There may be times when you want to apply different conversion methods to different parts of the image. Here’s how.
UPDATE: This tutorial uses some obsolete methods such as the hue/saturation method. I created this example about ten years ago, before Photoshop CS3 introduced black and white filters. If I were to redo this today I would use different conversion methods. However this tutorial, along with Selective Color, is a good example of how to use color selection during black and white processing. – DK