Paper Technology Journal 19 - Voith

66
19/05
Deep-frozen, dried – and saved
In the night of September 2nd, 2004, a major fire destroyed
large sections of the historic building housing the Duchess Anna
Amalia Library in the German town of Weimar. Local residents, library
employees and several hundred volunteers formed a human chain and
rescued more than half of the irreplaceable original manuscripts and
incunabula from the burning building, which is on the UNESCO World
Cultural Heritage list. Some 30,000 of the library’s volumes were
passed from hand to hand in this way, and a further 30,000 also
escaped the flames, though damaged to a greater or lesser degree.
Most of the books that were rescued,
were already singed or soaked in water
as a result of the fire-fighting operations.
They were taken temporarily to the Book
Preservation Center (ZFB) in Leipzig, an
institute possessing expertise unparalleled
anywhere in the world in the saving
of old books, periodicals and musical
scores for posterity, and the restoration
of old maps and plans, certificates and
official records.
Months after the catastrophe in Weimar,
visitors to the ZFB can still detect a slight
smell of smoke and burning in the air. It
emanates from the ‘patients’ brought
there from the Anna Amalia Library.
These are stacked everywhere in the
workrooms and corridors. Some have already
been given initial treatment, which
involves sorting and classifying them into
groups according to the degree of damage
they have suffered. Group One consists
of largely undamaged items, whereas
Group Six contains those that have
been almost completely destroyed.
The first treatment stage for the books is
to be stored temporarily in large cold
storage chambers at 20 degrees Celsius
below freezing point. Wrapped individually
in muslin or fleece, each soaking wet
book is transformed within a very short
time into a frozen-through block of ice.
This technique avoids further loss of
shape or disintegration, but more importantly
prevents the spread of mold spores
and is a means of gaining valuable time.
Although the Institute is working round
the clock in three shifts, its skilled methods
of limiting damage are unavoidably
time-consuming. Nobody expected to be
confronted with tens of thousands of
books, all needing urgent attention to
protect them against irrevocable damage.
The second stage in the treatment
process is freeze drying – using a method
that the ZFB itself developed to extract
moisture from the books. If they were to
be allowed to dry in a normal atmosphere,
the inks, color pigments and glues
would run, the pages would tend to stick
together and the paper would become
wavy and brittle. In other words, even
worse damage would be caused. Freeze
drying, on the other hand, prevents the
moisture in the book, once it has been
turned into ice, from thawing again in the
conventional sense of the term. It trans-