Breadth

Some years ago I was reading Henry Peach Robinson's book Pictorial Effect in Photography (a text from the 1860s) and ran across a compositional device he termed "breadth" under the discussion of chiaroscuro. I hadn't seen this term before and spent some time with his rather confusing description of it.
The general idea, as nearly as I can tell, is this: while a photograph is a collection of various tones which delineate the various objects in the frame, there is also a larger sense of overall tone to be considered.
Ansel Adams spent a great deal of time banging on about a complete range of tonal values, from rich blacks to white whites, and this has been largely taken as gospel. You can still find, without difficulty, people who will judge any photograph that lacks strong blacks or strong whites as flawed, irretrievably damaged. But in no reference newer than Robinson's book have I found any specific discussion of how tone "in the large" ought to be distributed.
The answer Robinso...