Film Speed Test – No Densitometer Required

This film speed test is suited to sheet film users with diffused enlarger light sources. It can be completed with just 2 sheets of 4x5 film.
Sandwiching a step wedge negative with unexposed film into a double dark film holder for Testing Film Speed
Preparing to shoot a film speed test

Film speed tests are necessary whenever I change films to one I have not used before.

So, when I bought some boxes of Ilford FP4 sheet film to try out, I needed to test for film speed and normal development time.

Finding Correct Film Speed

You set your camera’s meter or hand-held light meter with a film speed setting, usually referred to as an ISO or ASA setting. Ilford FP4 has a box speed of 125 ISO, set by the manufacturers. Finding a correct film speed for your style of photography is essential.

With my landscape photography, I usually need to exercise fine exposure control to preserve shadow detail in the final prints. It has been my experience to halve the manufacturer’s box speed.

Film Development and Contrast Control

Another side of the same problem to maximising shadow detail, is maintaining good textural control in the print’s high values. Unlike the shadows which are affected more by exposure based on ISO, highlights are affected by time in development.

Therefore, finding the correct development time to suit the contrast of your subject matter is crucial.

Use Just 2 Sheets of 4×5 Film

The test I describe here is best suited to sheet film users who print with diffused enlarger light sources. I use step wedges and contact printing in the darkroom. It can be completed with just 2 sheets of 4×5 film.

I wrote this popular article several years ago and have recently re-edited parts of it. It is now available as a convenient downloadable pdf file that you can keep on file or mobile, so it can be referred to easily.

You can help support this website by purchasing the booklet for less than a cup of coffee (AUD$5 ).

Paperbarks Margaret River Australia
Margaret River Paperbarks 18-25-02 Silver Gelatin Print

Since 1989, Alex Bond has published cards, calendars, books, and posters under his imprint Stormlight Publishing. His images showcase the West Australian environment. Bond's handcrafted, silver-gelatin, fibre-based prints are personally made by the author in his darkroom.

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One comment

  1. Nifty!! I did it the hard way 20 years ago when I was practicing the art of 4X5. I have ordered the step wedge sheet and am anxiously waiting for its arrival.

    Beevo (aka Bill V)
    “Cameras are rated in Inches NOT Pixels”

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