Camera Obscura

Camera Obscura (Latin for "dark room") is an early optical device. It’s basically a dark box or room with a small hole or lens on one side. Light from the outside scene passes through the hole and projects an upside-down image onto the opposite wall. Artists used it as a drawing aid to trace scenes more accurately.

A modern-day projector works on a similar principle but uses lenses, lightbulbs, and digital technology to project images or videos from a screen (like a laptop) onto a wall or screen. Instead of tracing, we now use it to view movies, presentations—or even project reference images for painting.