PRESERVATION OF WALLPAPERS AS PARTS OF INTERIORS

Preservation of wallpaper as a part of interiors
hemicellulose left in semi-processed papers. 321 Their pH is 6.0
and lower. Acidic paper ages more quickly; it is mechanically
less resistant and sensitive to changes in the environment. 322
pH-meters with special flat electrodes or pH indicators, such
as pH pens, are used to measure the acidity of wallpaper, since
they are the least destructive.
To examine the solvent resistance of printing paints, the
solvents that might be used during the course of the conservation
process are tested: saliva, distilled water, ethanol (40% and
100%), acetone, ammoniac, hydrogen peroxide and adhesives
with surface-active substances, such as methyl cellulose. Tests
are carried out with cotton swabs wetted in a solvent, which is
gently rolled or pressed onto the printed surface and kept in place
for about five seconds. A runny or sensitive paint will leave a
mark on the swab. Besides indicating easily dissoluble printing
inks, the test shows whether the printed layer is sensitive to the
pressure to be applied if the layer of lining is removed.
Testing a wide range of properties, such as tearing, tensile
strength, fold strength, reflectance and elongation related to the
ageing of paper, can be carried out as well. However, they are
not very common in everyday conservation projects. After the
fold endurance test lost its importance as a means of evaluating
paper strength, an indicator which determines the length of
cellulose polymer chains, called the degree of polymerization
(D.P.), 323 has been used by conservation specialists.
4.2.6. Dismounting and packaging
Current preservation theory strongly favours preserving a room
of original or early wallpapers rather than removing and reproducing
them, 324 since wallpaper is considered to be an immovable
321
Basic Conservation of Archival Materials, Chapter 6 – Collections, Revised Edition,
Canadian Council of Archives, 2003, accessed December 7, 2012,
http://www.cdncouncilarchives.ca/RBch6_en.pdf.
322
Raamatukahjustuste atlas , Paberi pH määramine, accessed December 7, 2012,
http://paber.ut.ee/ET/kategooriad/sisuplokk/paberi_ph_maaramine.
323
Leslie M. Kruth, “Paper Conservation Update: Bleaching and Fumigation” in Abbey
Newsletter, Volume 13, Number 5, September 1989, accessed December 7, 2012,
http://cool.conservation-us.org/byorg/abbey/an/an13/an13-5/an13-516.html.
324
Nylander, Wallpapers for Historic Buildings, 16.
176