Louis-Jacques-Mandé Daguerre (18 November 1787 - 10 July 1851) was a French artist and scientist who claimed a place in history by inventing the Daguerreotype - the first practical and popular system of photography.
The Le Daguerreotype, a sliding box camera, was the world’s first commercially available camera. Louis Jacques Mandé Daguerre designed the Le Daguerrotype camera to accommodate his Daguerrotype Process. The camera consisted of two wooden boxes, one slightly smaller than the other.
As you can see from this original patent drawing, the smaller box fit tightly inside the larger box. The back of the smaller box had a hinged panel that opened so the photographer could insert a ground glass for focusing which was accomplished by carefully sliding the smaller box in and out slowly until the image was in focus. Once the camera was focused, the photographer removed the ground glass focusing screen and replaced it with the plate holder. Closing the back panel sealing the box from the light, the photographer pulled the protective slide from the plate holder, readying the plate to be exposed.
The sliding box cameras lens, “I” in the above drawing, was a Plano Convex lens achromatic lens with an effective focal length of 415 mm. the lens didn’t have a shutter in the way we think of a shutter. A Plano-convex lens has one flat surface and one convex surface, with the flat surface pointing away from the camera. The camera lens, made by Bianchi, had a brass lens tube fitted over it that was secured to the front of the camera with six brass wood screws. The opening at the end of the lens tube that admitted light had an effective aperture of f-15. A brass cap that acted like a shutter of sorts covered the aperture opening. The Photographer opened it at the beginning of the exposure and rotates it close at the end of the exposure.
The Le Daguerrotype camera was simple in construction but beautiful in appearance.
The Daguerrotype Process
There were five steps in making a finished Daguerrotype picture.
1. The process begins with the preparation of the plate itself. A polished copper plate is plated with silver using either the Sheffield plating or electroplating technique. The silver plated copper plate is then polished to a very high gloss.
2. The highly polished plate is then exposed to iodide vapor in an iodizing box like the one seen here.
3. The plates remain in the iodizing box until the entire surface silver has been converted into silver iodine. When the conversion process is complete, the silver plate is orange in color. The iodizing process sensitizes the plate to light. The iodizing step must be completed shortly before the plate is to be exposed because silver iodine rapidly degrades making the plate useless. Once the plate is ready to be used, it’s installed in a light tight plate holder. This complete process must be carried out in a darkroom.
4. After the exposure, which took as long as 20 minutes in some cases, the plate was returned to the darkroom and suspended over a mercury bath. The liquid mercury bath is heated to 140° F. at this temperature, the mercury vaporizes and bonds with the silver iodine forming an amalgamate.
5. Once fully developed the plate was fixed by placing it in a salt (sodium Chloride) solution. Later the sodium chloride solution was replaced with a sodium thiosulphate solution. The fixer bath washed away all the unexposed silver leaving only the mercury/silver amalgam and the shadows of the original silver.
In 1840, two more steps were added to the process.
1. A Daguerrotype print was very delicate and easily marred so French physicist Hippolyte Fizeau (1819 – 1896) devised a toning technique using heated gold chloride to harden the plate as well as improve it’s appearance.
2. As added protection, the plate was mounted in a sealed glass frame to prevent physical damage and to prevent the plate from tarnishing as silver does when exposed to air.
Major disadvantages to the Daguerrotype process.
1. Because there were no negatives to make copies from, each Daguerrotype had to be originals.
2. Because each Daguerrotype had to be individually exposed, they were very expensive.
3. Because the silver plated copper plates weren’t transparent, they had to be viewed from the camera lens side so the images were reversed from left to right.
4. Because the chemical involved in the Daguerrotyping Process were highly poisonous, it was very dangerous to do. The bromide and mercury vapors were real health hazards.
5. The pictures were hard to view unless they were viewed from just the right angle in good light.
Despite the dangers of working with the bromides and mercury vapors the Daguerreotype photography process continued to be widely used until the late 1850s - particularly in France - until largely replaced by the Ambrotype process or other positive variants of Archer's wet-collodion process, originally a negative process that also replaced the Calotypes.