What I saw, however, was that the aperture was only closing down to about f8 before the shutter action was complete.
It seemed likely that some congealed lubricant and dirt on the aperture blades was interfering with sequence of events leading to proper exposure. The problem with the Retina Reflex is that you can't get clear access to the shutter without completely disassembling the camera. That is more of a repair job than I was prepared to undertake, however, so I decided to just try to resolve the problem with the application of some judiciously applied electronic contact cleaner which I picked up at a local auto supply store.
It is possible to get limited access to the shutter and aperture blades on the Retina Reflex by just removing the front lens group. I set the shutter to the B setting so I could hold it open and get at the aperture blades underneath. With the aperture set to f22 I shot a couple short squirts of the cleaner onto the aperture blades, and worked the shutter open and closed several times which carried the black scum out onto the surface of the blades. I then scrubbed the blades gently with some cotton q-tips until they looked clean.
I let everything dry thoroughly overnight and cleaned the the lens surfaces. The shutter seemed to be working fine, so I took the camera out the next day loaded with a roll of Kentmere 400 which I shot at 200 ASA for processing in PMK Pyro.
I won't be surprised if I have to perform this operation again some time in the future, but I'm happy for now to be able to use the Retina Reflex again as it is one of my great favorites.
