One of the crucial aspects of film photography is the ISO of the roll. While the number is printed on the box, the final results can be entirely different. We have heard of instances where some photographs have been overexposed, or the development process resulted in ruined shots. In fact, photographers have learned to test the film, develop it, and depend on the Zone System to get things right. Understanding these challenges, a veteran film photographer on Reddit has decided to utilize a modern workflow to achieve the correct ISO setting: the ZoneLab. Here is a quick look at what the app can do.
A Tool For Serious Photographers
Created by user Evan Mathis (thrirtyfive), and posted on r/analogcommunity, ZoneLab is a macOS application designed for film photographers to figure out the “true working ISO” of their film and the developer. This is achieved via structured zone testing and sensitometric analysis. Mathis, who has been shooting on film for over 4 decades, states that the inspiration to build the app came from a personal quest:
I wanted to chart and catalog the effective ISO of various combinations of film, developer, camera and lens. So, I started to build an app that could do just that. The deeper I got with it, the more I wondered if this would be useful to other film nerds.
ZoneLab also makes one understand that different developers, agitation methods, temperatures, lenses, and even shutter inaccuracies can further affect the exposure. The app achieves this by zone tests, which are multi-step exposure series of an 18% grey card that is calibrated where the middle grey falls on the resultant negative. While it was designed to cater to film labs, Mathis is considering opening the app to serious analogue photographers.
So, How Does it Work?
The app allows one to add measured film densities, either from their own transmissive densitometer or through readings from a professional lab. It then calculates the following:
- Effective ISO
- Contrast Index (CI)
- Gamma
- Tonal Range
- Exposure Latitude
In addition to the graphs, the app also allows photographers to compare sessions, track developer changes, and see how different processing decisions affect contrast and latitude before committing to them in the field.
In a way, the app reframes the information for photographers to establish a baseline for their favourite film and developer. Additionally, it predicts how changes in processing can affect their image. It is like knowing everything beforehand rather than discovering what can go wrong later.
While this is not ideal for casual photographers, those who treat film as a craft, such as large-format or medium-format photographers, will benefit from ZoneLab. In a way, the app reminds us that film photography’s future may lie not just in nostalgia, but in precision.
The app is still in its alpha stage, which means that the creator will add more features and fine-tune it as the suggestions come in. A beta will be released soon. For more information, head to ZoneLab‘s readme page.
While this is not ideal for casual photographers, those who treat film as a craft, such as large-format or medium-format photographers, will benefit from ZoneLab.