I was playing with Cyanotypes tonight and wondered if there was a similar sensitivity graph line as in the silver processes i.e is there a toe and shoulder? This led me to the question : If there is a toe, would flashing work as a means of contrast control?
Quick, check the other cyanotype thread. Short answer -- based on the curve posted there, there are toe and shoulder pretty similar to what I expect from silver halide. Of course, a "flash" on cyano could be most of a minute in direct sun...
I did some flashing on a portrait platinum series I printed last year. in fact I got few shining on the skin and the background was to bright for me . THe flashing help me to get a creamy background and no shine on the face.
To flah the paper I use another UV lamp (I use to print with a vacuum printer and Blacklight) and I put the coated paper at 2 meters from the lamp and expose for 10sec to 1 minute dependig on the effect I am looking for.