Philip writes ... > *From my observations if you just scan with the WP at 0.1 > as default, you can compress the tonal values rather than > making sure the image ocupies the full range available. > If your image allows a WP of say 0.4 just before clipping > then the available range isn't wasted in the 0-0.4 area* > ...
That's my impression as well. For example, any given photo depending exposure and subject, the scan may be asked to include "white without detail" into the histogram ... which may sacrifice levels for "white with detail". I believe as you force the histogram to include the former and play with the Wp=0-.4 region, you'll notice significant effect on brightness (or apparent gamma). Once you set Wp so as to exclude most "white w/o detail" you'll see less effect ... and it is here where you should probably set the Wp. A good histogram presentation, which might display a "small bump" due to specular highlights would be beneficial, and reduce time wasted at guessing. shAf :o)