The parts to make the 64-to-4 analogue multiplexer arrived this afternoon so I immediately put them together. It is not quite finished yet as I have to parallel up the control inputs to the all the boards. Still, it looks OK. I just hope it works. I now have enough LDRs to make the camera, but I do not yet have the stripboard I need to make the array as regular as possible. These stripboards should come in a couple of days so I will have time to test out the analogue multiplexer.