Putting on an exhibition is a huge undertaking and involves
staff from across the Museum. Much of the hard work happens in the
Museum’s science and conservation laboratories where objects are
studied and prepared for display.
Among the millions of objects in the Museum’s collection
is an extraordinary group of watercolours produced by
Englishman John White during voyages to 'Virginia' (now North
Carolina in the United States of America) in the 1580s. White’s
images are the earliest surviving visual record by an Englishman of
the animals, plants and people of America. They offer a
fascinating glimpse of the strange new world encountered by the
Europeans of the late sixteenth century. A
recent exhibition of these unique
drawings gave Museum scientists and conservators a
fascinating opportunity to study and treat them.
The watercolours were originally bound into an album. In
1865, before it was acquired by the Museum, the album was damaged
when a warehouse in which it was stored caught fire. Some of
the pages were scorched and when the fire was put out, the album
was soaked with water and remained wet for a number of days. This
caused pigments from the original drawings to be offset onto
interleaving pages. After this incident the drawings were placed in
a new album and, at various times during the last century, have
been individually mounted.
In preparation for the exhibition, the Museum’s team of paper
conservators studied the drawings carefully to assess their current
condition, examining the damaged paint surface under high
magnification to ensure it was stable. Scientists analysed the
pigments on some of the drawings. But because both the paper and
the layers of paint were very fragile, it was not possible to take
microscopic samples or analyse the pigments using techniques which
might involve contact with the surface. Instead they used a number
of non-invasive techniques: optical microscopy, Raman spectroscopy
and X-ray fluorescence analysis.
Optical microscopy enlarges the image of the object and paint
layers to allow materials and surface treatments to be identified
based on their appearance. X-ray fluorescence works by directing an
X-ray beam at the object and Raman spectroscopy by shining a laser
beam onto the surface and both of these methods allow scientists to
identify and characterise materials such as pigments from the
spectra produced.
The analysis enabled the scientists to identify the wide range
of pigments White had used to create the vivid colours of his
subjects. Their results showed, for example, that he had used three
different blue pigments – smalt, azurite and indigo – to capture
the colours of the feathers of the European Roller. The results
also demonstrated that some of the pigments have changed colour
over time, and with digital reconstructions it has been possible to
get some idea of how the drawings may have looked originally.
Conservation methods and principles have changed a great deal
over time. In the eighteenth and nineteenth centuries, the aim was
to restore damaged objects in an attempt to reproduce the original
appearance. Today the main aim of conservators is to stabilise and
preserve objects and, wherever possible, to use treatments which
can be reversed.
In the case of the John White drawings, the staining and changes
to the pigments are now accepted as part of their history and were
not treated. However, undulations in the paper required flattening
and the fragile edges, which were at risk of further damage, needed
to be repaired. Traces of old adhesive and paper debris on the back
(verso) of the drawings were carefully removed.
The damaged edges were then supported, using carefully matched
Western papers and layers of Japanese tissue adhered with a pure
wheat-starch paste. Undulations were removed by humidifying the
drawings and then pressing them between blotting paper and boards.
Conservation treatments and remounting have not only improved the
overall appearance of the drawings but also provided greater
protection for the future.