For the full series see http://tale2tell.com/premiere-pro-tutorials/

In this tutorial, Andrew shows how to use the Luma Corrector to change the brightness and contrast of your shot without flattening the shot. The temptation is to use the 'Brightness & Contrast' effect in Première Pro which is a very old effect and shouldn't really be used as it tends to squash or reduce the luma range of a shot thus lowing its quality over all. The Luma Corrector is a much more powerful tool and will work with the shot to improve it and increase the luma range giving you much more control