News From Terre Haute, Indiana

February 1, 2014

GENEALOGY: Glass ambrotype plays role in dating photos

Tamie Dehler
Special to the Tribune-Star

TERRE HAUTE — Last week I began a discussion of the oldest photographs, all of which were produced as encased images. The daguerreotype was the earliest of these: it was a positive photographic image on a copper plate, produced from 1839 to the early 1860s, and was most popular from 1842 to 1858.

The ambrotype is the second kind of photographic image that you may find in a case. In the early 1850s, the “wet collodion” process was developed and began to be used to create glass photographs around 1854. Essentially this procedure involved coating a piece of glass with chemicals, putting the glass in the camera while still wet and exposing it to light in front of an image. The resulting picture was called an ambrotype.

These were negative images. To make them appear positive, a piece of black cloth or paper was placed behind the image, or black shellac was applied to the back of the glass. The resulting image was reversed, however, and represented what the person would look like in front of a mirror.

Ambrotypes were very delicate images and had to be protected. For that reason, they were placed in cases. Early ambrotypes often had another piece of glass placed behind the glass negative, to sandwich the image and further protect it. A glass cover was placed on top, followed by a brass mat that framed the image in an oval or another shape, then a brass “preserver” — a kind of supportive frame — was placed around the entire assembly. This assembly was then placed into the case. The case had a lid that was on hinges and latched. The inside of the lid was lined with cloth, such as velvet.

Ambrotypes tended to lack contrast and were, therefore, sometimes hand-painted to bring out more features of the image. Typically, the cheeks of the individual in the portrait were tinted pink, and then clothing accessories such as buttons, sashes, bows, watch chains and lockets were accented.

Around 1858, photographers began to utilize colored glass — red, green or purple — for some ambrotypes. This darker glass eliminated the need to use a black backing for the image. Colored glass is relatively rare, but ruby ambrotypes were the most common.

Dating the glass image: Ambrotypes were popular for a relatively brief period, from 1854 to 1866. While it is definitely not recommended to take apart a cased image, ambrotypes can be dated by the glass image itself. If the image (emulsion side) is on the back of the glass plate with another piece of glass behind it for protection, it is an earlier image. If the emulsion side is on the front of the glass plate, varnished for protection, it is a later image. If it is on colored glass, it is 1858 or later. If you have an exposed image, remember that it is extremely delicate. Never attempt to clean it.

Dating the mat: A simple, smooth, or granularly textured brass mat indicates an earlier ambrotype. After 1859, brass mats began to be adorned and engraved with many complex and ornate designs.

Dating the preserver: Early brass preservers were of simpler design, thicker and heavier. Later preservers were thinner, more delicate-looking — but actually stronger in construction — and with more intricate designs.

Dating the case: Cases were discussed in detail last week. Essentially, they could be papier mâché, leather-covered wood or “thermoplastic.” The last was also called a “union” case. It was hard like plastic, molded — often with more complex embellishments — and sometimes dyed different colors. It was introduced in 1854.

View ambrotypes online at www.loc.gov/pictures/ search/?q=Ambrotypes%20and%20lc%20dig&st=grid and www.phototree.com/ gallery.asp?cat=amb&f0=Ambrotypes.

— Next week: tintypes.