Daguerreotypes were exquisitely detailed, but the only way to make a copy was to take another daguerreotype of the daguerreotype.

Frederick Scott Archer

In 1851, Frederick Scott Archer discovered a way to create negative images on glass plates. It was a wet, messy process using flammable materials, but once dried, the image was permanent. The negatives could then be used to make an infinite number of paper prints, which were almost as detailed as daguerreotypes.

When a black background is placed behind an ambrotype negative, it appears as a positive image.

At first, though, photographers took those glass plate negatives and placed them in the same kind of cases that had been used for daguerreotypes. A photograph in a case was what people were used to! These cased negatives were called Ambrotypes after their inventor.

Against a black background, the negatives look just like daguerreotypes… or do they? Cased photographs have tricked historians into thinking that a less valuable ambrotype is a rarer daguerreotype.


Moses Asbury Hill | Photographer/date/location unknown | Norwalk Public Library History Room C.P. PH-4843
Sarah J. Hill and Elizabeth Haton | Photographer/date/location unknown | Norwalk Public Library History Room C.P. PH-4941

Daguerreotypes are exquisitely detailed with a great range of tones from white to black. The metal backing is highly polished so that it reflects almost as well as a mirror.

In an ambrotype, the image is suspended in an emulsion on the surface of glass. The negative image looks positive against a black background. Ambrotypes are darker, their tones more muted.

Which is the daguerreotype? Which is the ambrotype?