By the late 18th century, small, easily portable box-form units equipped with a simple lens, an internal mirror, and a ground glass screen had become popular among affluent amateurs for making sketches of landscapes and architecture. The camera was pointed at the scene and steadied, a sheet of thin paper was placed on top of the ground glass, then a pencil or pen could be used to trace over the image projected from within. The beautiful but fugitive little light-paintings on the screen inspired several people to seek some way of capturing them more completely and effectively—and automatically—by means of chemistry.