Daguerreotypes were first made in 1839 (1840 in Hungary). But the
main type of deterioration (and the way of prevention) was well
known a long time before the invention of this process, because it
is the same in the case of any silver thing. It is the dark bluish
purple iridescent layer created on the surface by gases (primary
sulfuric) in the air. It appears first on the edges of the plate,
although there are exceptions, and from there it spreads to the
middle and makes the images invisible. Subsequent deterioration is
also related to this problem. The causes lie partly in the
application of incorrect conservation methods and partly in the
deficiences of the protective packaging. Other damages caused i.e.
when the picture was created or inner oxidation occur more rarely.
This suggests immediately that the primary task of the conservator
should be the elimination of deficiencies of the protective
packaging and its due maintenance.
Though essential elements of the packaging (amongst which I include
case, decoration or mount and I will use instead of these in this
text a collective name "installation") have been known from 1839
(and can be seen on early pictures made and dedicated by Daguerre in
exhibitions, collections at Budapest, Prague and Munich) and thanks
to Jakab Zimmerman an Hungarian translation of the original
description appeared as long as 167 years ago, but when I had been
working with daguerreotypes of collections I couldn't see it too
often. Although it is not very difficult to put the daguerreotype
between the glass plate and the backing board and to seal it
hermetically with a strip of paper the only - made in Hungary -
picture of Kossuth (an outstanding Hungarian politician) and the
only surviving landscape were both ruined due, in part, to the lack
of such protection. The only existing photograph of Petofi (a great
Hungarian poet and freedom fighter) fell victim to the combined
process at first the broke glass made by oxidation and then the
potassium cyanide used for "cleaning". The case of the Kossuth
portrait is very instructive. When it was returned to Hungary in
1930 a huge ornate box covered with red velvet was made for both it
and the accompanying copy in a fervour of patriotism. But no-one
thought to replace the missing glass (until 1989). The result is
visible: the picture has entirely disappeared. None of the
daguerreotypes I have examined were free from the effects of
oxidation and the purpose of this lecture is to ensure that, in the
future, there will be fewer unfortunate tales and more surviving
First some general observations.
It is important that as much of the installation is kept as possible
since it is both an integral part of the whole as well as the bearer
of certain information. It means that we must not discard
heartlessly, or rigidly, that which might be judged to be Utopian or
out of accord with the general principles of conservation. In most
cases it will be sufficient to dismantle the packaging in such a way
that it is possible to put each part back in its original place. To
this end it can be useful to know about different types of
structure, especially when it is necessary to construct missing
parts in a professional and sympathetic way.
Every medicine can have side effects that is also true for
protective enclosures. Unsuitable materials or methods of
construction can damage the photographic plate. Problems are both
specific and general, for example if the sheet with the image is in
contact with glass, paper, adhesive or metal which cause oxidization
- especially if the decomposition of glass has already started. If
it is not caught in time it will spread and increasingly eat through
the silver layer. Damage is also caused by the harmful evaporation
of substances in the air-space surrounding the sheet.
If the decomposition of glass has already
started. If it is not caught in time it will spread and
increasingly eat through the silver layer.
The function of the daguerreotype installation can be divided into
two groups. The sealed part ensures the stability of the
micro-climate round the sheet and the ornamental part covers the
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.
Early (German) type. 1. Gold coloured
decoration strips (optional). 2. Paper strips for sticking
around. 3. Glass plate.
4. Passepartout. 5. Daguerrotype plate. 1. Back cardboard.
7. Back covering paper.
2. The (Central-) Eastern European type
The left picture is the
property of the Hungarian
Museum of Photography.
The right picture is a reproduction, Lajos
(1807-1849 prime minister of the 1848-49 Hungarian
freedom fighting, killed by the Austrian occupators), from the
(1810-1898) lithography (owned by the Hungarian National Museum).
The (Central) Eastern European type. 1.
Velvet cover for passepartout. 2. Cardboard holder for
passepartout. 3. Cardboard strips for holding the glass
plate. 4. Glass plate. 5. Daguerrotype plate. 6.
Silk hanger. 7. Combined back covering paper and
cardboard for propping the picture up. 8. Case.
This is the most complicated type. The majority of Hungarian
daguerreotypes and those found in Hungarian collections which were
made in the second part of the 1840s are in this type of
installation. The part containing the plate is in a case made of
wood, some times embossed and covered with dark brown, rough paper
which simulates leather. The upper part of the interior is mostly
lined with a white silk pad. The opening is restricted to aboat 100
degrees by a smalt silk tab sticking out at the top and can be held
in place by a cardboard support on the back at an angle of about 45
degrees. The lower part of the cardboards and the boz are, in rnost
cases, covered with the same glazed or embossed paper (which is
susceptible to water damage). The paper sheet used as backing for
the part containing the plate is usually the same as the material of
the decorative cover ie.not cardboard. This
is followed eitber by some more cardboard stuck to the back of
the plate (ocassionnlly of different thicknesses) or just the plate.
The cardboard frame round it äzes the plate and the glass in front
of it. Right at the froat there in a mount of velvet stretched
over the cardboard, except for an octagonal window. On
the outside the (wine) red, blue or green velvet entirely covers the
sides of the casiag and stretches over the back to a depth
of approximately 1 cm. The ornate back paper was stuck to
this. The velvet is usually decorated with pressed patterns and/or
a gold coloured embossed cardboard strip. The
repeated pattern is mainly of circles, lines or flowers.
Gilding is normally glossy. A typical defect of this
protective case is that air and dirt always
penetrate under the glass. Frequently there is nothing
tween the glass plate and the daguerreotype to prevent them touching
each other. In practice near all the pieces need repair. The plate
should be stuck, if possible, in between two pieces of glass so that
there is a small piece of paper between the first glass and the
plate to prevent contact. Then a thin paper should be stuck on to
both side, the back glass plate to prevent breakage. If the
thickness of the glasses is too great and there is
insufficient room in the mount then cardboard should be used.
Sealing with paper tape will make airtight. This tape can be
double-sided and it is recommended to separate pieces should be
stuck on to the cornecs. If the original glass is too small, or
deteriorating (obvious from the small drop-like spots on its surface
or fine crazing should be changed. There are further reasons
why a thorough examination of the installation is important. It can
happen that the photographers card or that of an unknown
photographer is hidden beneath the cover of the case; it can also be
that the earlier restorer has completely changed the nature of the
original. The latter is more properly subject of another lecture.
West European type. 1. Paper for sticking
around. 2. Glass plate with painted "passepartout". 3. 4.
5. Passepartouts gold, silver
and black coloured from cardboard (silver and black are
optional). 6. Daguerreotype Plate. 7. Back cardboard with
"door". 8. Hanger (usually metal). 9. Back covering paper.
Elements of the West European type (a
simpler version, with less decoration parts).
Daguerreotype plate, back
cardboard with "door", passepartout (mat) gold
cardboard, back side of the glass
plate with painted "passepartout"
This method was mostly used in France, in the western part
of Germany and in Switzerland. (It was also used occasionoally in
Hungary as in the case of the picture of Lajos Kawalky). It has
cardboard under the black plate, covered with brown paper. (In
earlyer e~camples glue was used as an adhesive but here it is likely
that starch, which is not easy to dissolve will
have been used.) In the middle of the cardboard there is a
small flap the same size as the plate; the latter was inserted
through this before being fixed in place by gummed paper
usually blue. The flap was then closed and stuck down
with the back cover paper. This is also the best way to
dismantle the case, the parts being found in reverse
order. First the cardboard with the flap, then the plate stuck on
thin paper, and finally the cardboard parts of the mount
in several layers. The shape of the window is
rectangular with round corners or, more rarely, oval. First there is
the black plate with the smallest opening followed by a white or
silver one, followed by a thick, gold coloured plate with a bigger
opening and edges cut in an angle and finally a further silver one.
The glass plate follows, The major part of the mount is painted on
the inner side of it. Most frequently there is a decorative stripe
of gold-coloured metal foil on a black or brown base which follows
the main shape of the window painted on the glass and is often in
tbe form of a "}" or sometimes only the ornate strip is of this
design. Other ornaments also appear. If the whole is intact it
provides good protection for the picture but the glass plate is
frequently broken since it usually lays on an uneven surface. In
this case another has to be painted or the original has to be mended
with Canada balsam. An alternative which is quite acceptable is to
place another glass plate underneath it. The adhesive tape round the
edge is almost always damaged. The original paper, which has a
characteristic colour is always one piece, smoothed over the corners
with careful folds. This is characteristic of this type of
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.
The shape of an oxidized frame appears on
the surface of the dag plate where the copper mount touches the
plate. (Usually a complicated form of the copper mat
window and the more decoration meaning a later product.)
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.
A comment for 1.-4.: The type of
installation doesn't determine the place of origin ofthe daguerreotypes since they are
not neccessarily found where they were made nor isthere always any definitive evidence.
5. Atypical occurrences
Rules are usually strengthened by exceptions and there are plenty of
exceptions in this subject. Naturally, in addition to the types
mentioned above, a wide variety of frames were made. Most are
deviations from or varieties of those noted but there are some which
are quite different.
The mounts made for stereo-daguerreotypes usually differ from the
normal types made at the same time (and in the same place). The
difference lies not only in the fact that there are two pictures and
often a stereo-sighting slot as well. The structure and appearance
are also different, but I have not had sufficient experience to be
able to present them here. The mount made on the French material is
similar to other, Western European, normal types but the structure
is much simpler. Those made in this Hungarian region show great
variety. Most of them, however are similar to the types
already mentioned, regarding one or two characteristics.
Those frames into which daguerreotypes were fitted after
they were made should not be forgotten. Most of such frames were
made not for daguerreotypes but mainly for normal paper prints and
at the time at which they were re-used the special requirements for
daguerreotypes had been forgotten. It is best if the plate is put in
place with part of the old mount but it is rare and usually the
unsuitable mount causes serious damage. Frequently there is a copper
inlay in the mount window with small plates sticking out from back
and folded onto the back of the plate pressed on to the front glass.
This method lets in air and the glass and the daguerreotype can
cause each other damage. In some cases glass is not used at all in
which case it is important to try to create a micro-climate and
place it in the original installation..
8. Plate only
Unfortunately it is very often only the plate which survives. If,
from remaining traces (some evidence of the mount, shreds of paper
etc.), the existing data or older reproductions, it is clear what
type of mount it might have had a similar one can be made. If it is
unclear or impossible to create a simple, undecorated protective
packing will also do. (The plate should be between two sheets of
glass, behind the mount with small pieces of cardboard to make
distance between them, an adhesive tape around and be covered with a
The storage, cilmatical conditions, or light effect results.
Information is lacking about the effects of environmental conditions
and light on daguerreotypes either in storage or on exhibition. (It
must be remembered that the white parts of the picture are made from
a mercury-silver amalgam and that when heated the mercury
evaporates. Care must be taken about warm as a result.) Indirect
effects are known. Unfavourable conditions cause damage to the
protective packaging, for example the result of frequent and
substantial changes in temperature is the disintegration of the
installation due to differing rates of thermal expansion; a poor
climate can damage the paper and textile parts of the casing and
cause the corrosion of the copper parts.
For permanent exhibition, or if the appropriate conditions cannot be
ensured it is advisable to use good quality facsimiles as in other
photographic media. In this way reconstruction facsimiles can
also be made of pictures such as those now invisible as a result of
oxidation and can be presented near as they were originally. By
facsimile the same picture can be displayed at several exhibitions.
If there are those who really must see the original it is possible
to announce that it will be exhibited for a few days only which will
greatly reduce the risk. It must be remembered that the opportunity
to see even a mediocre popstar in the original is infrequent as
( Text based on the translation of Magda Milkovics and Helen Forde,
for the postprint of the Conference on the Book and Paper
Conservation Budapest 1990 - with continous modification by me...)