A significant improvement on the double hue / sat adjustment layer trick
from a very cool Photoshop theory site:
Ra togreyscale2 - TechSlop
Provides a good dissection of Russel Brown's double hue / sat adj layer method & trumps it with this:
"My variation on Brown's variation: Leave the HSB Ad-Layer in Normal mode. Use the drop-down and fall-offs to select a range.
Use the L slider to lighten or darken the range. If you want yellows lighter, then make them lighter.
If you want greens darker, then make them darker. No sense in messing around with H and S.
Simple and direct. Extremely controllable and predictable. Even makes use of the entire range selected using the fall-offs. "
Detailed conversion strategy:
Digital Black and White
-Mark