Digital BW, The Print

At 07:40 PM 1/11/2005 +0000, you wrote:
>paul,
>
>you commented in an earlier message that the zone system is obsolete now 
>that we have
>histograms. you are right when the procedure you describe here works. but 
>in many cases,
>the dynamic range of the scene extends beyond the dynamic range that can 
>be recorded.
>in that case, information at one end of the dynamic range must be 
>sacrificed. my
>understanding of the zone system is that it addresses exactly this issue: 
>not how to get
>the whole dynamic range on paper, but rather how to select the exposure to 
>'focus' on the
>part of the image you care about. what ansel adams showed us was how to 
>make that
>selection reliably. a histogram alone won't help you do this: at the very 
>least you need a
>spot meter to determine the luminance of particular points in the scene.
>
>/daniel

Hi Daniel,

Exposure is part of that process but development is key as well.  Using the 
Zone system, as you likely know, one can contract or expand contrast by 
controlling developing time (or dilution, or type of developer, etc.).  So 
compressing and expanding dynamic range as it appeared on the processed 
negative was indeed one possible outcome of using the Zone System and Ansel 
Adams discussed this at length in "The Negative".  The closest thing we 
have to contracted development comes in RAW file processing.  RAW 
processing can sometimes regain a stop or so of detail but not much 
more.  So if, for example, the highlights are over-exposed in a digital 
file, there's little one can do to retrieve detail.  With sheet film, one 
could have tagged one side of the film holder to show that that sheet of 
film should get less development (N-1, etc.)  Increasing contrast, of 
course, can be done all kinds of ways with digital.  You're right that a 
spot meter can help one make more precise exposure decisions when the 
contrast range of the scene exceeds that of the camera (which is almost all 
the time outside on a sunny day).

That said, I don't use a spot meter any more.  I prefer to use the 
histogram and lower contrast lenses to compress the dynamic range of the 
light going to the sensor.  (as I discussed in this review: 
http://www.luminous-landscape.com/reviews/lenses/rd-1-lens.shtml)  In 
effect, I'm applying the equivalent (in film terms) of increased exposure 
and N-1 or N-2 development via the lens choice.

Cheers,

Sean