Dynamic Range in Film Photography
A Complete Guide to Your Film’s Defining Characteristic
14 min read by Dmitri.Published on . Updated on .
Understanding your film’s dynamic range can help improve the quality of your photography. Measured in stops or lux-seconds, your film’s DR can inform your camera settings and scene selection for optimal contrast and detail levels. Conversely, DR can guide your selection of a film stock for your scene for optimal contrast and detail in the final product. In this guide: What is dynamic range? A definition. Visualizing dynamic range — through the limitations of our eyes. The role of dynamic range in film photography. Dynamic range and film characteristic curves. How to read film characteristic curves. How to select film stock based on its dynamic range. What about exposure latitude? About film density. About image contrast. Rule of thumb. Support this blog & get premium features with GOLD memberships!
What is dynamic range? A definition.
Dynamic range is a range of intensities that a medium can record. It can be measured in decibels (for sound) but in photography, it’s measured in stops or lux-seconds.
The limits of your film’s (or digital sensor’s) dynamic range can be observed in the darkest and brightest spots of photographs depicting a high-contrast scene.
Dynamic range is also sometimes referred to as tonal range. Here’s a tool for converting stops to lux-seconds and back.
Visualizing dynamic range — through the limitations of our eyes.
Have you ever looked towards the bright light and noticed that people and objects in front of it appear very dark?
Thanks to our pupillary light reflex, our irises constrict in response to bright light so that we can see better. We can adjust to changes, but can’t see well in both dark and bright light simultaneously (which is why the people/objects in front of bright light appear dark, even though you could see them well if they weren’t backlit).
This limitation of human vision (needing to adjust) is due to our eyes’ finite dynamic range. Our retinas have a limited range of light intensities they can perceive at once — beyond which everything appears either pure white or pitch black.
This range could be adjusted (shifted) with the help of the pupil that acts as an aperture (plus a few other tricks). But the range itself is relatively constant.
Photographic film has the same limitation: beyond a certain range of light intensities, it will render everything pure white or pitch black. Our cameras let us shift this range to work in brighter or darker scenes with the help of apertures, shutter speeds, and lens filters. Though shiftable, the range itself remains constant and can only be altered with your emulsion choice and the way you develop it.
The role of dynamic range in film photography.
In Figure 1, above, the dynamic range of a hypothetical negative film is illustrated as a range of perceivable brightness between the sunny snow scene (second from the left) and the scene under a tree’s shade. This range is measured in stops, which is a light volume unit.