How Did People Make Mirrors Before Glass?

Long before glass, people polished stone and metal until the surface returned a face. — Chapters 0:00 In the Museum, the Wrong Side 1:46 What Water Teaches — and How a Bowl Improves It 3:19 Reflection Is Not Rare — the Surface Must Be Flat in Two Ways 4:52 Obsidian: Glass From a Volcano — Why Dark Stone Can Reflect 6:32 Shaping the Stone — Abrasives Are Cutting Tools 8:02 Metal Offers Another Route — Casting Is Not the Final Surface 9:36 Why Bronze Can Show a Face — Polishing Changes the Color of Metal 11:01 A First-Surface Mirror — and Image Quality Was Different 12:32 The Mirror Needed Maintenance — and the Decorated Back Preserved Identity 14:01 Mirrors Were Expensive Objects — and Not Seeing Yourself Is Not the Same as Having No Identity 15:33 Glass Changes the Job — but Early Glass Was Not Automatically Mirror Glass 16:56 Tin, Mercury, and Thin Silver — and the Face Became Architectural 19:12 The Answer — A Surface Smooth Enough to Keep Light in Order 20:35 After the Answer — Not Necessarily Worse, and Still the Same Geometry 22:05 Final Reframe — A Surface That Remembers Your Face — A new episode every week. This channel takes one ordinary thing and follows it until it stops being ordinary. If you spotted an error, say so in the comments. Corrections get pinned. — Credits Bronze mirror, Eastern Han dynasty (front and back): Freer Gallery of Art, Smithsonian Institution; photos by Gary Todd, CC0, via Wikimedia Commons Ornate Salon with Frescoes, Mirrors, and Natural Light (cropped): Michael Gaylard from Horsham, UK, via Wikimedia Commons, CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · https://commons.wikimedia.org/wiki/File:Ornate_Salon_with_Frescoes,_Mirrors,_and_Natural_Light_(55246910969).jpg Images (cropped): Beautiful mountain reflection (Unsplash) (Johannes Plenio jplenio); Safety mirror with extreme wide angle opposite of garage entrance, having hidden security camera (Pittigrilli); John Dee's mirror British Museum 26