Negative Kammatograph disc

305mm negative glass kammatograph disc with spirally arranged sequence of negative frames of child, c. 1900.

The Kammatograph camera used a 12 inch (30.5cm) circular glass plate to record 350 or 500 images as the plate rotated intermittently.

It was inveted by Leonard Ulrich Kamm in England, patented in 1898 and available from 1900. To record images, the lens cap was removed and the disc was rotated in front of the lens by hand. The disc was removed from the camera in a dark room and processed to produce a negative also on a circular glass plate. This could then be used in the camera to show the pictures, after changing the shutter and lens stop