George's idea about dust is quite promising.  No tape case is entirely
air-tight and, as the micro-environment in the case heats and cools, dust is
pulled into the container.  Many areas have very distinctive soil
characteristics and an analysis of dust/dirt caught in the corners of the
case could possibly lead to a general geographic location (for example: the
red clay that is so prevalent in certain parts of the Southeast).  Of
course, once you analyze the dirt and get a general idea where the tape may
have come from, you might need to do additional work to match up soil
samples for a more precise location.

The manufacturer's codes can also be used to trace where/when the tape was
made and (possibly) where it was initially shipped for sale/distribution.
The difficulty is that the codes may say where it was made and even what
particular production batch it was from but, the codes do not distinguish
between specific tapes.  Unless all the thousands of tapes from a single
manufacturing run went to the same distributor, the codes are unlikely to
give you much more information than time of manufacture and very general
geographic (as in what continent, or what portion of a continent) the tape
was distributed in.

Another possibility is that analog tapes were frequently reused.  If you
peel the existing label off of an older tape (box), you may well find an
older label underneath with information on it concerning a previous usage.
I have seen tapes with as many as 6 or 7 different labels covering each
other up.

Peter Brothers

> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]]On Behalf Of George Brock-Nannestad
> Sent: Sunday, June 19, 2005 9:23 AM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] Discerning where a tape has been stored
> From: Patent Tactics, George Brock-Nannestad
> Melodie Myers wrote
> > My question concerning the tapes is... can you glean specific
> information from
> > an analogue tape that has some age on it, not only an idea of
> when the tape
> > was manufactured, but where it might have been -- I've seen
> several post on
> > mold and other nastiness growing on these tapes on this
> discussion board. i.e.
> > Has someone come across something that is specific to a certain
> region and
> > would only be found with a tape stored in a particular
> environment? Say in the
> > South? I never encountered any of this in my travels with
> analogue tape, but
> > it occurred to me that many of you are not only archivist, but part time
> > research scientist and super sleuths.
> ----- this is really a forensic question and not one likely to be
> answerable
> by a forensic audio specialist. He or she would ask someone else in the
> department. Some kinds of dust are certainly distinguishable - the
> composition of mineral dust may indicate a more or less extensive
> stay in a
> particular location. The dust in a city is much more filled with carbon
> particles (exhaust) than dust in the countryside. Leaded gasoline
> will give a
> different kind of dust that may date the deposit (ban on lead).
> The location
> may have been somewhere in Australia or other places where asbestos of a
> particular composition is mined, or it may be a place where there
> has been a
> desert storm; the dust may be radioactive for that matter. The good thing
> about dust and dust distribution is that it will not change over time,
> whereas a biological trace may change over time. So, the best
> would have been
> if the tape had been played in a dusty atmosphere: particles
> trapped between
> tape layers. Otherwise: if the tape container has been left open for some
> time.
> I expect royalties if any of the above is found in your work. But then I
> expect that all these ideas have been used in C.S.I. anyway.
> Kind regards,
> George