Donald;

I agree with your comment, but all things are relative.

Camera speed is a little better than the 2 - 4 hours of exposure in daylight which is what cyanotype needs. If you improve that by 5 stops then you are talking about 7.5 minute exposures rather than 4 hours. This is still a long exposure time. A 5 stop increase is huge with this type of material, and spectral sensitization is still not possible AFAIK, so it is a very limited system.

That was my whole point. It will always seem like you can almost get there from here, but not quite. I worked with light sensitive copper systems for quite a while and got up to about Kodabromide speed with cuprous oxide. Then it just ran out of steam. I could never get exactly what I wanted from it and eventually had to give up. It was very discouraging.

PE