Flash and tinsel are two types of synthetic materials used in fly tying to create shiny and reflective elements that imitate the appearance of fish scales and other natural prey.
Flash materials are thin, shiny synthetic fibers that come in a variety of colors and textures. They are often used to create the tails, wings, and bodies of flies, as well as to add accent and flash to other materials like chenille and dubbing. Flash materials can be tied in as strands or used in small clumps to create a more realistic appearance.
Tinsel, on the other hand, is a thin, metallic material that comes in a variety of colors and widths. It is often used to create ribbing on the bodies of flies, as well as to add flash and sparkle to wing cases and other elements. Tinsel can be tied in as a single strand or wrapped around the hook shank to create a more textured appearance.