaums book last night and he suggested placing important shadows on zone 4. Since I did my film testing using zone 8 for my highlights, may work out nicely. I want to give it a try today so thanks for the answer

[aduncanson]

My tongue-in-cheek answer was going to be that, being a pianist, Ansel counted zones the same way that a musician counts the interval between two notes. I think that Nate might be saying that I was right.

[coops]

No, think of it this way: Z-3, Z-4, Z-5, Z-6. Z-7. Five distinct shades of grey, each being a zone.

Nate Potter, Austin TX.

I thought my question was probably a dumb one, and this explanation makes sense, but I have read several books recently where the authors count zones III to VIII as five stops. Using the method quoted, this would be six zones difference. So as a newby I am a little confused as to which one is right, as I am sure it makes a difference between a good negative and a really good negative? Perhaps I am wrong.

[grahamcase]

There's a bit of difference between a "five zone difference" and a "five zone spread."

To me, a five zone difference could go from Zone III to Zone VIII, as the difference between them is 5.

Alternatively, a five zone spread could go from Zone III to Zone VII since, as Nate did, when you lay them out, there are five Zones you're working with.

Does this make sense to anyone? I'm a little sleepy right now...

[Roger Cole]

Yep, a "spread" is five zones inclusive.

[Leigh]

I have read several books recently where the authors count zones III to VIII as five stops. Using the method quoted, this would be six zones difference.
This is a universal problem that crops up in all disciplines; nothing unique to photography.

It's the difference between "points" and "intervals".

A ruler is 12 inches ("intervals") long, but it has 13 points if you count both the starting and ending marks.

There's always one more point than the number of intervals.

- Leigh

[Bill Burk]

I'd recommend following the examples in the book that you adopt. I think a great benefit of all ZS is the attention to giving shadows enough exposure and developing to control highlights. A nice side-effect is better record-keeping. If later you decide to change the system you adopt, you can always reconcile the different methods you tried by following your notes.

I adopted classic Minor White ZS from a booklet printed by letterpress where the graphics are cut in lead type. The example of N+1 is this:

---quote---

|..|..|..|..|..|..|..|..|..| =9 zones subject contrast

Negative contrast developed to

|..|..|..|..|..|..|..|..|..|..| =10 zones

Which fits the paper contrast full scale

|_|_|_|_|_|_|_|_|_|_| =10 zones

---end quote---

[Jim Noel]

There is more incorrect information on The Zone System in print, and evne more on the web.
Go to the source - either Ansel;s book "The Negative", or "On Portraiture" by Ansel's original partner in developing the system, Fred Archer. Archer's book is very short and simple to understand.

[Don M]

Coop,

<...makes a difference between a good negative and a really good negative...>

FWIW, here's how I think about it; it's in relation to the characteristic curve of the negative; the paradigm being an S-shaped curve.

The low values are captured closer to, or at, the "toe" of the curve (where it's not very curvy) and the high values will end up at the "shoulder" of the curve (another place where it's not very curvy). In between is a relatively straight line.

Values that end up on the toe (low values) or shoulder (high values) will be compressed, with less separation between them, compared to values that end up on the straight portion of the curve. Values that do not have good separation have less information.

Exposure mostly affects the low values. Exposure will set where low values end up on the curve (usually the toe ranging into the straight line portion). For high values, exposure and development together control where they fall on the curve (usually from the straight line ranging into the shoulder). [Development will have some effect on the low values, but that factor is usually ignored.]

For any given combination of 1) subject brightness range, 2) exposure, 3) development, you can see that a photographer can shift that range up and down along the film curve.

When someone talks about exposing important low values for Zone III or Zone IV, what they are saying (and all that they are saying) is, for that part of the subject, they want to be sure they record enough information, far enough up along the curve (away from the poorly separated toe area) to be sure that information will show in the print [and, in the ideal situation, with latitude to allow for alteration through printing procedures]. But, of course, the higher you place the low values, the greater the risk you will move your important high values too far up on the shoulder (because of the inherent subject brightness range between high and low combined with the amount of development you give the negative). Values that end up too high on the shoulder become "blocked" and will only print as extremely light grey or pure white, without detail of any kind. (Again, information loss.)

A "good" negative in this sense doesn't mean that you are necessarily dealing with great subject matter. It only means that, because of your choices as to 1, 2 and 3 above, the negative contains enough information in the low and high values [I]that were of importance to you when you exposed and developed the negative, that, in making the final photograph, you will be able to print the negative as you wish on photographic paper (or a computer monitor, if that is your goal for output).

In that limited sense, a "good" negative becomes (in theory!) easier to print the more the important subject ranges (low and high) end up on the straight line portion of the film's curve. On that portion of the negative, you know you will have good (ie, printable) detail and good separation of tones. And then it's up to the printing of the negative to keep or to change those values, depending on your artistic intention for the final print.

This stuff is far more cumbersome to write about than it is to understand.