F-stop test-strip card · Free · No account
F-stop test strip times, worked out and printed in large type.
Type a base time and a stop step, and this card lists the total time for each strip and the seconds to add at each step. A dodge and burn mode gives the total and the extra seconds for any fraction of a stop. The card prints as a free PDF.
- A4 and US Letter
- Prints at actual size
- Goes with The Darkroom Print Record
- Type the base timeEnter the time for the first strip in seconds, such as 8, and choose a step of 1/6, 1/4, 1/3, 1/2 or 1 stop.
- Choose strips or adjustmentsPick 3 to 12 test strips, or switch to dodge and burn and type an adjustment such as +1/2 or -1/3 stop.
- Print the cardDownload the PDF on A4 or US Letter. Totals print in large type, with a strip guide to cut out and the exposure sequence.
Make your card
The page beside the form changes as you type. The PDF is made in your browser and is sized for A4 or US Letter.
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File details
- What it works out
- It calculates f-stop exposure times from the base time and stop step you enter.
- Using the result
- Set the base time from a test with your enlarger, paper, filter and developer.
- Calculation
- Each time is the base time multiplied by 2 to the power of the stops, the usual f-stop printing sum.
- A guide
- The printed times are a guide to test from; your test print decides the final time.
Questions
How are the test strip times worked out?
Each strip’s total is the base time multiplied by 2 to the power of its stops. From 8 s in 1/3 stop steps the totals are 8.0, 10.1, 12.7 and 16.0 seconds.
Are the times exact?
They are rounded: strip times to 0.1 s and dodge and burn times to 0.01 s. Check the exposure on your paper with your enlarger, filter and developer.
What are the additions for?
If you uncover or cover strips one after another, each strip gets the earlier exposures too. The Add column gives only the extra seconds for the next step.
How does the dodge and burn mode work?
Burning +1/2 stop from 16 s gives 22.63 s in total, so 6.63 s extra after the main exposure. A minus value gives the seconds to dodge during it.
Should I print the card at actual size?
Yes. Choose 100% or Actual size in the print window so the type prints at its full size. The card fits one page of A4 or US Letter.
Related Due Form edition
The Darkroom Print Record
Record the tests, exposures, local adjustments and dry assessment behind a black-and-white enlarger print.
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