Hi, Katie,
I'm not talking about SCBA type respirators, just the step up from the
dust mask at the Home Depot.
The image of the NYPD officer in the Wikipedia article shows something
close to what I purchased at Home Depot.
http://en.wikipedia.org/wiki/Respirator
I do realize there may be protocols, etc., associated with using these
in the workplace, and I know nothing about that. But, I would much
rather wear one of these than the simple dust mask because the dust
masks never seem to fit well.
Yes, I realize that bad things can infiltrate through the eyes as well,
but I am careful not to rub my eyes.
MARIE: Did you not install the refrigerator in the processing room? I
thought you had done that, too, and named it "Richard" <smile>.
Katie, as to your other questions:
>>if you are reserving seperate equipment for baking moldy tape, are
you also reserving seperate equipment for playing it?
Yes and no. I have a headless mold transport in the garage, but I clean
the tape with a dilute chlorine bleach solution that has not proven
harmful to the tapes, but should be harmful to the mold. The tape is
wiped end to end and placed on a clean(ed) reel.
The tape is then brought into the studio for transfer.
>>Our audio archivist and I have only come across moldy tape once since
we've been doing this ( a few years), and we we're able to make the
decision to de-acession the tape in that instance.
I get some work from large corporations who don't want to make that
decision and also don't want to risk a lawsuit. I am careful. I've done
research. I don't think I'm taking an excess risk. I usually request no
boxes, no paper, and ship them to me in plastic bags.
>>I've been wondering about differentiating between different tape
bases before baking. Acetate and PET - there are a couple of ways that I
know of if it were really in question (using polarized filters, for
one,I think - but if there is an easier way, please let me know) -
In many collections, you CAN rely on the box as your first source of
information. The easiest thing to do is to hold the tape up the a strong
light. If you SEE light coming through the tape pack (the 1/4-inch
dimension) i.e. through the edges of the basefilm, then it is acetate. I
understand this is reversed for film, but if you take some Scotch 111
(very common acetate tape) and hold it up so you're looking at the disc
of the reel, you'll see light coming through.
While this is not 100% accurate, I do know of a few instances where
baking has helped non-back-coated tapes, by and large all tapes that
need to be baked are back-coated.
The worst of the bunch--the Ampex/Quantegy 406/407456/457 tapes were
plentiful AND need baking. These are black backcoat and brown magcoat.
If I get something that looks like this, it is baked as you can do more
damage winding through a tape that needs baking than baking it.
PVC tape is very rare and should not be baked, but I don't know how you
differentiate it from PET.
NOTE: Scotch called their acetate base "Plastic" and often used the
DuPont trademark "Mylar" for their PET based tapes.
For 3M and BASF(etc) there are good lists at:
http://www.aes.org/aeshc/3mtapedoc.html
http://www.aes.org/aeshc/basftapedoc.html
These (and some other useful resources) are listed in the middle of
www.aes.org/aeshc/
I think there is one 3M PVC tape listed. BASF and related companies made
more, including the 1944 I.G.Farben Magnetophonband TypL which was
homogeneous--the mag particles were not coated on, but rather were
embedded in the basefilm.
One other resources is I attempt to keep a current list of degrading
tapes on my website
http://richardhess.com/notes/formats/magnetic-media/magnetic-tapes/analog-audio/degrading-tapes/
Here is a tag sort of my blog articles (accessible in the bottom half of
the sidebar)
http://richardhess.com/notes/category/archive-operations/tape-aging/
This sort also might be of some interest (and has some duplication)
http://richardhess.com/notes/category/archive-operations/archival-practices/
>>but do we need to worry about ruling out PVC as well?
See comments above.
>>I'm certainly not enough of a chemist myself to be able to take the
laundry list of potentially harmful components I recieved and trace it
back to any particular of the makeup of a tape, unfortunately.
Benoit Thiebaut did some research for Prestospace on u-matic video
cassettes and identified four different chemistries for the same
manufacturer/type number. At least some of the problem is attributable
to chemical reactions that did not complete as expected or designed. At
this point, I don't think we'll ever obtain enough information to
reverse engineer all the different tape formulations. There will never
be a pool test kit is the consensus of the chemists I've talked with.
You have read my paper, no?
My paper on tape degradation that was originally presented at the Audio
Engineering Society's 121st convention in October 2006 in San Francisco
was published in the ARSC Journal in the Fall of 2008. It is available here:
http://www.richardhess.com/tape/history/HESS_Tape_Degradation_ARSC_Journal_39-2.pdf
I hope this helps.
Cheers,
Richard
--
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.
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