Film & darkroom
How to make and read a darkroom exposure test strip
Compare exposures in a useful part of the photograph.
A test strip is a small experiment on the actual paper under the actual enlarger. It should help choose the next exposure, rather than provide a row of random grey bands. Keep the paper-processing conditions stable throughout the comparison.
What the test changes
ILFORD’s exposure-testing guide describes a test strip made by giving different parts of photographic paper different exposures. Place the test where it can answer the image question you care about. One area of a negative may not represent the important shadows and highlights elsewhere.
Evidence: Manufacturer guidance
Write the exposure map
In our worksheet, sketch the bands and write the total exposure each one receives. With a progressive masking method, additional exposures accumulate: a band uncovered twice receives both intervals. Label the dry result so a later viewing does not require guessing the order. Choose a promising exposure, then test the whole image.
Control the comparison
Keep image size, aperture, filtration, paper batch and processing constant during the series. If none of the bands gives a useful result, make a new range rather than trying to salvage the answer from a barely relevant band. A test strip narrows the next decision; it does not eliminate the need to judge a full print.
Sources & further reading
Sources for the specific facts and product descriptions above. Our worked examples, interpretations and practical suggestions are original editorial guidance.
- ILFORD PHOTO — exposure testingManufacturer guidance