There are no films or negatives in the Daguerreotype process; it is a “direct-positive” process—that is, light and dark appear to mirror reality on the image. The background surface is a thin copper sheet or plate. This is how the photographic magic happens.
The copper plate is prepared with a thin coat of silver and highly polished, like a mirror.
To make the surface light sensitive, or photosensitive, it is then tempered with iodine fumes. This iodine treatment gives the plate a rose-gold color.
The iodized copper plate is transferred in a lightproof container and carefully positioned in the back of the camera.
The subject is posed in good lighting. Subjects are often propped up from behind to help them not move. The lens cap is not taken off until the subject is ready.
The picture is taken. With improved lenses, the exposure time is reduced to 15–30 minutes for a half-plate or whole-plate, and 10–90 seconds for a ninth-plate or sixth-plate.
The image is developed by putting the plate in a fuming box filled with mercury vapors. The mercury reacts with the silver coating, making the image appear on the plate.
To fix the image, or make it permanent, the plate is washed three times. First, in sodium thiosulfate (a salt bath), second in gold chloride for toning, and third in distilled water for cleaning.
Once dry, the photographer may choose to color the image by hand. Any coloration is done with a fine tip brush and powdered pigment.
Presentation of the Daguerreotype portrait is important. Each Daguerreotype is unique. Most often, a finished portrait is matted, protected under glass, and placed in a decorative metal frame.
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