There are several sources. The most comprehensive might be the series
_History of Photography_. It covers 2,195 monographs, and 100 or so
periodicals. I think the complete run of microfilms was around $25,000 some
years ago when I first looked into it.
It is published by Research Publications, Inc., 12 Lunar Drive, Drawer AB,
Woodbridge, CT, 06525, USA. Tel (203)397-2600
I don't have their catalog at hand but I recall it was way overpriced for a
few xeroxed sheets that showed a very poor compilation. The series could
also have been better organized as some of the monographs were microfilmed
more than once, using slightly different author's names. Also, the series
are not always complete so do expect to run into a missing issue from time
to time (they don't warn you about this, but I do:-))
Despite these shortcomings the series is still an invaluable resource. The
problem is that most researchers don't need to *buy* microfilms. We just
need to borrow them for a little while. Unfortunately, it now seems
impossible to borrow or rent such microfilms. As I keep working on my next
_Encyclopedia_ I am always looking for a source of early French/German
journals on microfilms. If anyone can help, please contact me offlist.
Luis Nadeau
awef6t@mi.net
nadeaul@nbnet.nb.ca
Fredericton, New Brunswick, Canada
http://www.micronet.fr/~deriencg/nadeau.html
http://www.primenet.com/~dbarto/lnadeau.html