What's Black and what's White?

As some of you know, I recently bought myself the gift of an old 4x5 film camera, and in order to refresh my knowledge and to rejuvenate my enthusiasm I went back to basics.  I'm still there of course but wanted to share a couple of things I relearned. One of the many places I chose to look was to the writings of Ansel Adams, in this scenario, his book The Camera.

As I rejuvenate my knowledge of the Zone System, I'm reminded of the reality of black and white.  i don't mean film or as colours but as representation of tone.  I'm bridging the world of film to the world of digital and there is a clear parallel here.  In the Zone System, Zone V is what we think of as the mid tone, basically 18% grey.  Zone 0 is black.  And in this case, this means there is nothing there.  It's just like an RGB rating of 0,0,0.  In digital we can and should leverage the ability to manipulate exposure in post processing, which is analogous to push or pull processing with film negatives.  The challenge is that if the histogram for the image in review is up against the left border, and we drag the histogram to the right, we aren't recovering anything, because there's nothing there to recover.   Similarly if we pull the histogram to the left and it starts touching the right border, we aren't reducing the highlights on anything because there is nothing there to see.

In film, black and white define the presence of no emulsion at all on the negative (black) to no removal of silver at all (white).  Adams noted that because we see more "zones" than our cameras / film can that the full range of zones should not be used when thinking about exposure.  He also proposes not to put a lot of investment in Zone I or Zone VIIII because of the limitations in rendering this wide a range.  This makes a great deal of sense in digital as well since our best sensors can only see 6.5 stops.  If we agree with Adams' premise, we make the decision not to be dependent on the full ten stop range of zones, leaving out pure black and pure white and avoiding expectations of content in Zone I and Zone VIIII, then we are really only depending on a six stop range and we have a very solid opportunity to maximize our tonal range.

When we do this, now we have the choice to push or pull our histogram without starting on one of the sides, meaning that there is content that we can make darker or lighter for some level before it drops out or blows out.

Why does this matter?  When we see an image, prior to capturing it, we make decisions as  to where the midpoint in the range should be, because some times what we want at the midpoint is not what is actually 18% grey.  If we maximize the mapping of exposure zones in our image collection, we leave ourselves more latitude in the digital darkroom, which is very much like how Adams and the masters of film used the Zone System to give themselves more latitude in the chemical darkroom.

In the end our point and fire metering gives us pretty good images the majority of the time, but what if we could actually do more at the time of capture to improve our post processing experiences?  Think about it, because we can.