Retro Reflective Versus Reflective – Online Store
The word “retro” is the key to understanding the difference between a reflective surface like a mirror, and a retro reflective surface like a bike or automobile reflector. Retro means to go back or backward. In the reflective tape industry it means to return light back where it came from and no where else.
A mirror is reflective but not retro reflective because it sends light in different directions depending on the entrance angle. If light was a tennis ball it would be like throwing the ball at a wall at an angle. The ball would hit the wall and ricochet at an angle very similar to the one that it arrived on only the other direction. Now imagine a wall that curved around you so that when you threw a tennis ball at it the ball would always return to you. That would be called retro reflective. The diagram below illustrates this.
How a retro reflective surface works is a matter of geometry. Glass bead retro reflective surfaces use glass spheres to collect light and bounce it back to the source. The rounded shape of the beads is what creates the retro reflectivity. Prismatic surfaces do the same thing but with sharp angles like prisms. They work like the glass beads but are more efficient thus creating a brighter return of light.