The Zone System and Digital Printing

Ansel Adams developed the Zone System for darkroom photography. Here is a clever digital conversion.

0 > 0
1 > 25
2 > 51
3 > 77
4 > 102
5 > 128
6 > 153
7 > 179
8 > 204
9 > 230
10 > 255

source: Photoshop 6 Artistry - Barry Haynes p.118-123