When I bought my TWR it came with a strange sliding rollfilm back, I think for taking mugshots. At the time there was no info on the net about what I should have down there for 5x4, so I fabricated something out of cardboard as a template. Fortunately I knew someone who could get aluminium lasercut and I had the plate made that slides into the slot. This cut plate, aluminium block and second plate, a couple of bolts, some felt as a light-trap, neoprene foam as a tensioner and I have good grafmatic holder.
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