Quoted By:
Here's my setup. Not shown: light mask/film flattener, large diameter cardboard tube to reduce ambient light (even though I shoot at 1/200), flash, and flashlight (RIP).
White parchment paper in 2 layers, and aluminium foil covering all brown surfaces on the inside. Rickety legs and film guides glued on. Film sliding surface covered in electrical tape. Box used is a Honda Odyssey fuel pump box from when they were doing those recalls. Anything similar should work. Shooting my YN560III at 1/8-1/32 and a reversed 50/1.8D at F8-11.