Daguerreotype

A daguerreotype is an early photograph made directly on a polished metal plate, usually silver-plated copper. The process was introduced in France in 1839. No separate camera negative is made for producing a series of paper prints.

The reflective surface is an important identifying feature. Depending on lighting and viewing angle, the image can appear positive or negative. A photograph that looks dark straight on is therefore not necessarily damaged. Examine it carefully through its protective glass without touching the plate.

A case does not automatically identify a daguerreotype

Ambrotypes on glass and tintypes on iron could also come in small cases. Nor does a brown-toned old paper portrait become a daguerreotype merely through its appearance. Distinguish process from subject, housing and later reproductions.

Protect the surface

The image surface is extremely vulnerable. Fingerprints and even soft brushes can cause damage. Do not use silver polish, cloths or ordinary glass cleaner on the plate, or open a sealed package to obtain a clearer view.

Conservators at the National Galleries of Scotland also describe how deteriorating cover glass can damage the image beneath. Haze or droplets inside the housing therefore need professional assessment rather than treatment as ordinary dirt.

Practical example: record the portrait together with its case, inscriptions and known family history. To offer it for sale, send OBA photographs of the whole object and its documentation.