Tissue and textiles

Rebecca Wehr <rrwehr [at] gmail__com> writes

>How many years is it safe leave textiles wrapped or rolled in
>acid-free unbuffered tissue paper before changing the tissue?

The issue of storage of textiles in tissue is a contentious one.  In
fact there is no single time or value possible..  If the textile
item is very old acidic and has acid dyes or inherent vice the
tissue will need regular changing as it absorbs the acidity and
ceases to be acid free.  Regular changing of tissue used with highly
acidic items is said to assist passively, in the removal of many
acids and aid conservation.  This can not be easily proven but is
surmised.  New items or synthetic ie: polyester items may not need
tissue changed often or if they have new synthetic paints, polymers,
glues or additions acidic/ offgassing may ensue and therefore the
tissue may need regular changing

The debate is further complicated with buffered paper: Does it
absorb more of the acidity?  Too much?  Too fast?  Will the
alkalinity do harm, causing fading, remove acid dye bonds?  Everyone
has an example which contradicts the expected.

Generally it is agreed buffered is not good for things which prefer
a little acidity ie: items with original gelatin sequins, sinew and
pH sensitive dyes for example.  Personally I believe if you feel
buffered is required interleave with acid free first so it is not in
direct contact with an item.  Then that acid free sheet yellowing
still can act as a bit of an indicator of what is going on and
reduce the risk of alkalinity causing damage.  Some items obviously
yellow tissue and need more regular changing.

Basically only by knowing exactly the chemical condition of the
textile can we really know.  Problem is we may never exactly know
the chemical condition of a textile.  In short if the tissue is
yellowing we generally agree it needs changing and has become
acidic.

Basically check your collection and make tissue replacement part of
your integrated pest checking and collection management.  Make a
note of when tissue is changed on the items catalogue file as this
helps monitor if items have been checked and how fast things are
changing. It may even point out clusters of items which are being
effected by an external element, such has poor ventilation or
unsealed off gassing cupboards.

Victoria Gill
Freelance Textile Conservator
Philippines


                                  ***
                  Conservation DistList Instance 24:46
                  Distributed: Tuesday, April 5, 2011
                       Message Id: cdl-24-46-009
                                  ***