One of my three Duo Six-20 cameras. This one has a distance scale in meters, an older Compur shutter with a 1/300 top speed and a Tessar f/3.5 lens. The four-element design of the Tessar yields good correction and resolution, but the added lens-air surfaces increase the likelihood of reflective flare in an uncoated lens. The old Compur's top speed is about a stop slow, but the lower speeds are all close to being correct.
I decided to get a lens hood in order to get the best results from the Tessar, but the only ones I found in the right size on line were expensive and located in Europe. The local Camera and Darkroom shop did not have any that would easily fit the Duo Six-20 either, so I settled for a standard Series Five hood. I cut a small strip of black foam and glued it to the inner rim of the hood to provide a good press fit. I also picked up a selenium cell light meter at the same time to replace my old Sekonic which has gotten lazy in its readings.
I shot all of the pictures on this roll at 1/100 with the Tri-X rated at 200 ASA and processed in Ilfosol 3 at 1:14 dilution.