dcpixelthis

Here is a video for using layers and adjustment layers to make density adjustments to your imagery.

Using Blending modes Notes:

If you want to make a image lighter:

After the image is opened, copy the background layer by dragging the background layer onto the the new layer button in he layers pallet.

Change the blending mode of the new layer to to screen.  Now the image is about 100% brighter in exposure.  If it is too bright, simply change the opacity of the layer through the opacity slider on the layers pallet until it looks correct.

The same process is can be used to make something darker.  Instead of Screen as the blending mode, use Multiply instead.

Dodging and burning with with Softlight Layer

After your image is opened,  create a new layer with the new layer button.  Change the blending mode of the new layer to Softlight.   Now using just the brush with either White to dodge exposure or Black to burn exposure paint over the areas you want to dodge and burn.  If you want to take away some the adjustments, use the eraser tool instead of painting with the opposite color.  It makes for better adjustment.