Image on Glass
Dating ambrotype photographs is fairly easy for genealogists. It is a cased image like the daguerreotype, but it was short-lived. The ambrotype was only in popular production for about ten years. So, if this is part of your genealogy puzzle, you can be sure it was produced between 1855 and about 1865.
The ambrotype's life span was very short, wide-spread use was less than ten years, but produced a vast collection of beautiful images. While the name ambrotype was derived from the Greek word ambro, meaning imperishable, it was still a delicate, easily damaged photograph. One advantage it did possess over the silver daguerreotype was that it did not tarnish.
The ambrotype photograph was made by coating a piece of glass with a silver solution and exposing this to the image. The image is sometimes on the back of a glass plate and is sandwiched with another glass behind it. This was typical of early examples.
Later images were developed on the front of a single plate of glass. The back of the glass was coated with a black lacquer or backed with black paper or cloth. This allowed the negative-looking bare image to appear as a positive.
The ambrotype was packaged in the same manner as the daguerreotype, encased with a mat, top glass, and preserver; and then placed in a case.
Is My Image an Ambrotype?
Identifying an ambrotype is fairly easy. While the ambrotype is typically cased like a daguerreotype, it does not exhibit the same look. It does not pass the mirror test. Rotating the image will not cause the image to reflect like a mirror or look like a negative. Note: Don't mistake the reflection of the cover glass to be the mirror look.
If the image is out of the case, you will be able to confirm the nature of the photograph. The ambrotype is developed directly on a plate of glass, not on silver-coated copper plate like the daguerreotype or the blackened-iron of the tintype.
SPECIAL NOTE: Do not try to clean the face (or image side) of an ambrotype. Even the softest camera lens brush will scratch the delicate surface. At best use compressed air to remove loose dust or particles. See the Restoration section for more.
Components of an Ambrotype
Photographers used many of the same pieces and methods for packaging an ambrotype as they did for the daguerreotype (see Daguerreotype page). Nearly all ambrotypes will have a preserver (if the packaging is original). This and other characteristics will help you in dating ambrotypes.
Observable Characteristics
Mat Characteristics - Simple to Ornate
Mats, the brass inner frame that laid on top of the glass, experienced design evolutions that are datable. Smooth or finely textured surfaces adorned mats up to about 1859. These may have included some very simple etching. Then, intricate designs began appearing, stamped into very thin mats. These are found until the demise of the ambrotype.
Preserver - Simple to Intricate
Along with mat designs becoming more ornate, the preserver also became more intricate, and delicate. Preservers before 1859 were usually plain along the edges, with a singular and simple design. From 1859 onward, the preserver exhibited elaborate designs, with bulges at the corners and in the middle of the edges.
Glass Types
There are three different glass examples in the ambrotype.
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Early images used two pieces of glass glued together. The image was sandwiched between them. This technique was used from 1855 to about 1857.
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A single pane of glass was used almost exclusively from about 1858.
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Ruby-colored glass was used (dark green also, but is very rare) beginning about 1858. This eliminated the need to have a dark backing.
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