What "calculations" did you apply? Levels? Curves? Brightness/Contrast?

Try this:
1 - Create and Adjustment layer above the base layer of Levels or Curves - your tool of preference.
2 - Create another one above it - Hue/Saturation and slide Sat down to 0 - make it B&W.
3 - Creat a new Layer right above the base image - change the mode to Soft Light.
4 - Hit the letter D to make your colors default B&W.
5 - Get a soft brush and lowe the opacity to 30%.
6 - Paint black over the circled areas - this is dodging and burning without the actual Dodge&Burn tools (which completely bite IMO). Paint sparingly and build up density - this is so you don't make it too dark too quickly.
7 - Aso paint over some of the lighter areas like their faces (and maybe portions of the lighter sides of their clothing as well) - to darken them down a bit as they'll blow out in print.

You don't have to stick with only 1 Soft Light layer - you can have several to build things further - either lighter or darker, or to alter small portions in a mass painted area. Did that make sense?

The reason to go through all of this is so that in making all these changes you're not doing anything to the actual image itself. If you look at what you've done so far, realize you haven't changed the base image YET. This is deliberate - if you later decide you want to change somethig BACK, you now can - if you've changed the base image at all, you can't.

Hope this helps-
-Lew ;-)