zone system in practice
Over several years of teaching this material I have gradually refined this exposure calibration system to the point where, if it is followed meticuloulsly, a useful and posititve result is the outcome.
This series of three tests results in integrating the three major variables in B/W practice:
Please note: I do not object to this material being used in teaching but would apprecciate a request for permission to use and expect that acknowledgement be given as to the source of this material.
Part one: Establishing a personalized I.S.O. rating
You require a 35mm S.L.R.camera with manual control, a 20 exposure roll of medium speed film, one or two Kodak 18% grey cards and a tripod.
1. Adjust film speed dial to manufacturers recommended I.S.O. speed 100 or 125 I.S.O. in this case! Having done this, take 2 blank frames (i.e. camera shutter set at it's fastest speed, aperture at it's smallest opening and lens cap over the lens).
Take meter reading of evenly lit 18% grey card which is placed close
enough to your tripod mounted camera that it fills the entire frame
when in focus (if you pin the grey-card on a vertical surface, make
sure that you don't have any lighting variation between the top and
bottom or from left to right. I recommend a copystand with four identical
lights as the ideal set-up for this test! If your camera fails to
focus close enough to fill the whole viewfinder with the grey-card,
simply put another card next to it to create a larger field.
3. Hold a piece of paper over the grey card which states your name (if you do this as a group project) as well as the film type, film speed dial setting, aperture and shutter setting as recommended by your light meter. It would be a good idea to make up a card which features all the necessary information in a 'dial style' display. (i.e. 3 circular dials where you merely change the position of a pointer each time you change apperture, shutterspeed or I.S.O. ). Now take a photo!
4. Focus lens at infinity and remove piece of paper from grey card.
Stop lens down to f16
6. Take one photograph of the out of focus 18% Grey Card.
7. Adjust film speed dial to 50 I.S.O.
8. Repeat stages 2 to 6.
9. Adjust film speed dial to 64 I.S.O.
10. Repeat stages 2 to 6.
11. Adjust film speed dial to 80 I.S.O.
12. Repeat stages 2 to 6.
13. Adjust film speed dial to 160 I.S.O.
14. Repeat stages 2 to 6.
15. Adjust film speed dial to 200 I.S.O.
16. Repeat stages 2 to 6.
17. Adjust film speed dial to 320 I.S.O.
18. Repeat stages 2 to 6.
19. Adjust film speed dial to 400 I.S.O.
20. Repeat stages 2 to 6.
You should be up to frame 18 now !
21. Take 2 more blank frames as described in stage 1.
22. Select a developer (must be freshly mixed) and dilute as recommended by manufacturer for this film type and normal exposure contrast. Record developer & dilution ratio.
23. Process film with the greatest care as to (a.) time, (b.) temperature and (c.) agitation technique. (this means that every person must individually process their film and have only one film in the tank). Record a. b. and c. below developer type and dilution ratio.
24. Assess processed and dry film on a light table to find a frame which shows the first definite density greater than the unexposed (clear) frames at the beginning and end of your film.
25. The frame immediately prior to this one will feature one of your I.S.O. settings recorded.
26. Record this I.S.O. rating, it's yours and it is the personal film speed for the camera /lens /film/developer combination you have now established.
If You change to another camera or lens or use different film or developer,
repeat stages 1 to 25, as the rating established in stage 26 no longer
Part two: Normal printing time test (minimum time - maximum black).
1 Set enlarger height to the distance required to print a normal 20
x 25 cm image from your negative and focus the enlarger using a negative
with some pictorial content .
7 Process paper as normal and dry the print.
8 In daylight, assess the print and establish the first noticeable
reduction from maximum black. The step next to this will be the shortest
time for maximum black.
This now becomes your standard exposure time every time you use the enlarger at the height setting used for this test.
Remember, the inverse square law dictates that a 40 x 50 cm projection
requires 4 times as much light as a 20 x 25 cm projection ! This means
that every adjustment to the enlarger height will affect your exposure
in a reciprocal manner.
Part three: Normal development time test.
1. Set camera to personal exposure index ( naturally this only works
if you are using the same film as you did for part one).
7. Adjust shutterspeed to 1/500 th. of a second and take a photo.
will be a zone 2 negative.
8. Adjust shutterspeed to 1/250 th. of a second and take a photo.
will be a zone 3 negative.
9. Adjust shutterspeed to 1/125 th. of a second and take a photo.
will be a zone 4 negative.
10. Adjust shutterspeed to 1/60 th. of a second and take a photo.
will be a zone 5 negative and should print 18% grey!
11. Adjust shutterspeed to 1/30 th. of a second and take a photo.
will be a zone 6 negative.
12. Adjust shutterspeed to 1/15 th. of a second and take a photo.
will be a zone 7 negative.
13. Adjust shutterspeed to 1/8 th. of a second and take a photo.
will be a zone 8 negative.
14. Adjust shutterspeed to 1/4 th. of a second and take a photo.
will be a zone 9 negative.
15. Process this film after using the remaining frames on subjects
of your choice. interesting visual textures.
16. Print your zone 8 negative to the time established in test #2
17. Assess print : is the white slightly greyer than the white on
the part of your print that was under the easel mask?
18. If yes, be happy.
no, because it's too light, repeat steps 1 to 14, adjust your processing
time to be 20 % less than your initial test's processing time .
no, because it's too dark, repeat steps 1 to 14 , adjust your processing
time to be 20 % more than your initial test's processing time.
19. Repeat steps 16 to 18.
If you have problems or if you want to use this system in your teaching contact me: email@example.com
Ansel The Negative
Minor The Zone System Manual
John 'The Zone System Experience' in Australian Photography, December