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Wednesday, April 9, 2014

D is for Daguerreotype

Today in the ABCs of Photography:



D is for Daguerreotype

Daguerreotype (də-ˈge-rō-ˌtīp): an early photograph produced on a silver or a silver-covered copper plate; also:  the process of producing such photographs


Daguerreotype of Louis Daguerre in 1844
by Jean-Baptiste Sabatier-Blot. Source
If you have learned anything in the history of photography, you've learned about the daguerreotype. Invented by Louis Daguerre in 1839, this photographic process became the first widely used production, though as time went on, other processes were developed (pun intended) that were far less costly and took less time to shoot and process, as with all technology. Not to mention the daguerreotype was not a negative, and therefore impossible to reproduce*. So don't lose it!

Ever wonder why everyone in old-timey photographs look so miserable? Well, a daguerreotype could well beyond a few minutes to expose! Subjects would have to sit (or stand) as still as possible for such an extended period of time that is was nearly impossible to smile for so long. Can you imagine having to smile for 10 solid minutes? Yikes. Film was not as light sensitive back then, requiring longer exposure times. Much longer exposure times. There were actually methods of holding people in place, from braces to hold the head to sashes tying children to chairs to keep them still. 


From Wikipedia:

"The silver surface is polished with a leather buff using first rotten stone
and then jeweler's rouge and then, by the light of a safelight, exposed to iodine fumes from iodine crystals at room temperature (usually followed by similar exposure tobromine and chlorine), producing a light-sensitive silver halide coating. The plate is then carried to the camera in a light-tight plate holder. Withdrawing the protective dark slide exposes the sensitized surface to the image projected within the dark camera by the lens, creating an invisible latent image on the plate which is then developed to visibility by fuming it with heated mercury. After development, the light sensitivity of the plate is arrested by removing the remaining silver halide with a mild solution of sodium thiosulfate or a hot saturated solution of common salt. To give the image a warmer tone and physically reinforce the powder-like silver particles of which it is composed, a gold chloride
 solution is pooled onto the image and the plate is briefly heated over a flame, then drained, rinsed and dried. Even after this gilding treatment, the image surface is still very delicate and the silver is subject to tarnishing from exposure to the air, so the plate must be kept under glass in a sealed enclosure." (1)



Photo provided by Fred Blake from the Foto Care Rental Department

*Although daguerreotypes are unique images, they could be copied by re-daguerreotyping the original. Copies were also produced by lithography or engraving. Source
(1) Source