Dan - I think these techniques were more valid when everything you did to an image added more contrast and lost more detail, but that's not really true anymore, and especially with both black and white and color negs, with their very extended dynamic range. I mean, with color neg, you can expose for a healthy shadow, be three stops over in the highlights and it'll still be just fine. The trick of course is to make all the tonal areas have the right contrast for how you think the image should look.