Pictures and engravings can be easily reproduced by photography. If framed, the glass must be removed, or the reflected light will interfere with the image formed by the lens. The picture must be placed in a good light, and the front of the camera must be parallel with it, or the copy will be distorted. A small stop should be used, and the negative rather underexposed than otherwise. Copies of photographs, except on a reduced scale, are seldom as satisfactory as the original, for the grain of the paper gives a peculiar mottled effect to the picture.