The principal of the camera has long been known: light entering a minute hole in the wall of a darkened room forms on the opposite wall an ________________ image of whatever lies outside.
2.
______________________ is basically a way of fixing the camera image by the action of light upon substances sensitive to it.
3.
The incentive to work out a practical technique for creating pictures came from the rising ____________________ of the late 18th century.
4.
The first mechanical device used in the production of pictures was the camera _______________.
5.
Another mechanical device used to create pictures that could more easily be carried about and was widely used by travelers was the camera _____________.
6.
Images captured using these early "cameras" were actually __________ by a person on a sheet of paper.