I'm always finding amazing little things on Erwin Puts web site. This is one of those.
"My first results with the new Spur DSX32-64 developer and Copex microfilm are very promising. The useable sensitivity of the film is EI 50, where you get excellent densities over a range of ten stops. The curve looks quite normal and brings a good CI value. This is a much improved result compared with previous attempts to introduce the Gevaert Copex film into pictorial photography. I would prefer ISO32 as exposure index, but that is a matter of taste.
Resolution is outstandingly good with 140 lp/mm, twice what you get with the M8 and the current crop of digital top SLR cameras."
I await to see his results.