On this extremely useful Photoshop tutorial, Jesús Ramirez (from the Photoshop training channel) explains what are blending modes in Photoshop and how to use them effectively.
Ramirez explains the general idea behind blending modes and than moves ahead to demonstrate how each and every one of them (there are 27) works on a real image. Blending is a very powerful way to increase the potential of layers in Photoshop as they takes the colors of one layer and bled them with the other layer. Blending is very different than simply stacking images on top of other and changing the opacity. The blend in is controlled by the specific bled – as you can see in the examples on the video.
We covered different type of blending in the past on a video by Michael Woloszynowicz and another video by Howard Pinsky.
You can find many more Photoshop video tutorials on LensVid’s Photoshop section.