Post by Steaphany on Jun 27, 2013 14:01:22 GMT
If you can not find a documented development time for the film and developer combination you want to work with, you'll just need to do some experiments.
Adapted from "The DARKROOM COOKBOOK" Third Edition by Steve Anchell:
Development Time
For commercial formulas, development time versus temperature data is readily available from formulator's documentation. Even with commercial formulas, you need to be aware that development times are only approximations or guide lines and may need to be adjusted for your processing methods, nothing is absolute. In some situations you may find a range of development times usually based on a film speed between 100 and 320. To choose a base, approximate starting time:
Suppose a developing formula recommends using between 10 and 14 minutes. With an ISO 125 film, start by developing a test roll for 12 minutes. With an ISO 50 film, develop for 25% less, or 9 minutes. With an ISO 400 film, increase by 25% to 15 minutes.
For a more accurate determination of the development time, you need to shoot a test roll. Include scenes with textured whites and some deep shadows, and a range of details and mid tones. Since film does not preserve EXIF data, keep careful notes. In the darkroom, cut the test roll into four or five approximately equal strips. ( I know, this is being done in complete darkness ) Develop each strip for a different time. Give at least a 10% increase or decrease in time from your starting time determined above and round the time off to the nearest 30 seconds.
EXAMPLE:
An ISO 125 film with an initial development time guessed at 12 minutes needs a test strip processed at 9.5 minutes, 11 minutes, 12 minutes, 13 minutes, and 14.5 minutes.
Evaluate each test strip to determine which development time best suites your situation.
Adapted from "The DARKROOM COOKBOOK" Third Edition by Steve Anchell:
Development Time
For commercial formulas, development time versus temperature data is readily available from formulator's documentation. Even with commercial formulas, you need to be aware that development times are only approximations or guide lines and may need to be adjusted for your processing methods, nothing is absolute. In some situations you may find a range of development times usually based on a film speed between 100 and 320. To choose a base, approximate starting time:
- For films shot at ISO 100 and 320, use a time in the middle
- For films shot at ISO 80 and slower, decrease the development time from
the midpoint by 25% - For films shot at ISO 320 and faster, increase the time from the midpoint
by 25%
Suppose a developing formula recommends using between 10 and 14 minutes. With an ISO 125 film, start by developing a test roll for 12 minutes. With an ISO 50 film, develop for 25% less, or 9 minutes. With an ISO 400 film, increase by 25% to 15 minutes.
For a more accurate determination of the development time, you need to shoot a test roll. Include scenes with textured whites and some deep shadows, and a range of details and mid tones. Since film does not preserve EXIF data, keep careful notes. In the darkroom, cut the test roll into four or five approximately equal strips. ( I know, this is being done in complete darkness ) Develop each strip for a different time. Give at least a 10% increase or decrease in time from your starting time determined above and round the time off to the nearest 30 seconds.
EXAMPLE:
An ISO 125 film with an initial development time guessed at 12 minutes needs a test strip processed at 9.5 minutes, 11 minutes, 12 minutes, 13 minutes, and 14.5 minutes.
Evaluate each test strip to determine which development time best suites your situation.