American - English type. 1, Copper frame. 2. Glass plate (thick). 3. Copper passepartout. 4. Paper strips for sticking around.
5. Daguerreotype plate. 6. Velvet covered cardboard frame. 7. Case. |
This type is a case or box simi1ar to the Eastern-European one, the only
difference being that the hinge is on the longer side and its top is made of
ornate velvet. The picture part cannot be folded out of it but the bottom of the
box surrounds it as a fratne. It can be removed from this very easily. At the
very back, on the part taken out, the back plate of the sheet can be seen and
sometimes there is also another metal plate behind it. On its edges the edge of
the frame pressed of copper plate can be seen and this is folded on.
The plate
is followed by the copper mount with pressed decoration.
The opening is oval or
rectangular with sides of "}" form. The glass and the above embossed copper
frame can then be seen together with the adhesive tape underneath. This type of
frame is shown in the diagrams of every technical book on "How to treat
daguerreotypes". The disintegration of the adhesive tape used and the
decomposition of the glass are most common problems, as well as the loss of the
protective case.
Typically the shape of an oxidized frame appears on the surface
of the dag plate where the copper mount touches the plate. Further deterioration
can be prevented by lining the copper mount with paper.
Thus the side opposite
the plate is covered with paper. It is very important to remove the adhesive
tape stuck cound it. If there is enough room it is advisable to place an
additional glass plate behind the daguerreotype plate (for more isolation) or at
least a cardboard.
A thicker than usual (3-4.5 mm) front glass plate was used
since adhesive paper stuck round would show under the thin copper fcame; it is
therefore only present on the edge of glass.
The copper parts of the mount are
also subject to corrosion and their treatment is the task of the metal
conservator. There is also the question of what damage the remains of cleaning
agents might cause to the picture over a longer period since these might get
into the microclimate.
This type was probably dominanl throughout Europe in the first
half of the 1840s and remained in use in Germany, mostly in the east, longest of
all. Typically it had a board at the back, then the sheet which was frequently
suitable for the round Petzval Voigtländer camera, then the mount made of white
paper usually with an octagonal window. The frame was usually outlined for
decoration and the German versions were frequently more elaborate. The signature
of the photographer and the exposure time are often visible on the lower part of
two (askew) sides. The plate is held by the black cover and the mount is stuck
to it. Very often a separate raised edge was prepared for the internal fixture.
Then came the glass plate. The back cover and the sealing tape around it is made
of glazed black paper and in the case of Hungarian versions is finished with a
little cardboard strip stuck to the mount and the glass which improves the seal.
If it remains intact it provides good security. The weak points are tbe back
covering which is too thin, and tbe adhesives used on it which oxidise the
copper. Undamaged examples are rare and it is usually the glass ar the adhesive
tape which are damaged.