What is a cdv photo?
Those three letters are an acronym for the French carte de visite or visiting card. This style of antique photography took over in popularity from the daguerreotype or ambrotype of the 1840s and 1850s. Though they provided lovely images, the dag and ambro were easily damaged and not suitable to tuck into an album or a letter to a friend.
The Civil War era of the 1860s, however, saw a wide acceptance of the cdv, the invention of either Adolph Disderi in 1854 or Louis Dodero in 1851.
The cdv photograph belongs to the group known as card photographs because the albumen print (a mixture of egg whites, sodium chloride, and silver nitrate) was mounted on paper cards.
The size of a cdv is 2 1/4" x 4 1/4" (although you nay see them sized as 4" x 2 1/2")
The photographer might print, stamp, or emboss his name and town or state on the back (backmark) of the card, below the image, or may omit identification altogether.
The Civil War soldier loved the cdv. These young men would often pose in studios many miles from their home, and obtain images to tuck in with a letter to the folks they left behind, or a sweetheart. 
Cdv photos were cheaper and easier to produce, and required less skill on the part of the photographer. Thus, more of the public, unable to afford the dag or ambro, could afford the cdv image.
Special cdv photograph albums of either leather or celluloid were sold to hold a family's collection, and you can see these albums featured as props in many cdv photos.
Because the subject needed to remain very still for the exposure time, the sitter often supported their head on a stand, rather like an iron floor lamp stem with a U or T shaped holder at the top. You can sometimes see the hint of a head stand base behind the subject's feet, or the frame behind the head, or the brace attached to a posing chair, as noted in this cdv with a gentleman in a top hat leaning on a head stand. 
The earliest cdv images were very simple photos of heads or busts of sitters that became larger in size as time went on, eventually becoming full length portraits.
Also as time went on in the Victorian era, props became more evident, ranging from a simple column or plinth, to the subject seated at a table with a book or album. In the 1880s, props often included more furniture and artificial trees, studio fences, painted murals depicting outdoor scenes or decorated rooms, piles of hay or flowers, and many other folksy creations. Here you see a range in prop styles from a circa 1870 
to a circa 1890 girl with brocade chair, painted mural, and her dog 
Cdvs can be dated in a variety of ways. Sometimes, the sitter signed their name and date on the card! Style of clothing, style of props, style of mount, and presence of a tax stamp (see my Guide on tax stamps on images) can also help you identify the time period that a cdv was taken in.
For more on cdvs, please see my Guide about collecting antique photos.
Ebay carries one of the most exptensive offerings of cdv pictures for sale so browse and enjoy!
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