The 24 Patch Classic ColorChecker has been in use in photography since 1976 and sometimes I would swear it just came out yesterday because very few professional photographers and retouchers have a clue how to use it and read it. I’ll go over the most popular uses of the ColorChecker in detail below.
The Classic [...]

Creating  depth, better separation, and detail can be accomplished a number of ways.  Most retouchers use multiple curves and other dodge and burn techniques.  But by teaming your curves adjustments with channel mixing you can get a lot more from your images. 
Without a solid tonal structure to begin with, your creating a lot of extra work for yourself. [...]