Zone System 2

A book called, The New Zone System, gave me some ideas to use. I shot a roll of new Tri-X 400 in my Pentax 6×7 of a gray card exposing it at every setting so that I could figure out the ASA. The least exposure was made. A gray card correct exposure was made and a blank frame was made. Then a series of exposures were made in 1/2 steps. Zone 1 is four stops closed from the gray card. I went past 800  ISO a full stop and past 200 ISO a full stop.

One of those exposures would show me the optimal ISO to use the film at. But which one and how was I to determine which one?

More tests were needed. Photo paper was totally exposed to bright light and developed to a maximum black. Another sheet was not exposed at all and fixed as is. That gave me a maximum white sheet. Then wedge tests were made using the blank negative.


A step wedge test was made to determine the time needed to expose paper through a blank negative to maximum black. The enlarger was positioned to make an 8×10 print even though 4×5 paper was used. It was focused on the grain in a frame that had a gray card visible in it. Then the blank frame was put into the negative carrier. The iris was set to f22. Two seconds were given to each of five areas then four more seconds to the entire sheet. That made the areas from right to left to be 6, 8, 10, 12, 14. I can see the 6 and the 8 and sometimes the 10 second areas but no more. When I held up the 4×5 backwards to the light I could see the differences between the first two areas. Scanning the strips like this really shows the changes.



Another strip was made in single seconds to narrow the changes. f22 @ 1-5 +4 seconds overall. 5-9 seconds as shown. Under a lamp I can see all these steps clearly. Of course the blacks in reality go very black but in the scan the differences are pronounced. That helps to determine what is maximum black.

A 4×5 was exposed to light without a negative in the carrier. The idea was to expose the paper and make as black a black as the paper could make. There is no point in showing it here as it only looks gray. A white sheet was also made. The blacks in the tests looks like it. f11 was used for one minuet; it was developed three minuets as were all other tests. The white was only fixed.

The maximum black 4×5 was held up along side of a 9 second exposure 4×5 and my wife correctly chose the darker one. 9 seconds is not dark enough.

10 or 11 seconds is the correct exposure to make maximum black through a blank negative with my stuff.

Any other negative that has any density at all will print lighter at the same time and development. The first one that I can see clearly will be the correct ASA for that film and paper. That is zone 1.


Tri-X 400 film was used as was Ilford MG IV paper. D-76, stop bath, fixer and Dektol were freshly mixed. Dektol was diluted 1:2, D-76 was 1:1. Development  of paper was 3 minuets.

The New Zone System Manual book supplied these ideas. Not the scanning of the prints. That is my idea.


0 is Black. 10 is White. 5 is Gray. That is according to the Ansel Adams’s book, The Negative.

A light meter, a reflected light meter, will give you exposures to make Gray. A Gray Card will make gray. A black subject will make gray. A white subject will be read to make gray. Two stops more or less is enough to make things look light or dark but more may be needed to make white or black.

The Pentax 6×7 camera and lenses have f8 in the middle of the aperture range. Most lenses go up to f22 and some down to f2.8. That is 3 stops on either side of the middle. If the shutter speed is kept the same that is the entire range which is less than the zones of Adams. The shutter speed is changed one way or the other to yield 4 stops on either side of f8.

Clear negatives make Black. Solid black negatives make White. Photographic paper is White.

3 minuets is the maximum development time. 3/4 to 3 min is the range for Dektol diluted as per instructions. It is diluted more than 1:1. One gallon is mixed at a time. Only so much developer will do so many 8×10 sheets.

A slight gray tone on a negative darker than the clear film base plus fog will produce a slightly lighter black print. You should be able to see both differences, that of the light gray negative and that of a lighter black print. That is Zone 1.

Black on a negative that is not really solid black will produce a very light gray print that is Zone 9. Both should be able to be seen. Enlarger exposure and development times will need to be adjusted to print Zone 9.

Zone 1 and Zone 9 do not need to be on a print at the same time. They do not show detail but they do show up.

A test for the black of Zone 1 is made first. It is in the appendix of The Negative book. FP4 is rated at 125 asa. One exposes at that setting minus 4 stops to get Zone 1. Then the ASA is moved one notch and another exposure is made, centering the needle of the TTL meter as best as you can. 3 exposures or 1 full ASA number is exposed on either side of 125. That would be down to 50 and up to 200. One of those black prints, one of those almost clear negatives, will be the correct one to choose. A densitometer is used to pick one. That will be the ASA to use for FP4. Or you can just pick one that you like. The Pentax lenses only have 1/2 stop increments so do the best you can to center the needle of the TTL meter. Keep records like on the chart in The Negative book.

After that test is made, another one is to be done. It is near the front of the book. A gray reading is made of a textured subject. 4 more and 4 less exposures are made on either side of it. The gray exposure is printed to be gray. Every other negative is printed just as the gray one was.

Grass is darker than #5 gray but can be exposed to match a Gray Card. Let the print tests dry and view them outside compared to a Gray Card. Grass will give you texture in each picture and then you will see when it disappears in the prints.

Long exposures will bring up shadow tones as will long development. But light areas on a print will get lighter faster. There is a reciprocity chart available from a YouTube video I got to be used for Tri-X and very long exposures that increase contrast. Look for The Photographer Academy by Richard White and his Composition and Visualising the Image video. OZ spelling.

Development is set at 3 minuets according to the Zone System Manual book. Exposure then must be adjusted in the enlarger so that the light areas in a print show something and so the dark areas in a print show something.