Daguerreotype

As a daguerreotype photographic processes of the 19th century is called (short Dago mentioned in the collector's jargon ). It is named after the French painter Louis Jacques Mandé Daguerre, who developed it 1835-1839. The daguerreotype was a ready -trained, fully practicable system already in its publication.

The rights to the procedure were acquired at the initiative of the physicist François Arago of the French government. She paid for a lifetime pension to Daguerre and Isidore Niepce to the son of his former partner Nicephore Niepce. Arago presented method on 19 August 1839 in a joint meeting of the Paris Academies of Sciences and the beautiful public arts. Then it stood as the first practicable photographic process, everyone for free and free usage available. Excluded, however, England was due to the previous granting of a patent to a licensee Daguerre.

Characteristics

The daguerreotype is a photograph on a mirror -polished metal surface. For this purpose, silver-plated copper plates were used by mostly 0.65 to 0.75 mm thickness in the rule that was sold under the name silver plaque by the manufacturers silberplakierter goods. The pure silver plates initially used by Daguerre proved to be too expensive, cost-reducing variants with unversilbertem copper or silver thin film had disadvantages.

The daguerreotype delivered well from the start nuanced and finely textured images to be viewed with a magnifying glass still show the smallest of details. It justified this, already at the beginning of the history of photography to a high standard, against which all subsequent proceedings had to be measured. The image tone, originally a light gray to blue gray, could also be yellow gold and thus achieve a more natural effect after insertion of the presented by Hippolyte Fizeau on March 23, 1840 gold toning. Weaknesses of the method are a high health risk for the photographer (handling toxic fumes ) and a laterally inverted image of the recorded subjects. A deficiency was in the early days beyond the fairly low light sensitivity. In addition, each daguerreotype is unique, that can not be duplicated easily, but what were their appreciation rather increased. A special and very characteristic limitation is looking at the pictures: The shadows of the images are represented by bare silver. Depending on whether it reflects light or dark, you can see a daguerreotype negative or positive ( it is, however, the positive process attributed ). This inconvenience was a main reason for the rapid success of subsequent procedures.

Cultural-historical importance

After they were mainly used in the early years in the 1840s due to the long exposure time for architectural photography, daguerreotypes soon gained particular as small-format portraits popularity. They were cheaper than the usual up to this time painted miniatures, but this unsurpassed, then surprising fidelity. They are therefore presented in elegant boxes or similar representative picture frame. The lack of color in the pictures was mostly fond accepted. However, also the coloring already developed to a high bloom, especially at the nudes mostly produced as a stereo recording in Paris. In addition, almost every other application of photography have been justified by Daguerreotypes. In addition, for example, still lifes, reproductions of paintings or graphics, science and travel photography has also contemporary events held. The photographs of the ruins of the fire disaster in 1842 in Hamburg by Hermann Biow are considered the beginnings of photojournalism in Germany.

Popularity

Through the publication of the daguerreotype in 1839, photography was able to spread early in their history within a few months all over the world. The Daguerreotype enjoyed until the late 1850s great popularity. In the clarity and detail she was also the first negative-positive process of talbotype (also known as " calotype " ) by William Henry Fox Talbot clearly superior, that was mainly in use at the same time in the UK. She was, however, because of the annoying mirroring - unlike the Calotype - for large image sizes or as a wall decoration hardly suitable. The daguerreotype process was in Europe until the mid- 1850s, predominantly (in the U.S. for a certain time longer), was from then on one hand, but by the collodion negative process, and albumin prints (especially the cheap business cards - portraits), on the other hand, displaced by the based on this new technology, positive process of ambrotypes. These were also unique, therefore, served as a replacement for the daguerreotypes and were framed similarly precious. However, daguerreotypes are coveted collector's items since about 1970. In addition, since artistically ambitious photographers have taken over the world, the process as a separate stylistic device again.

Method

Daguerre had worked with Nicéphore Nièpce, the inventor of heliography in partnership since 1829. His method, however, developed independently, based on completely different principles than the heliography.

The daguerreotype is based on the light sensitivity of silver halides. The silver-coated copper plates were first carefully polished and then made ​​light- sensitive by exposure to iodine vapor. Later, the plates were exposed to additionally also bromine and chlorine vapors, which considerably increased the light sensitivity of the plate. By vapor deposition formed on the surface of the silver layer of silver iodide or silver bromide. The plate had to be subsequently stored in the dark and used as soon as possible, because it was only for a short shelf life. During exposure ( " exposing " ) sat they on the back of a camera the incident through the lens of the camera light. On its surface, a head protruding and ( in plan view ) was also projected reversed image. Because of the low sensitivity of silver iodide took an exposure to the sun first ten to fifteen minutes later, however, by improvements in the process and the lenses less than half a minute, so portraits were possible. In the exposed areas of the recording, the silver halide is reduced to metallic silver. It was then developed with the help of mercury vapors. On the base plate thereby superimposed on the previously taken by the light parts of the image very faint silver mercury droplets. After fixation, initially in a sea salt, and later a " hyposulfite " ( thiosulfate ) or potassium cyanide solution, with dissolved the remaining light-sensitive silver salts, was an extremely light-stable, light gray image. However, the mercury precipitate was extremely sensitive to touch. The support plate is therefore mounted with a mat behind a pane of glass and air-tightly bonded thereto to protect against oxidation, before being put to their final enclosure ( box or frame).

Cameras

Special cameras for the daguerreotype process were initially offered by the firm Susse Frères and a few days later with Daguerre's personal license ( indicated by its signature on a plaque screwed ) by its brother Alphonse Giroux in September 1839. It was in the evolved from the camera obscura apparatus so-called sliding box cameras. Their enclosures consisted of two nested parts, with which one could make the distance setting. As a closure, a simple cover was on the lens which has been removed during the exposure by hand and put on again.

From the Daguerreotype sliding box camera manufacturer Susse Frères of Paris is only one copy known. It was auctioned in May 2007 for € 576,600 in Vienna.

From the little younger Daguerreotype camera from the manufacturer Giroux, there are about ten pieces in museums worldwide. Another camera of this type was until 2010 in Northern Germany are privately owned. The apparatus was auctioned along with its German original instructions by a Viennese auction house on May 29, 2010, net 610,000 euros or 732,000 Euros including buyer's premium and was then one year the most expensive camera in the world. However, an even higher price was achieved for a Leica On May 28, 2011. The Giroux Daguerreotype camera - already had a magazine that had received the support plate and was pushed into the apparatus before the exposure instead of the ground glass required for the settings.

The exposure time was able to be reduced significantly in 1840 with the first scientifically calculated portrait lens of the Viennese professor Josef Petzval ( see Article Petzvalobjektiv ). The optician Friedrich von Voigtländer built it in order Petzval first. It had 16 times the aperture of the lens used in the Giroux cameras.

Simultaneously with the lens - and of course equipped with this - developed Voigtländer also a stand-alone camera system for daguerreotypes. His machine was first made ​​entirely of metal and had the shape of a cone. A second cone bore the focusing screen and a viewing loupe. It has been screwed onto the former, to prepare for recording, so that the camera then had the shape of a double cone. As an accessory there was a table-top tripod with two forks, in which one the apparatus loosely put there to align and focus the image. Before exposing the daguerreotypist wore the whole camera into the darkroom, unscrewed there instead of viewing module to a magazine that contained the circular in this concept support plate, and put the camera then back to the provided table tripod. Also for the final processing of the whole apparatus was worn into the dark again. The system was robust and reliable, but set to a particular disk size and an unusual form of images.

Plates

The plates were factory-made, from all over the plate, cut by photographer on each size needed. These may differ in individual cases differ from those given in the following table easily. The price of a dozen silver-plated copper plates of standard size 216 × 162 mm was in Germany initially at just over 42 Courant marrow,. A finished recording in almost 17 Courant Mark