The "pentaprism housing" (pyramid shape on top of the camera) serves as a viewfinder for framing the picture. Of course, there is no prism inside. There is just a small hole in back and a larger hole in front for framing the scene being photographed.
I used masking tape to seal the outside edges of the camera where there were gaps in the partially-cut, folded cardboard. After a year or so, the tape started coming apart. I should have used glued strips of paper cut from a brown bag instead. That would have been more durable and would have looked better, too, because the paper has a smoother, more even texture when painted.
To make the door for installing the film, I made three full cuts and one partial cut through the cardboard, thus forming a tight-fitting, rectangular hinged flap. To prevent light from leaking through the edges, I glued on a slightly larger, overlapping rectangle of poster board on the outside surface of the flap. I also glued on matching narrow strips of poster board onto the back of the camera along edges. On the inside of the camera, I glued strips of poster board overhanging the opening. I also glued matching narrow strips of poster board on the inside of the door. The door edges are probably light-tight, even in bright sunlight.
A metal film holder is
glued to the inside of the door. I bought a box of these
Kodak metal film holders at a yard sale. They are
designed to allow 4 X 5 sheet film to be installed into
a photographic glass plate holder. To load the camera, I
slipped a sheet of film into the holder as shown below.
Of course, this had to be done in the darkroom.
After closing the door, I locked it in place with the cardboard slide strip shown below.
On the bottom of the case is a long rectangular piece of circuit board with a drilled 1/4-inch hole. The hole is located directly under the center of gravity of the camera. Behind the hole, I glued a hex nut with 1/4-inch threads. This allows the camera to be mounted on any standard tripod. This feature is important because the camera must be held very still during the exposure.
Next: Using the Camera