Scotch Tape 888

Arsenio Sanchez <arsenio3 [at] santandersupernet__com> writes

>Can somebody give me some information about the tape Scotch
>Conservation and Preservation Tape 888? The maker say that it
>completes the norm ANSI IT9.16.

I hope the following is helpful:

I have seen this tape and the company's brochure.  According to
their product literature, it has passed the ANSI IT9.16 Photographic
Activity Test, also called the PAT (perhaps tested by the Image
Permanence Institute or by their own labs?).  This would not be
unusual as a number of pressure sensitive tape adhesives pass the
PAT. *However*, materials used for the storage of photographs must
*both* 1)  pass the ANSI 9.16 PAT AND 2) meet the requirements of
the ANSI 9.2 Filing Enclosures standard.  In IT9.2 it states that
pressure sensitive tapes or adhesives should not be used on
enclosures (or directly on photos, by reference) because of the
tapes'  long term aging characteristics and other physical
characteristics, in addition to the fact that they may cause fading
or staining if they have failed the PAT.

These long term aging and physical characteristics that make
pressure sensitive tapes undesirable for use with photos (and most
valuable historic artifacts and documents) include the: 1)  tendency
to ooze with cold flow of the adhesive over time; 2) the tendency to
become difficult to remove during the middle stages of natural
aging; 3) the tendency of many to have oily components that migrate
out into the adjacent material causing transparency in those
materials during the middle stages of aging; and finally for 4) the
tendency to fail during the late stages of natural aging.  The PAT
does not test for these characteristics, only for interactions with
image materials and the gelatin emulsion (fading or staining).

For the above reasons, pressure sensitive tapes or adhesives, even
ones that pass the ANSI IT9.16 Photographic Activity Test, should
not be used on valuable historic photographs intended to be kept for
generations in a stable condition. For less valuable photographs not
of an historic nature, or those requiring only temporary use i.e.,
to be kept for a limited time period then discarded, then the use of
a tape that passes the PAT is preferable,  of course--at least
staining or fading would be minimized (if it occurs at all) during
the period that the photograph is kept compared to the use of a tape
which does not pass the PAT.

Use of the tape to seal paper or plastic enclosures should be
carefully evaluated the same way, and again a tape that passes the
PAT is desirable, as for the reasons stated above.  If tape must be
used to adhere together enclosures, it should not be used near edges
where adhesive cold flow could cause it to ooze onto the photograph
stored inside. Also, it would be safer to use on thick papers or
boards (or plastics instead of paper) where migration of oily
components would take a much longer time to reach the photograph,
hopefully longer than the enclosure would be needed for use before
replacement!

I can certainly think of a few circumstances where a conservators
might consider the use of a pressure sensitive tape, one that passes
the PAT, on or near a valuable photograph:  for example, sealing
cased objects to their cover glasses; using a double-sided tape to
adhere photo corners to an album page for housing of photos or paper
memorabilia, or for temporary display where traditional hinging is
undesirable (if done in a way to minimize the dangers from oozing
adhesive and oily components);  Less typical circumstances might
include: temporarily hinging RC prints for short durations of
display; where testing shows that the tape can be removed; and
replacement of failing (or disfiguring) tape incorporated into an
artwork intentionally.  There are perhaps some other cases that are
even more esoteric.  In any of these examples, there might also be
alternative options that would not require the use of a pressure
sensitive adhesive at all.

None of the above statements are meant in any way to endorse or
condemn any particular manufacturer's product, but to elucidate the
requirements of photographs and the complexity involved in the
evaluation of all adhesives and materials (not just pressure
sensitive ones) that one might use in conjunction with photos,
historically valuable or not.  The availability of adhesives
formulated to be the least harmful as possible in their class of
adhesives is always desired in the field, even if we may not use
them in all conservation applications (if only because we know
people will use them  and we will have to deal with any problems
that might arise as a result).

Sarah S. Wagner
Senior Photograph Conservator
Document Conservation Branch
Preservation Programs
National Archives and Records Administration
(also member of ANSI/PIMA Imaging Technology Stability Committees
responsible for the above cited standards)

                                  ***
                  Conservation DistList Instance 13:26
                Distributed: Wednesday, October 20, 1999
                       Message Id: cdl-13-26-001
                                  ***