Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Doug I.
<puzzolente@s...> wrote:
> I've noticed the hinge outline popping up too lately with the
Lineco 
> gummed archival hinging tape. I don't think it has so much to do
with 
> the hinging method used (well...unless you were using a really thin 
> tissue), but more to do with the really powerful spring clips that
come 
> with the Nielsen frames I buy. They put a lot of pressure on the 
> mat/photo/glass sandwich.

I doubt that that this can explain the "outline" problem--which I
haven't (yet) encountered with my Lineco hinging tape. The Nielsen
springs do exert a lot of pressure, but it's concentrated at the
extreme edge of the sandwich. With the usual cardboard backing, this
pressure will likely be very much diminished within the window area of
the mat (unless your mats have _very_ narrow borders). However I
wonder if the outline problem might be due to your method of hinging:
do you use a "T-hinge" or a "V-hinge" method?  With the "T" method the
hinge is taped to the backing board well _above_ the print (under the
mat border) so that only a relatively short, single layer of tape is
under the print. But in the "V" method, the hinge is _folded_ and so
several layers of tape lie beneath the print, and this could increase
the possibility of a visible outline.

Another possible explanation for development of a tape outline could
be if there's any differential swelling/shrinking between the print
and tape. For example the print paper might undergo a slight overall
expansion due to humidity changes, but this change might be prevented
within
the small area(s) that are tightly glued to the hinge tape. This then
might
produce an outline of the hinge--especially if the glue (gum) dries
down to a rigid, glassy substance (gelatin glues do this). Of course
the liklihood of humidity-induced dimension change depends very much
on the paper type.

Phil