Ansel Adams developed the Zone System as a tool to help film photographers adjust the tonality and dynamics “seen” by the camera (and envisioned by the photographer) to the “light-space” of the finished photograph. By adjusting the negative’s exposure and development time, he could compress or expand the dynamic range of the scene to “fit” the final photograph.
“I believe the electronic image will be the next major advance. Such systems will have their own inherent and inescapable structural characteristics, and the artist and functional practitioner will again strive to comprehend and control them.” ~ Ansel Adams
I omitted many details in that summary, but what’s important is that serious preplanning was necessary, and that finer computational details of Adams’ Zone System aren’t for the faint-of-heart. Couple this with the fact that you can’t develop a negative twice. If you get it wrong, hope you have a spare to work on!
The digital difference
In digital photography – there is no negative, so there is no development stage. This doesn’t mean that pre-visualization is unimportant. But there are some important differences.
With film, the general rule was “expose for the shadows, develop for the highlights.” Put another way, expose to allow the shadow areas to retain detail, and then alter development time (shorter for a high-contrast image, longer for a low-contrast image.)
For digital, the general rule changes to “expose to the right” – eyeball the histogram and use as high an exposure as possible without blowing out important highlights. Doing this, you maximize the exposure given the shadow areas to help them carry detail and avoid noise.
In a low-contrast scene, this will have a tendence to peg shadow areas of the image to gray
In digital photography one can tame a scene with a high dynamic range (HDR) by combining two or more exposures shot at different exposures into one. HDR photography can be very effective despite the undeserved bad reputation it has garnered due to garish images produced by early immature software and bad artistry.
What would Ansel do?
It’s a safe bet to say Adams would have been thrilled to use digital luminosity masks as a tool to enhance tonality. Lightroom has added a basic, if somewhat limited tool to do this, often enabling a photographer to skip a messy step of taking the image to Photoshop. (to be continued)