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Daguerreotype

(Fr.: daguerréotype)

(1839- ca. 1860) The first practical photographic process, invented by Louis Jacques Mandé Daguerre in the late 1830s. It was put into the public domain by the French government on August 19, 1839. At first, the process required exposures of 20 to 30 minutes. Optical improvements, introduced by Lerebours, in May 1840, reduced exposures to two minutes. Chemical improvements by Antoine Claudet and others shortened exposures in bright sunlight to a fraction of a second for a small 1/6 plate (7 x 8.3 cm) in 1841.

Identification: The daguerreotype is a copper plate coated with a highly polished silver surface, made sensitive to light by fumes of iodine, exposed in a camera, and developed by mercury vapor. The image is in fact negative but appears positive when viewed at the proper angle. The daguerreotype image is exceedingly fragile and for this reason is always found under glass in a protective case. The majority of "dags" are rectangular in shape and vary in size from "whole plate" (216 x 165 mm) to half plate, quarter plate, etc. The specimen in a locket is very unusual.

Conservation: Attempts by non-specialists to remove tarnishing with any silver cleaning solution should be avoided as cleaned images tend to tarnish considerably faster and the value of the photograph will be reduced. Ordinary cleaning solutions also remove parts of the image, i.e., silver, gold and mercury. (Nadeau, Encyclopedia, p. xxx).

Daguerreotype2w8x6e This daguerreotype (ca. 1845) was recently purchased in Montréal, Québec. Both the sitter and the photographer are unknown. The inscription on the back says "father." The daguerreotype is 40 mm x 33 mm. The outside dimensions of the locket are 63 mm x 50 mm. The locket came in an egg shape wooden case covered with a thin red leather. We welcome any information that might help us determine the origin of this beautiful specimen.

This daguerreotype (ca. 1845) was recently purchased in Montréal, Québec. Both the sitter and the photographer are unknown. The inscription on the back says "father." The daguerreotype is 40 mm x 33 mm. The outside dimensions of the locket are 63 mm x 50 mm. The locket came in an egg shape wooden case covered with a thin red leather. We welcome any information that might help us determine the origin of this beautiful specimen.