I am in the process of trying to do some film tests according to the Zone System in 35mm. I think understand the concept - Find the correct film speed that gives you detail in Zone 3, then find the development time that gives you good detail in Zone 8. Then it all got turned on its ear when I was reading a thread at P.net and someone mentioned Barry Thornton's "Edge Of Darkness". He sais that for depending on the brightness of the scene, rate the film at box ISO (cloudy, no shadows) and develop as recommended, and to rate the film at 1/2 box iso and decrease development by something like 20-30% (bright sun, sharp shadows). I thought that film testing was to give you the film's speed, regardless of the light outside! Is his vernacular just another way of deciding on exposure and N minus development for scenes that have a long exposure gradient for "non-zonies"? I'm trying to wrap my head around his use of box ISO for cloudy scenes and normal development though. It seems that film is always slower than its box ISO.....
I have not read the Thornton book but based upon what you say, it appears to eliminate testing film speed.
I will go on to say that film speed is not a fixed factor (no matter if this is Thornton's recommendation or that of Ansel Adams or someone else who claims this to be true). Film speed will vary depending on development. Development is of course tied to the inherent scene brightness.
Film speed is not always slower than box speed. It depends on development.
Tim, Thornton's method is just a heuristics, simplified way of dealing with expansions and contractions. It's just based on statistics of usage, not on actual sensitometric data. The point is that most 400 ISO film usually end up being closer to an EI 200 in practice. All the rest of his calculations are relative to this regularity, but it's a shortcut, not actual knowledge about your film.
If you want to know how your film behaves, you have to go through the experimental process of EI/dev time using whatever method you see fit.
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My understanding of the method desrcibed in that book is that it is the old "Expose for the shadows, develop for the highlights" method. I should also add that I use this method and it has greatly improved my ability to control my negatives. I now get negatives that are always in the 2-3 range with roll film, and almost always right on 2 for sheet film where before I was ranging from 0 to 4 on any given roll. It's not as precise as other methods, but I've seen photographs that are stunning which were made before light meters existed so I'm no overly concerned about it myself. Everyone has a system that works for them, I would suggest that you try it out and see what you think before discounting it.
Last edited by reellis67; 02-07-2007 at 04:51 PM. Click to view previous post history.
An old professor of mine used the same system. I used it a couple of times, and it worked quite well. This has to do with increasing contrast with increased development. So to get a standard amount of contrast from scenes varying in contrast(on different rolls, mind you). You use this expansion/contraction development. For more contrast: underexpose/overdevelop, for less: overexpose/underdevelop. If you want sensitometric data, I might be able to dig it up, let me know.
Originally Posted by timbo10ca
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There are lots of film testing methods to get a good personal film speed and development time. Ansel Adams and Phil Davis are a couple of others who have given good, reliable methods in their books. Barry Thornton was a very practical photographer. He has given two fairly easy ways to go. The first you mention (find the exposure that gives good detail in Zone III then find the development that give good detail in Zone VIII) is a practical formal method that is generally equivalent to any of the others. It requires selecting an appropriate test scene, some real testing, and some patience, but, done right, it will guarantee good results from that combination of film and developer. The second (rate the film at 2/3 to 1 stop less than the ISO value and develop 20 - 30 percent less than recommended) is a rule of thumb he found worked with most films and developers. You may have to tweak it a bit for your technique, but it will generally work.
Basic concept of the ZS:
The placement of a particular reflectance within the scene on a particular zone within the scale of zones i.e., usually from zone I to zone V. Read Fred Picker's Zone VI Workshop. It's great for someone new to ZS (get AA's "The Negative" for that matter, but I would start with Picker's book first). You do not have to find a personal film speed right off the bat to be able to use the ZS, although you should eventually become aware of what to do when your low value placements do not yield the density in the negative that you anticipate.
I recommend rating your film as per the box speed, practice with some low value shadow placements for exposure (would be best if your 35mm camera has some degree of spot metering), develop the film as per the manufacturer's recommendations. I personally would not be messing around with film testing and variable development until you have a firm grasp of the basic tenet of the ZS: i.e., the "placement" of values on the exposure scale and determining where other values "fall" (a spot meter makes such determinations easier, however).
These are just some suggestions. When I was learning the ZS, I did exactly that----I rated my film as per the box speed, developed as per recommendations for the developer I was (and still am) using. I did this until it became intuitive as to what was occurring based on my actions. Then other aspects such as plus/minus development, filtration, etc...gently fell into my understanding. I'm a 120 user and I'm getting along just fine with ZS "stuff".
Just a suggestion---good luck and regards.
If you want the late, lamented, Barry Thornton's thoughts on testing go to the website www.barrythornton.com - it was put back online after his demise by AWH Imaging (Andy Hollingsworth).
There are several articles on film testing there that go beyond the general "expose for the shadows, develop for the highlights" advice.
I have been looking at film testing information too and I found this quite interesting: http://www.halfhill.com/speed1.html
Last edited by Steve Smith; 02-08-2007 at 04:38 AM. Click to view previous post history.
Reason: Added second part
Originally Posted by Chuck1
I've actually done exactly as you say, but I started off by reading the entirety of Lewis Downey's website http://www.zonesystem.com/ and practicing with his emulator. I felt I had a very good handle on the ZS, other than pre-exposure at that point. I bought and read all 3 of AA's books, and now feel that the whole ZS is quite intuitive, and I just have to practice it to get the nuances. I've been using only FP4+ with only Ilfosol S since the 1st day I developed my own film. I feel familiar enough with these products, and my ability to make a proper contact sheet to say that I am underexposing the vast majority of me shots, and I've been applying the basics of the ZS all along regarding exposure. I've been using 35mm film, and my camera has a spot meter.
I have not determined N or N- or N+ development yet, because I have only just recently come to the point that I need to start film testing. I have no access to a densitometer. My 1st film test was using Steve Simmons' technique in "Using the View Camera", but in retrospect I realize I goofed it up. I still have not tried N, N- and N+ tests yet, as I am just starting to flub my way through the whole tesing process. My film rating (flawed as it is) put the FP4+ at ISO 64, so I am almost inclined to believe it.
I'm getting to the point where I feel as though I have information overload, and just have to take a step back. There are too many ways to do the same thing, but the most accurate seem to be using a densitometer. I have an enlarging meter from RH Designs on its way, and it is supposed to allow me to do this.
Essentially I am trying to get a method figured out that I can believe in and stop questioning (I went through the same thing with the Sunny 16 Rule), as I have just aquired a 5x7 camera and don't want to be wasting a bunch of film. My BTZS book and DVD came in the mail yesterday. I will get through it (although it looks like a dry read), and probably send my LF film and paper out for testing. I will also get the Picker book because it is so highly recommended, but I've got to stop reading everything that is recommended and start doing. There must be 8 more books I've been recommended to read.
I started this thread because just when I though I understood what I was doing, this concept seemed to turn thigns on its head and I needed some clarification.