PRESERVATION OF WALLPAPERS AS PARTS OF INTERIORS

Preservation of wallpaper as a part of interiors
binding medium. Secondly, the type of wallpaper and methods
of manufacture should be determined. These two stages can be
carried out by a conservator.
The following stages should be carried out by an art historian
or in co-operation with one. They include identifying pattern
styles, evaluating the context of the physical evidence and searching
for additional information in archives and museums. 319
Since historic interiors form a complex unity of various
decorative methods and means, it is highly recommended that
experts from various disciplines be involved: conservators of
other materials, art historians, architects, chemists etc.
4.2.5. Testing paint and paper
Although several types of damage, such as tears, holes, flaky
pigments, brittle paper, darkened residues of adhesive, growth
of mould, and tide-lines, can be revealed through observation,
a number of additional tests should be carried out on paint and
paper. Materials and methods should be chosen according to the
results of tests. Several methods have been applied to quantitatively
describe the effects of ageing on a paper support. 320
The basic tests to be conducted involve the solvent resistance
of printing paints, presence of mould spores, pH of paper
and, less often, pigments and fibres. Of the latter, the most frequent
aim is to determine the level of lignine in paper, since it
may turn dark when washed.
The acidity of paper depends on the raw material used, the
methods of manufacturing and the subsequent preservation
conditions, and has a significant impact on the durability of the
material. Historic rag papers tend to have a neutral pH (in the
range of 6.0–7.0) and a long life expectancy. Wallpapers produced
after the mid-19th century are often made of wood-pulp
fibre and have inherent instability problems from the lignin and
319
Frank S. Welsh, “Investigation, Analysis, and Authentication of Historic Wallpaper
Fragments” in JAIC Online, Volume 43, Number 1, Article 7, accessed June 5, 2013,
http://cool.conservation-us.org/jaic/articles/jaic43-01-007.html.
320
Joel et al., “The Measurement and Significance of pH in Paper Conservation” in Bulletin
of the American Group – IIC 12, No. 2, April 1972 (1972), accessed December 7, 2012,
http://www.jstor.org/discover/10.2307/3179136?uid=3737920&uid=2129&uid=2&uid=
70&uid=4&sid=21101350589173.
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