[Note: Your comments and corrections are very welcome!]

Below are some brief tips for correctly identifying some of the antique photographs most commonly found for sale on eBay, along with a bit of history and some valuable information about the cases that housed many of them. (Guide revised with new information and photos, July 9th, 2007.)

Daguerreotypes are unmistakeable. They were made on silver-plated copper sheets so they reflect just like mirrors. Any photograph cased behind glass is going to be shiny and reflect light, and this effect doubtless leads to many misidentifications on ebay, but Daguerreotypes are not merely shiny; they actually reflect images as clearly as any hand mirror does.

Note the clear reflection
of my hand and camera.

Daguerreotypes are widely regarded as the most detailed and the most beautiful of all photographs. The life-like clarity of a well-focused Daguerreotype is astonishing. Daguerreotypes were sealed behind sheets of glass and cased to prevent tarnishing. The seals used included tape, paper and glue, and wax; often at least remnants of these original seals remain. They are non-magnetic, and when viewed at some angles, the images disappear. Daguerreotypes should be handled with care as the silver surfaces can scratch easily. A casual wipe with a thumb to remove dust, for example, can leave scratches that can never be removed without also destroying the image.

Daguerreotypes were invented in 1837 by Louis-Jacques-Mandé Daguerre and revealed to the world in 1839 when the French government gave him a lifetime pension in exchange for his agreement to not patent them. (There is more information below.) Daguerre had already patented them in England and Wales, only days before the French government's grant, and he apparently felt he was under no obligation to cancel those patents, so early English Daguerreotypes were generally only made by a few licensed studios. In the United States and the rest of Europe, however, the new technology, unhindered by patent law, spread rapidly. Within a few years, thousands of photographers had set up studios throughout the United States. The popularity of the Daguerreotype began to wane within about fifteen years, for reasons that included, among others, the expense of the silver-plating, the use of mercury in the process, exposure times of at least thirty seconds, and their inability to be reproduced (they are direct positives, so there is no negative to make reproductions), so as other processes were invented, photographers began to use the newer technologies. Daguerreotypes were essentially no longer commercially produced by about 1860.

This Daguerreotype is so clear
and well made that individual hairs
can easily be seen on the original.

A reproducible paper process, called the calotype, was invented in England in 1839 by William Henry Fox Talbot. He continued to improved this process, also known as the salted print process, for a number of years, but calotypes never developed wide popularity. Talbot's process sensitized the paper itself, not the paper's surfaces, so images were formed within the structure of the paper, causing them to lack the intense clarity of a well-made Daguerreotype, even with long exposures. Additionally, Talbot held his own patents at first, rather than releasing them to all, so early salted paper prints are very rare. Still, for many years this was the only process that was easily reproduced.

In the 1850s, several collodion processes were invented, the first by Frederick Scott Archer in 1851. Collodion is guncotton dissolved in ether and alcohol, and because it is both clear and sticky, it makes a highly effective binder. Archer was seeking a way to make a better negative than Talbot's salted paper process could make. His resulting wet plate process became the foundation of photography for the next couple of decades. Archer's process was widely adapted and modified, but the basics remained the same: A glass plate was coated with collodion, which was then sensitized to light by treating it with silver nitrate. The plate was next exposed in the camera while it was still wet, then quickly developed in a cyanide mixture(!), washed in distilled water, then carefully varnished. The various collodion processes had the advantages of requiring significantly shorter exposure times; using less expensive materials; producing images that weren't mirrorlike, making them easier to see; and of being easily reproduced. They quickly became popular with sitters and photographers alike.

The most commonly known collodion process, the Ambrotype, was patented in the United States by James Ambrose Cutting in 1854. His process differed very little from Archer's, but he realized that, in addition to the paper prints the wet plate process negative was designed to produce, the negative itself could also be sold to the customer, satisfying the still common desire for a cased image. He achieved this by slightly underexposing his negatives, then bleaching them. He next glued a piece of clear glass over the collodion side of the negative to protect it from being scratched off. (Today, the effects of the balsam based glue he used can be seen in the "snowflakes" sometimes appearing between the glass sheets.) He next had to place the image over a black background to create the illusion of being a positive, and designed cases specifically for this purpose that suspended the image between two black velvet lined covers (much like the front and back covers of a book). Since both covers could be opened, the viewer could see the image from both directions, eliminating the image reversal generally found in photographs of the day (see below).

This early Ambrotype by Mathew B. Brady
is housed in one of Cutting's two-way cases.

The same Ambrotype as above with half against
a dark background and half against a light background
demonstrates that Ambrotypes really are negatives.

Other photographers quickly latched onto Cutting's idea, but soon many had simplified the process to use the already existing Daguerreotype cases and, as usual, cheaper materials. Usually a piece of black felt was placed behind the photo, often glued to a piece of cardstock; at other times black lacquer was painted directly on the glass; and sometimes a sheet of black-painted metal was used. Some of the more careful photographers enhanced their Ambrotypes by meticulously scratching away portions of the image that were meant to appear black, allowing the black backing material to show through clearly. The glass that sandwiched and protected the collodion side of the image was often omitted, to save money. These unsealed Ambrotypes are subject to chipping, peeling, and scratching, and should be handled with great care. Once the image has been wiped away, it is gone forever.

In a variation of this latter technique called the relievo, the Ambrotype's background was scraped away, then the image was backed by a light-colored surface, rather than a dark, that had been spaced from the image by a piece of glass or other method; this created a three-dimensional effect. So-called ruby and amethyst ambrotypes were made on glass of those colors, and no black backing was required.

 
The entire back of this sealed Ambrotype is lacquered black.
Daguerreotype seals are essentially identical.

In Europe, Ambrotypes were commonly called amphitypes, but this was technically a misnomer. True amphitypes were made on glass (they were originally made on paper), but albumen (egg white), rather than collodion, was used as the binder, and the process never proved successful.

Another "type" often mistaken for an Ambrotype is the opalotype, in which the image is fixed to opal glass (referred to today as milk glass) through a variety of methods, including carbon-gelatin transfer and gelatin-bromide emulsion. Similarly, ivorytypes occassionally (but rarely) turn up on eBay; these images are usually hand tinted salt prints, or collodion or albumen prints, that have been fixed to glass with wax, which makes them more-or-less translucent, with a white backing added to the opposite side.

Ambrotypes were popular for only about ten years, and were eventually superceded by the Melainotype, another collodion process invented by Peter Neff at about the same time as the Ambrotype. Melainotypes, also known as ferrotypes, were first made on heavy iron, but subsequent advancements demonstrated they could be just as easily made on cheaper and thinner sheets. Commonly called tintypes (although tin was not used), ferrotypes became the most popular process by 1860, largely because they were cheaper. Another advantage to the tintype was its versatility of shape and its durability. Tintypes could be more easily cut into unusual shapes and sizes, were more difficult to damage, did not require sealing behind glass, and could be cased in paper sleeves to fit into the newly popular photograph albums. Like Daguerreotypes, tintypes were made on the front of the metal plate, but unlike Daguerreotypes, they appear almost as if they had been glued or lacquered onto the surface (which, essentially, they were).

Like Daguerreotypes and Ambrotypes, tintypes are also found cased, with or without glass, so a quick test to differentiate a tintype is to simply apply a magnet to the cased image. Bear in mind that some Ambrotypes used black-painted magnetic metal as a backing, so this is not a foolproof test. I have seen on eBay that some buyers ask sellers if a purported Daguerreotype has a copper-colored back side. Clearly this question is asked to determine if a copper sheet has been used, but I have seen many tintypes painted with a bronze-ish or coppery finish on the backs, presumably to deter rust, so don't rely on that only.

The true copper back of a Daguerreotype (l)
vs. a copper- or bronze-colored back of a tintype (r).

Similarly, I have seen a few Daguerreotypes with silver or a silvery finish on the non-photographic side, leaving no copper visible. Ambrotypes with the black-painted metal backing also often have a silvery side as well.

The black metal backing (t) of some Ambrotypes
can have a silvery face on the outside (b).

In short, coppery should not be confused with copper, and silvery should not be confused with silver. Tintypes are the only photographic type that can rust, and they can also peel and chip, but in general they are very durable.

An extreme example of
the flaking tintypes can suffer.

In about 1860, the carte-de-visite (CDV), a paper albumen photo mounted on a 4.5 x 2.5 -inch piece of cardstock, became very popular in the US, but their popularity waned shortly after the war to be supplanted by the cabinet photo (AKA cabinet card), which was essentially a bigger (6.75 x 4.5 inches) version of the same, albeit on thicker and more ornately trimmed cardstock. Albumen photos differ from salted paper prints in that the photo is on the paper rather than in it. They appear sharp and glossy, often to this day, and have surprising durability. It is not uncommon to see cabinet cards from the 1870s and 1880s that look almost as if they had only just been printed. (Beware fakes! Modern reprints can usually be identified with a hand lens: There should be none of the dots associated with a modern printing process.) CDVs and cabinet cards eventually supplanted the earlier photographic types, which ended the photographic case industry as well, but there was enough overlap that occasional photographers would continue to make older styled photographs many years after their heyday had passed. Itinerant photographers, especially, continued to make tintypes into the 1920s, and we have in our collection an English Ambrotype with a lacquered back of a young woman that is clearly from the 1890s.

***********

Photographic cases were first made the way cases had long been made for painted portrait miniatures. Typically they consisted of a wooden frame covered with leather, sometimes plain, sometimes lightly embossed or gilded. Over time, the decorative stamping on the leather became more ornate. Some were hand-painted. Other coverings were introduced, including papier mâché, lacquer, velvet, tortoise shell, and mother of pearl, and the cases became ever more elaborate and a significant part of the sale of a photograph. A few were made with metal, such as the Halvorson case.

The gold-colored mat and foil preserver usually found around cased images are made of an alloy of copper and zinc called Pinchbeck after its inventor, Christopher Pinchbeck.

The bijou ("jewel") case was made to look like a book.
This one was crafted from lacquered and painted wood
and decorated with mother of pearl and silver wire.

In the 1850s a newly invented thermoplastic made from shellac and finely ground sawdust gained in popularity because cases made from it could be elaborately engraved and die-pressed. This material was called Composition or Union, depending on whose competing patent was used, and the cases themselves became known as Union cases. (This name has nothing to do with the Civil War!)

A thermoplastic Union case.

It is important to note that Union cases never replaced the cases made from leather or other materials, but were rather just a different type of case, so one cannot look at a leather case and say it is an early case simply because it is made of leather. Also there really is no such thing as a transition case; cases made from both leather and thermoplastic were just cases made from both leather and thermoplastic.

Lastly, despite common belief and eBay mythology, gutta percha was never used for photographic cases.

***********

The plate sizes referred to in eBay listings reflect the decision made by Daguerre, sometime during his experiments with fixing the images produced by the camera obscura, to use plates sized 6.5 inches by 8.5 inches. I do not know why he so decided, but if I were to guess, he did so because that size was convenient for some reason: perhaps it simply matched the dimensions of the camera obscura he was using; perhaps he did so because it mated with work he had earlier done with Joseph Nicephore Niépce, the man who in 1827 took the first successful photograph after an eight-hour exposure. Someone probably knows the true reasons, but I don't.

Niépce worked with Daguerre, a successful artist, to try to make his cumbersome process and rather ugly photographs more artistic; Daguerre, for his part, was interested in using photography as a way of making painting more accurate. Niépce died only four years later, in 1833, with the two having had little success in their experiments. Daguerre refused to give up, however, and accidentally produced the forerunner of the Daguerreotype in 1835 when he stored one of his exposed plates in a cabinet that also contained a broken thermometer. When he looked at the plate later and saw an image, he realized the mercury fumes from the thermometer must have somehow contributed. This started him along a new route of research whereby he was able to produce fixed images successfully by 1837, and was ready to report his success in January of 1839.

Photographers who read Daguerre's full report released in August 1839 followed his specifications exactly, including his size specifications, and thus the concept of the whole plate was born. For reasons most likely related to cost, plates were cut up into different sizes, and the easiest way to do so was by simple repeated bisecting (or trisecting). Cases were manufactured to match these new standardized sizes, first by the photographers themselves, then by companies that were already manufacturing cases for other products.

The approximate sizes of the images (measure the actual image, not the case) are:

Whole plate: 6 1/2" x 8 1/2"
Half-plate: 4 1/4" x 5 1/2 "
Quarter-plate: 3 1/4" x 4 1/4"
Sixth-plate (the most common size): 2 3/4" x 3 1/4"
Ninth-plate: 2" x 2 1/2 "
Sixteenth-plate: 1 3/8" x 1 5/8"
These size traditions carried over into all cased images, including ambrotypes and ferrotypes (tintypes).

(Note: Because additional lenses, mirrors, or prisms reduced the amount of light that made it to the negative, photographers kept cameras quite simple throughout much of the nineteenth century, and because light rays passing through a single lens are both reversed and inverted, period photographs are almost always reversed, as if they had been photographed in a mirror.)

***********

For this information, I am indebted to a number of sources and authors, most notably (and in alphabetical order) Paul K. Berg, author of Nineteenth Century Photographic Cases and Wall Frames; John S. Craig, author of Craig's Daguerreian Registry; Clifford & Michele Krainik, authors (with Carl Walvoord) of Union Cases: A Collector's Guide to the Art of America's First Plastics; Dr. Robert Leggat, author of the web site A History of Photography from its beginnings till the 1920s; William E. Leyshon, author of Photographs from the 19th Century: A Process Identification Guide; and the Daguerreian Society. (I apologize, but eBay won't let me post external links; please take the time to look them up, as they are all worth it.) Thanks to all of you for making this passion understandable and fun!

Steve Hight