Birth certificates show that you were born. Death certificates show that you died. Photographs
show that you lived."
This unattributed quote seems custom-made for today's photo-crazed culture. Cell phone cameras are ubiquitous; over ninety-one
percent of North American adults are armed with one. Photos are so cheap and easy to acquire that over three-hundred-fifty
million of them are uploaded to Facebook every day.
There was a time, though, when making a photographic image was a slow and expensive procedure. The first chemical process
for photography (1725) required an exposure time of up to eight hours. There were few improvements in that technique over
the next one-hundred years. In 1826 Joseph Niepce created fuzzy images with a process called "heliography". In1837, Louis
Daguerre developed the first commercially viable photographic process using a technique similar to that of Niepce. Daguerre's
early "daguerreotypes" produced sharp, clear images with an exposure time of only ten to twenty minutes. Further refinements
were later made that shortened the exposure time to under a minute.
Daguerreotypes are an ideal collectible antique: they are typically one-of-a-kind images, rare (out of common usage since
about 1855), tough to create, and difficult to convincingly fake. They are easy to store, transport, and display. There
is also an active market for them: as of this writing, eBay lists 1,432 in-progress auctions for the search term "daguerreotype".
Actual prices achieved in the past thirty days range from $23,550 to under $10. In 2004, Cowan's Auction sold an 1856 Robert
Vance whole-plate daguerreotype of San Francisco for $143,750. One-of-a-kind daguerreotypes of famous people or events are
particularly valuable.
Of course, the lower-priced eBay sales were likely damaged, faked, or mis-attributed daguerreotypes. But with a price range
spanning more than $134,000, it's important to know how to identify authentic items. Mistakes can be costly, but a trained
eye might find an undervalued treasure.
The key to learning how to identify daguerreotypes is to understand how they were made, how they become damaged, and how
they can be faked.
Let's begin with the process. Daguerreotypes are positive, laterally-reversed images created when silver halides are exposed
to light. Unlike 20th-Century film photography, there are no "negatives" that must be developed to obtain a "positive" image.
Halides are generated by alternately exposing highly polished silver or silver-clad copper plates to iodine and bromine
fumes. What's important to note is that the halides do not permanently attach to a plate's surface; they only stick to it.
After the halides are fully exposed to the light emanating from a camera lens, a plate is placed in a mercury vapor chamber
to develop the image. Next, a plate is dipped in salt-water to wash away any unexposed halides then washed again with distilled
water. In some cases, an image can be further enhanced by gilding with a gold chloride solution.
Because silver tarnishes, daguerreotype images darken over time. Because the halides do not embed into a plate, images cannot
be polished to remove tarnish; doing so would remove the image. To retard the darkening process, fragile daguerreotypes
were placed into glass-covered hinged frames. A frame's back was sealed with paper to keep out air. Sometimes, nitrogen
was introduced into a sealed frame to further protect an image.
Caution is advised when buying daguerreotypes online; some eBay sellers confuse daguerreotypes with two other mid-19th Century
photography products: tintypes and ambrotypes. Tintypes are made on emulsion-coated tin and are usually business-card size.
Ambrotypes have a photosensitive emulsion coated onto glass. Both tintypes and ambrotypes are painted black on the back
surface of the plate, and neither exhibits the shiny surface of a daguerreotype.
Characteristics of authentic daguerreotypes are as follows:
- A full-size daguerreotype plate is 6.5" x 8.5". Plates also come in half-size (4.25" x 5.5"), quarter-size (3.25" x
4.25"), sixth (2.75" x 3.25"), ninth (2" x 2.5"), and sixteenth (1.27" x 1.6"). The most common size is a sixth. These sizes
do not include frame and matting.
- Exposed halides reflect light differently than does a plate's polished silver surface, which is what causes an image
to appear on the plate. Images can only be seen from one angle; when a daguerreotype is turned it reflects light differently
and the image disappears.
- Images will tarnish where they have been handled and where they have been exposed to air or contaminates. Examine frames
for gaps if tarnish is noticed around the edges of an image.
Daguerreotypes are extremely sensitive; once created, the image surface cannot be touched. Damage must be addressed immediately,
otherwise it becomes permanent with no means of recovery. Common damages include:
- Careless framing that initiates fingerprint stains which manifest years later
- Tarnishing from humidity, dust, or air resulting from the frame backing paper coming off
- Aging and decomposition of a frame's antique glass, or breaking of the same
Historic daguerreotypes can be forged, but the process is difficult. Even when forgers possess the equipment and skills
to replicate the daguerreotype process, obtaining an image that isn't in print elsewhere can be problematic. When a daguerreotype
process is used, there are only two ways to catch the deceit: disassemble the frame and inspect the plate (which isn't a
good idea) or photograph the framed image and search online to see if the image is available in another format.
Less talented con artists may photocopy a daguerreotype, modify it with Photoshop, print it, seal it in a period-style frame,
and sell it as a 19th-Century original. Amateur collectors will seldom disassemble a frame for close inspection of the image,
fearing that they may ruin an authentic daguerreotype. Such fakes are easy to spot because (unlike a real daguerreotype)
the image can still be seen when it is viewed at different angles.
As with any collectible, knowledge is a buyer's best defense against fraud. With that in mind, enthusiasts are encouraged
to begin a reference library. The following books and websites are recommended: