I’m fascinated by these cameras. They are an entire photo studio in a box. The photographer uses a hood on the back of the camera to compose and focus and image on the ground glass inside the large box. Once the image is set, the camera is made light tight and the film ( photographic printing paper) is placed on the focal plane. An exposure is made and the photographer reaches inside the camera via a light proof sleeve and develops the paper in the chemistry that is contained in the box. the result is a paper negative that can be re-photographed to produce a positive print. So far this is the best collection of these remarkable cameras I’ve ever come across. They are still used in parts of the world where minilabs and digital cameras are rare.