Identification of historical negatives is one of my specialites. I
think, in this case, the notch code (or lack thereof) has little or no
significance. Notch codes in general are of limited use in
identification of the negative base material. Often you will find the
same notch code used for both nitrate and the later acetate base
negatives because the code identified the *emulsion* to photographers
rather than identifying the base type. After looking at over 10,000
negatives, I can pretty well tell the base type by sight, though, to be
sure, I always test when in doubt.
The staining you describe can also be found on acetate materials.
Perhaps you could describe the odor or any other deterioration you may be
finding in the collection. The dates of the paintings will not be useful
unless you know something about the type of documentation (always done
when paintings purchased, etc.). The copy photographs could have been
produced much later.
The surest way to check for nitrate materials is by testing. I will
describe the test in a seperate note after I hear from you. This should
be performed in a fume hood if possible. I have a couple of contacts for
you at the Smithsonian Conservation Dept.
Remember that all acetate films will eventually deteriorate - often
faster than nitrate materials. Just because the material is nitrate is
not a good reason to destroy the original. You should think about
segregated controlled storage and duplication. By the same token,
because the material is acetate (so called safety film), that, by itself,
is not a reason to ignore storage controls and duplication. Again, the
acetate may be in more danger of deterioration than the nitrate. I have
some references if you need them. You can ftp some files from my
directory that will give you some background as well. I can't remember
the exact names now, but one is NARA.acetate.txt or some such, and the
other is Nitrate.safety.txt or something like that. See below my sig.
file for the ftp info.
Let me hear back on your project and the questions I have posed above.
Loren C. Pigniolo | voice/fax: 415/665-1827
Photographic Preservation Specialist | voice: 800/484-9808 x7841
Photographic Preservation Services | i/net: email@example.com
1044 Judah Street #1 San Francisco, CA 94122-2052 | Please call before faxing
Documents on photographic preservation and a list of our services are
available via anonymous ftp to ftp.netcom.com in the directory pub/PPS-info
On Thu, 9 Jun 1994 NMAA.JOHN@ic.si.edu wrote:
> I have a few negatives with an unidentified notch code. Unlike most
codes "notched" into the side of the > negative this one is a
semi-circular cut at the corner of the film; as if the corner were clipped
off with a hole > punch (but larger in diameter). None of the films have
any imprint. > > I am trying to determine if they are on a nitrate base.
The images are of paintings, two of which show dates > of 1928 and 29. A
couple also have some slight staining typical of nitrates, though many
safety negatives in > our collection were stored in contact with nitrates
and will exhibit the same stains. > > If anyone can give me any info on
these I would appreciate it. > > Thanks, > > John Jones > Project
Coordinator > Juley Preservation Project > National Museum of American Art
> Smithsonian Institution > NMAA.JOHN@ic.si.edu