"Francis A. Miniter" wrote

At this point, you need to prepare a chart ...

.... such as the paper speed charts available at
http://www.darkroomautomation.com/support/index.htm

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.darkroomautomation.com/da-main.htm
n o lindan at ix dot netcom dot com