Thanks. I recall that interesting thread. I vaguely recall checking out the links in that thread but don't think I ever really got the exact answer I was looking for, though. I seem to recall all of those references were for blue tinted bulbs, and there is differing information on whether clear is 1 stop of .5 stop brighter than a blue bulb. I also didn't know at that time that Nr. 40 was essentially the same as the Nr. 11 until Dave mentioned it.

This morning I found some other interesting reference materials at www.donsbulbs.com. That site has old sales brochures for all sorts of bulbs, including flashbulbs. Much of the data is expressed in terms of peak lumen rather than GN, but the Kodak Photoguide calculators can handle that type of data. In one brochure I found confirmation of waht I didn't know before: GE/Westinghouse Nr. 11 = Sylvania Press 40 = Photoflux PF38.