Black and White = Gray Scale?

[Garbz]

Having a full tonal range in black and white is a rule. .

That rule has nothing to do with black and white and has everything to do with wanting a contrasty image.

Given the proliferation of cross processed and dull looking instagrammed photos these days I'd say the rule really is don't make a contrasty image ...

 

[Light Guru]

I agree with your premise that a good black and white image should have a pure black, pure white and full spectrum of grays in between if possible. This was the basis for Ansel Adams zone system

No the zone system was created as way of controlling the tones an contrast in the image.

The zone system is more the. Chart that goes from white to black. It also includes metering the screen selecting the zone you want to place your highlights and shadows on. It then goes into the development time of the image. Hence the saying "expose for the highlights develop for the shadows"

It's also important to note the contrast and tonal range are not the same thing. In his book The Art of Photography: An Approach to Personal Expression, Bruce Barnbaum says

"image contrast depends on tonal juxtapositions, not on tonal range.”

He goes on to explain that you don't need big contrast in every image. I high contrast image is going to give a vary different feeling then a low contrast image. Your choice of high or low contrast image should be based on what feeling you want to in those who view the image.

I highly recommend checking out the book "The Art of Photography" by Bruce Barnbaum