Cartes de visiteCartes de visite take their name from French “calling cards,” which they were supposedly meant to replace. Measuring 4.5 by 2.5 inches, there were the same size as calling cards but were seldom used as such. Though the process was patented by Andre Adolphe Disderi in Paris in 1854, it did not become popular until 1859.
Process. Cartes de visite were usually produced as albumen prints from wet collodion negatives, but most paper print processes could also be used. A special camera with multiple lenses - as few as four, or more than eight - and a movable plate holder was used to make as many images as possible on a single plate. A contact print was then made, and the individual photographs were cut apart and mounted onto cards. When interest in this small format began to wane, studios introduced larger formats, including cabinet (4.5 x 6.5 inches) and boudoir (5.25 x 8.5 inches).
Identification. Consider the rigidity and thickness of the printed card stock. A border will be present and the corners may be rounded (1870s to 1900) or square (after 1900). Many card photographic prints have the photography studio's information printed on the card. (Hamilton, AARP)
The popularity of card photographs as a format continued into the 20th century, with gelatin and collodion print papers eventually replacing albumen. The backing card stock was often decorated, and people often wrote identifying information directly on the card (Ritzenthaler, et. al., 40-41).
Real-photo postcards (sometimes called RPPCs) are the result of developing a negative onto photo paper with a pre-printed postcard backing. Traditionally, images were printed in black and white on one side, and the other side featured a "Divided Back," where space was reserved for brief message, the recipient’s address, and postage. Later real-photo postcards also featured hand colored images. Subjects ranged from everyday life and street scenes and landmarks to commemorating significant events and historical happenings.
Although photographic postcards could be generated from a variety of photographic processes, Eastman Kodak revolutionized the RPPC format when it began selling Velox photo paper with a pre-printed postcard back in 1902, followed by its "release of the No. 3A Folding Pocket camera, which used film specifically designed for postcard-size prints. Amateur photographers were now able to have their own images printed directly onto postcard paper and send them through the mail" (Collectors Weekly, RPPCs).
Because space on the divided back was generally pre-printed or too expensive to provide additional descriptive information about image, photographers and studio's resorted to hand stamping or embossing RPPCs, or by "exposing [or etching] text directly onto the photograph negative" (Collectors Weekly). One can see the text etched by hand directly onto the photograph negative of the courthouse (left) and the divided back printed postcard (above).
Photochrom (or photochrome) postcards featured a new type of color postcards and became popular after 1939 "when the Union Oil Company began to carry them in their western service stations" (Smithsonian, Postcard History). It is important to note that photochrom postcards are not produced from color photographic negatives, but rather are a type of lithograph. One can discern the visual difference between RPPCs, which shows a smooth gradation of color and form in images, while photochrom postcards reveal tiny dot or ink patterns as a result of the printing process.