9. The Algorithms of Digital Imaging: Blending Modes

Now that you have learned how to use layers in a digital image compositing pipeline, in this chapter, we’ll dive in deeper and take a look at the blending mode functionality contained within each of these layers. These blending modes are present in both GIMP and Photoshop, and they allow algorithmic functions for combining pixels across different layers. These blending algorithms were originally the work of Thomas Porter and Tom Duff, and in the Android API, blending modes are, in fact, a part of a PorterDuff class, named after these two men.