Hints for Interpreting Film Tests
July 12th, 2008 | Người đăng: chau
Phân loại:
Under development
Special thanks to the ZS mailing list for its feedback during the production of this information
Context
The outline below is a document in progress. It is intended
to help analyze film test results. The first step, is always to
get the film speed nailed down for any target development
(N, N+1, N-2, etc) because film speed does change with
changes in development.While trying to nail down the film speed for a particular development,
other results are generated. With practice, you can glean useful information
about film development from most film tests. Until the film speed
is nailed down, the development information is secondary and unreliable.
Even so, with careful thinking, you can speed the process of testing
film along significantly by reducing the number of tests that
you actually expose and develop.The point remains to produce the best film test feasible, not
to save time. But if you can save a couple of hours, why not.When/How to use this information
The information on this page is useful when you have a film test
that has been exposed, developed and measured for density. The
next thing you must do is determine what the results mean.
The assumptions here are that you are working toward establishing a particular
development for a particular film -- for example N + 1 for Tmax 100.
Also, it is assumed that you know the particulars of the current test -- for
example that you amde a series of exposures (bracketed)
for Zone 1 and Zone 8 at centered around EI 64.Use the outline below to determine your next film test. First
compare the density of Zone 1. It should be between .09 and .12.
If your Zone 1 density is less than .09, you need that section
of the outline. If your Zone 1 density is greater than .12, you need that section
of the outline. If your Zone 1 density is between .09 and .12,
you need that section of the outline.Good luck.
- Zone 1
- < 0.09 (not enough exposure)
- Filmspeed Recommendation
- decrease effective EI and retest
- Important note about speculations on film development
- All of the specualtion below is pure guesswork. It is based on experience analyzing many filmtests.
- Nevertheless nothing is known until a good test is produced and repeated until trustworthy. The very
- best that the speculation below can do is help reduce the number of test iterations. No guarantees
- whatsoever about the usefulness or accuracy of this information.
- Development Analysis based on Target Zone density (typically Zone 7, 8, or 9)
- highlight density below target zone density by a significant amount (> 0.1)
- Film development being tested
- N - 2 ( or greater)
- Highlight density may or may not be affected by lowering filmspeed.
- Since the target zone density is off by a lot, lowering the film speed may (or may not) compensate nicely.
- Recommendation: next test use a little more development time
- N - 1, Normal dev, N + 1
- Highlight density will be affected noticeably by lowering filmspeed.
- Since the target zone density is off by a lot, lowering the film speed may (or may not) compensate nicely.
- Recommendation: next test use the same development time
- N + 2 (or greater)
- Highlight density will be affected noticeably by even slight lowering of filmspeed.
- Since the target zone density is off by a lot, lowering the film speed may (or may not) compensate nicely
- Recommendation: next test use the same development time, using even less developement time might be necessary in the end.
- N - 2 ( or greater)
- Film development being tested
- highlight density below target zone density by a little (< 0.1)
- Film development being tested
- N - 2 ( or greater)
- Highlight density may or may not be affected by lowering filmspeed.
- Since the target zone density is off by a little, lowering the film speed may (or may not) compensate nicely.
- Recommendation: next test use the same development time
- N - 1, Normal dev, N + 1
- Highlight density will be usually affected by lowering filmspeed.
- Since the target zone density is off by a little, lowering the film speed may (or may not) compensate nicely.
- Recommendation: next test use the same development time
- N + 2 (or greater)
- Highlight density will be usually affected by lowering filmspeed.
- Since the target zone density is off by a little, lowering the film speed may compensate nicely or may actually overcompensate.
- Recommendation: next test use the same development time or very slightly less development time.
- N - 2 ( or greater)
- Film development being tested
- highlight density is very close to target zone density (within 0.05)
- This is a somewhat unsatisfying situation. The highlight density is correct
- but the film speed is too high. Adjusting the filmspeed lower will cause a shift in the
- highlight density and therefore, the amount of development will normally have to be adjusted.
- Film development being tested
- N - 2 ( or greater)
- Highlight density may or may not be affected by lowering filmspeed.
- Since the target zone density is about right, lowering the film speed may (or may not) negatively affect the highlight density.
- Recommendation: next test use the same development time or just a 5 to 10 seconds less development time
- N - 1, Normal dev, N + 1
- Highlight density will probably be affected by lowering filmspeed.
- Since the target zone density is about right, lowering the film speed may shift the highlight density a bit too high.
- Recommendation: next test use 5 to 15 seconds less development time
- N + 2 (or greater)
- Highlight density will be affected by lowering filmspeed.
- Since the target zone density is about right, lowering the film speed expect that the highlight density will be too high using this development time and less film speed.
- Recommendation: next test use 15 to 30 seconds less development time
- N - 2 ( or greater)
- highlight density above target zone density by a little (< 0.1)
- In this situation, certain things are clear. The film development is too high.
- Further, the next thing that must be done, lowering the effective filmspeed and retesting,
- will only add density if the same amount of development is given. Therefore, for
- all conditions, development time should be reduced.
- Film development being tested
- N - 2 ( or greater), N - 1, Normal dev, N + 1, N + 2 (or greater)
- reduce the development time by 15 to 45 seconds
- N - 2 ( or greater), N - 1, Normal dev, N + 1, N + 2 (or greater)
- highlight density above target zone density by a significant amount (> 0.1)
- In this situation, certain things are clear. The film development is too high.
- Further, the next thing that must be done, lowering the effective filmspeed and retesting,
- will only add density if the same amount of development is given. Therefore, for
- all conditions, development time should be reduced.
- Film development being tested
- N - 2 ( or greater), N - 1, Normal dev, N + 1, N + 2 (or greater)
- reduce the development time by 15 to 60 seconds
- N - 2 ( or greater), N - 1, Normal dev, N + 1, N + 2 (or greater)
- highlight density below target zone density by a significant amount (> 0.1)
- Filmspeed Recommendation
- >0.09 to < 0.12 (exposure is correct)
- Filmspeed Recommendation
- effective EI is correct for this developer/time/exposure combination
- Development Analysis based on Target Zone density (typically Zone 7, 8, or 9)
- highlight density below target zone density by a significant amount (> 0.1)
- Film development being tested
- N - 2 ( or greater)
- N - 1
- Normal dev
- N + 1
- N + 2 (or greater)
- Film development being tested
- highlight density below target zone density by a little (< 0.1)
- Film development being tested
- N - 2 ( or greater)
- N - 1
- Normal dev
- N + 1
- N + 2 (or greater)
- Film development being tested
- highlight density is very close to target zone density (within 0.05)
- This is a somewhat unsatisfying situation. The highlight density is correct
- but the film speed is too high. Adjusting the filmspeed lower will cause a shift in the
- highlight density and therefore, the amount of development will normally have to be adjusted.
- Film development being tested
- N - 2 ( or greater)
- N - 1
- Normal dev
- N + 1
- N + 2 (or greater)
- highlight density above target zone density by a little (< 0.1)
- In this situation, certain things are clear. The film development is too high.
- Further, the next thing that must be done, lowering the effective filmspeed and retesting,
- will only add density if the same amount of development is given. Therefore, for
- all conditions, development time should be reduced.
- Film development being tested
- N - 2 ( or greater)
- N - 1
- Normal dev
- N + 1
- N + 2 (or greater)
- highlight density above target zone density by a significant amount (> 0.1)
- In this situation, certain things are clear. The film development is too high.
- Further, the next thing that must be done, lowering the effective filmspeed and retesting,
- will only add density if the same amount of development is given. Therefore, for
- all conditions, development time should be reduced.
- Film development being tested
- N - 2 ( or greater)
- N - 1
- Normal dev
- N + 1
- N + 2 (or greater)
- highlight density below target zone density by a significant amount (> 0.1)
- Filmspeed Recommendation
- > 0.12 (too much exposure)
- increase effective EI and retest
- < 0.09 (not enough exposure)
- Is Zone 1 between .09 and .12?
- Yes (Exposure is correct)
- No (Exposure is incorrect)
- Film development being tested
- N - 2 ( or greater)
- N - 1, Normal dev, N + 1
- N + 2 (or greater)