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 the 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
alexbond
alexbond

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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3 Comments

  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”

  2. You seem to like the Ilford LC29 developer. For some reason this is hard to find locally and I elected to grab a bottle of the Ilfotec HC due my immediate need and not wanting to wait out a mail order.

    What are your thoughts on this developer? I have read elsewhere that the LC29 is much diluted version of HC and the properties are pretty similar.

    I will likely be doing a mix of roll films and sheet. The roll films believe it or not are from my Pentax 110Auto SLR. LOL

    Have you used the Ilfotec HC and what were your pros and cons?

    • Hi Bill, thanks for a great question. This is exactly why I wrote the PDF downloads about Testing Film Speed, Proper Proofing and Stand Development.

      I get this kind of question about film and developer combinations frequently. Truth is I have never used Ilfotec HC, so short answer: I don’t know! Just looking at Ilford’s technical sheet, its seems it is a highly concentrated developer that must be made into a stock solution first, then diluted to a working solution.

      My advice Bill, would be

    • use the same 4×5 sheet film as the 110 film you wish to develop
    • create several4x5 test-step wedge negatives in camera as described Testing Film Speed
    • process one test-step wedge negatives using your regular developer and processing technique
    • contact print your result with your enlarger
    • from these result determine the development time for normal contrast and check your film exposure index
    • repeat the above step if the first tests require fine tuning (you rarely get the best information on the first test)
    • You should now have a grey scale wedge confirming the optimum development time for normal contrast development for your particular film and regular developer.

      Now to answer your question.

      What are your thoughts on this developer? I have read elsewhere that the LC29 is much diluted version of HC and the properties are pretty similar.

      Using the identical 4×5 test-step wedge negatives you exposed at the start, redo the tests above using your new developer, Ilfotec HC.

      When you are done, compare the visual information side by side on the contact prints. You will have accurate information about the development time for Ilfotec HC, how it may differ from your regular. The tonal spread on the contact sheet may be slightly different too, as may be your effective film speed.

      Using these test procedures, and keeping your methods consistent, you have a real basis from which to make comparisons.

      Again, my procedures involve the use of 4×5 sheet film and step wedges instead of expensive densitometers, and my methods described are based upon using diffused enlarger light sources, although I am sure you could modify it for condenser sources too.

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