Today I worked on Lynda.com using Photoshop CC 2015 One-on-One: Fundamentals. I am working on Chapter 7 Brightness and Contrast Lesson How Luminance Works. These are channels.RGB stands for Red Green Blue. Here are more screenshots. This is a little icon on the right of the screen. In this Icon it has different options.These options help with the luminance level. I went from this really washed out look. To this very toned looking one. This happened because I went image and selected Auto Contrast. Now the Lesson I’m working on is The three Auto commands.