How to Measure the Dynamic Range of Film

In this guide: How manufacturers measure their films’ dynamic range. How to measure your film’s dynamic range and plot film characteristic curves at home.

Understanding the dynamic range of your emulsion can help you make better images¹.

It will inform you how your film will behave in various lighting conditions in a way no sample photo or a description lacking this information can. I base most of my exposure recommendations in my film reviews on dynamic range data, and this guide on making perfect exposures revolves around it too.

Some photographers even rely on dynamic range data to identify the source of the rebranded film stocks. Unfortunately, not all manufacturers list this information, which is a shame as it would’ve helped us make better images¹ with films such as Polaroid, Instax, Film Ferrania P30, and many others.

In this short guide, I will explain how film’s dynamic range is measured by the manufacturer and how you can even estimate the dynamic range at home with simple tools like a sheet of paper and a light source. This is the exact method I used to graph my Polaroid film characteristic curves.

If you aren’t familiar with the concept, I wrote a guide that explains dynamic range in simple terms. TL;DR: dynamic range is a number that describes how much of the shadow and highlight information a particular film can register simultaneously. This single number is taken from a graph of film densities (how dark/light the developed film emulsion is) in response to set light intensities — called film characteristic curves.

If you are still unsure what dynamic range is or how film characteristic curves may be helpful to your photography, this article may help you understand these concepts in practical terms.

¹ — It’s understood that “better” or “best” are subjective terms; however, in this context, they mean getting results you envision with less guesswork and fewer film frames wasted.

How manufacturers measure their films’ dynamic range.

Film negatives look darker when they receive more light and lighter/more transparent when they get less. Film’s dynamic range is the range of brightnesses of the received light between the darkest and the lightest shade the emulsion can produce — which are graphed as characteristic curves (see the illustration below).