Roy Lewallen wrote:
I'm not sure why PNP was favored in the
early days, whether due to some basic physics reason or some more
practical processing or production considerations.

I always had the distinct impression it was processing/production
considerations.

--
Frank Abagnale on "Rathergate" (the CBS forgery scandal):
"If my forgeries looked as bad as the CBS documents, [the movie "Catch Me If
You Can"] would have been 'Catch Me In Two Days'."