By Tania Passafiume and Jennifer Roger

The Daguerreotype, a one-of-a-kind photograph, was largely produced between 1839 and 1864. It was the first publicly-available photographic process and was renowned for its image detail and clarity.

The photographs are highly susceptible to image loss, corrosion build-up and other forms of deterioration caused by poor handling and environmental exposure.

To protect the image, the photographic plate was delicately placed under glass, from which it was separated by a protective mat.  This assembly was then hermetically sealed using paper tape and covered with a brass foil called a “preserver”. The entire package was housed in a small, often decorative, case made of leather, wood, papier mâché or moulded plastic, with an interior lining of silk or velvet.

Daguerreotype hallmarks or plate marks

Makers’ marks, known as hallmarks or plate marks are stamped markings found on many, but not all, daguerreotypes. When they are present, they are often found on the edge of the plate and are, thus, invisible when the daguerreotype is sealed. Marks typically consist of initials, symbols and numbers. The number most commonly found is “40”, which refers to the physical makeup of the plate, 1 part silver to 39 parts copper. Plate marks can offer clues about where the copper plate was manufactured and where the photographer sourced materials. They can sometimes also help to date an image.

When daguerreotypes were being prepared for the exhibition at the National Gallery of Canada, several of them were found to contain plate marks.A hand-tinted daguerreotype of three young women. The woman in the middle is standing between two women, who are seated.

One particularly interesting example was found on the daguerreotype known as The Three Ladies of Saint-Ours, which was produced between 1850 and 1860. The portrait features three sisters from the Saint-Ours family, one of Quebec’s foremost seigneurial families: Caroline-Virginie (1835–1894), Josephte-Hermine (1834–1900) and Henriette-Amélie (1837–1916).

The Three Ladies of Saint-Ours (Caroline-Virginie, Josephte-Hermine and Henriette-Amélie) 1850–1860 or thereabouts (MIKAN 3207932)

An upside down, partial plate mark was found on the left-hand side of the bottom edge of the plate. This is an unusual location, as most plate marks are at the top or bottom corners of daguerreotypes. The mark includes the inscription “C,C”, a symbol of a scale and the name “CHRISTOFLE”. The name is also written under the image.

The Three Ladies of Saint-Ours (Caroline-Virginie, Josephte-Hermine and Henriette-Amélie) 1850–1860 or thereabouts, plate mark detail.

The marks confirm that the plate was made by Charles Christofle et Cie, a company from Paris, France, that sold plates for daguerreotypes during the nineteenth century. These plates were primarily used between 1845 and 1862, which corresponds to the estimated date of the portrait entitled The Three Ladies of Saint-Ours. The inscription “C, C”, which forms part of the mark, stands for Christofle et Compagnie, while the scale has been used to symbolize silversmiths since the middle ages.

Example of a full plate mark of French daguerreotype plate manufacturer CHRISTOFLE.

While the photographer remains unknown, the plate mark offers an interesting glimpse into the world of daguerreotypes, identifying who made the plate and providing clues as to the approximate date of its creation.

For more information about the daguerreotype collection at Library and Archives Canada, check out our Flickr album or listen to our podcast, Mirrors with Memory. To learn more about conservation at LAC, visit our Conservation Wednesdays feature on our Facebook page.

Tania Passafiume is the Head Conservator of Photographic Materials in the Collection Management Division of Library and Archives Canada.

Jennifer Roger is a Curator in the Exhibition and Online Content Division at Library and Archives Canada.