Hello wvmarle
The camera is in the style of a c900 box camera
In the one I'm making the film ( I use bromide paper as a film) is held on sheets of timber with twin-stick tape the holder are loaded in the rear of the camera in a vertical positon held in place with a spring , once expost the holder is released and fall forward and is stacked in a horozantal posirtion.
The exposure time I know the aperature size and the speed of the film, so the exposure time is read with an exposure meter. Colin