What an Oreo Cookie Can Teach You About Chroma Keying – Part 1 It’s 3:00AM and I’m awake, working away at my desk. My belly rumbles. I run downstairs and raid the kitchen in search of my favorite late night snack, Oreo cookies and a tall glass of milk. Oreos & Keying Q: What do Oreos have in common with keying? A: Layers! Both Oreos and Chroma Keying depend on layering to make them great. Today I’ll show you how to fix a bad key by using a layered approach.