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Conservation and restoration
We decided early on that measures of restoration, applied
to individual photographic originals, could only be adopted
in specific cases of evident urgency. Our reasons were partly
financial - restorative action, properly carried out, is very
expensive. But we also considered that there are other, fundamental
reasons for not attempting positive steps of restoration for
the bulk of the photographs in our collection. As we see it,
every photographic print or negative is subjected to the law
of entropy, and is undergoing chemical changes which affect
its quality at an unknown rate, depending on factors which
are not always apparent and are understood only in the most
general terms. This makes the methodology of attempts to reverse
the process of decay extremely difficult to define in individual
cases.
One might, of course, come to a rather different philosophy
of conservation and restoration in a collection which consists
of a relatively small number of individually outstanding photographic
images ("works of art") which are regarded as a capital investment.
In such a context, an active policy of restorative intervention
may be appropriate and financeable. However, the pictorial
collection in the Basel Mission archive consists of a relatively
large number of images primarily of documentary value. This
value is strongly enhanced by the density of the photographic
record - i.e. the frequency with which the same people, objects,
and events are photographed in the same place or district,
at the same or different times. Some photographs in this collection
may be, as individual images, of only modest value, aesthetically
and even historically speaking. But every individual photograph
can be a node in the kind of large network of sources one
can put together in this archive to support specific historical
investigations. This means that the very size of the collection
is one of its strengths, and restoration interventions with
individual images must be subordinated to stabilising, by
conservation measures, the collection as a whole.
In the face of this situation our conservation philosophy
has been simple. Besides rephotographing originals using film
designed for long-term stability and thus documenting for
several generations of scholars their state at the beginning
of the 1990s, we aim to store them under stable conditions
and to subject them to as little handling as possible, relying
on this to delay processes of decay in the originals as long
as possible. After the completion of cataloguing an individual
photograph will now only be taken out of the strong-room in
extraordinary situations - e.g. if it is to be published as
a high-quality print and we need to make a modern reproduction
for this purpose, or if it is to be exhibited, under appropriate
safeguards, as a vintage print.
In the mid-1980s Canton Basel-Stadt and the Swiss Confederation
subsidised the building of a Kulturgüterschutzraum
(a protected magazine for cultural objects of international
importance) for the Basel Mission archive. This is a fire-
and flood-proof storeroom with controlled atmospheric conditions.
The pictorial collection is stored in this facility. A stable
environment is thus assured. However, we do have the problem
that at the time this store-room was planned it was not realised
that separate accommodation for photographs and manuscripts
is advisable. Since the storeroom also contains the the manuscripts
of the Basel Mission archive, a compromise must be found in
setting the air-conditioning between the needs of photographic
materials and manuscripts. Although the ambient temperature
is satisfactory for most kinds of non-colour photographs (18-20°C)
the relative humidity is rather high, at 45-50%. We are advised
that optimum humidity for photographs would be 35% (+/- 5%)
and for other archival materials 50-55%.
Within the Kulturgüterschutzraum the positives
and negatives are stored in boxes constructed of "MicroChamber"
cardboard which has been designed specifically for the storage
of photographic images. Its interior surface is chemically
inert, and the cardboard structure contains an active carbon
filter. The large-sized albums are stored in boxes made from
acid-free unbuffered cardboard. Within the boxes the individual
images are separated from one another by paper produced by
Munktell and specifically designed for storing photographs
- it is porous and, again, unbuffered. With the glass plate
negatives this takes the form of 4-flap envelopes. We use
this somewhat porous material for images which have neither
been restored nor completely cleaned, since we consider that
this provides better conditions if slow chemical reactions
are taking place than do airtight materials like Mylar
film. For very delicate objects like daguerreotypes we use
silver-safe papers, which are more airtight but also have
a much finer surface structure. The paper inlays for albums
are individually cut sheets of a soft tissue which is normally
used as underlay material for restoring papers or photographs
("fleece", producer: Barcham Green & Co.).
The positives on paper and carton are, on the whole,
not seriously dirty, and we did not attempt to clean them.
The backs of the glass plate negatives and both sides of the
glass lantern slides were cleaned with pure alcohol.
Although conservation has been our primary aim, we
have had a small budget for restoration. Our original plan
was to use it to stabilise the situation of our daguerreotypes,
which were deframed in the 1960s. In recent months, however,
in consultation with C. Brandt (Neuchatel), who also made
an important survey of the physical condition of the collection
in 1990, we have decided that since the question of the restoration
of daguerreotypes is the subject of keen debate among experts
at the moment, we would postpone work on this part of the
collection. Instead we are having restoration and curative
work carried out with our ambrotypes - equally a pioneer photographic
technique which needs careful handling. We hope to raise further
funds to cary through proper restoration work on our albums.
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