The illustration in Figure 2 shows how Photoshop can be used to either mimic the effect of a filter in front of a lens or, in playing with different colors, can create a completely unique effect.
Figure 2. Effects of different filter settings in Photoshop when converting to black and white.
Post-Processing Tonal Control
Another freedom from reality in working in black and white is being able to dramatically modify tonal contrasts and densities in a way that seems natural and perfectly reasonable but would look like a big mistake in color. A case in point is with the use of considerable tonal controls to realize my objective with one of my most significant photographs, Bridalveil Fall in Storm, Yosemite 1974.
I was running the darkroom for one of Adams’ Yosemite workshops, and the entire group took a “high country” field trip on a day a fluke thunderstorm rolled through Yosemite. The wind and rain cut the trip short.
Heading back into Yosemite Valley with some fellow assistants, I encountered an amazing view of hanging clouds and Bridalveil Fall. We screeched to a halt and reached for our gear. I set up my 4×5 camera, made two exposures, changed lenses and then made two more exposures. Since my workshop job was running the darkroom, I developed the film the same day and contact proofed it. But the proofs were a bore! They had all the tones but none of my “mood.”