(Back to tutorials index)  Photoshop Advanced Blending : `Blend
If`  Some of the most useful features in Photoshop are very well
hidden, you discover them by accident or somebody shows you. One
of the best Photoshop tricks was shown to me by my former
colleague Antti Kallioinen. I`m very grateful he showed me this
trick, because this isn`t something you would stumble on
yourself. The feature in this case is the `Blend If` feature of
the `Layer Blending Options`, it allows you to quickly blend
layers based on luminosity. For this tutorials I assume you have
a basic to advanced understanding of Photoshop, I will use
pictures as much as possible to explain how it works.  Update
1st of February 2008: Jeff Ross has created a short video
tutorial which explains this technique clearly and without the
tedious reading:  (Video tutorial by Jeff Ross: www.custom-
airbrush.com)  Read on if you want the in-depth text version...
The Basics  The `Blend If` options will allow you to blend
layers by the luminosity of the unde