I hate to say it but..... the old Basic Photography series from Ansel
Adams is dated as hell but it's the best introduction to sensitometry
that you will ever find.
Gamma tells you a little bit about the image scale... it tells you about
the midrange contrast. It doesn't tell you about highlight contrast or
shadow contrast. Only being able to plot the curve and look at its shape
can you do that.
Adams' methods are kind of curious by modern standards but they are greatly
simplified for hand work, and they actually work.
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