Camera obscura

painter's Camera Obscura in the Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers of 1772

The Camera Obscura (literally, dark or hidden room, form Latin) is a device consisting of a room or box which is enclosed except for a small hole; this means that the room is kept dark but for the light coming in through the hole. This light projects an image of the outside scene onto a wall or screen. An improvement is to mount a lens in the hole. Artists have used camera obscurae as an aid; the projected image can be drawn around to obtain a picture in correct scale and perspective.

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