Essentially the RPPC has a photograph on one side and a postcard back.
These postcards might be commissioned by the shopkeeper, perhaps from an image which they supplied, or they might simply be bought wholesale from a listing.In 1901 the manufacturers of private mailing cards were allowed to use the term "Post Card".Many manufacturers tried to leave some white space so the sender could add a written message. In 1907, Congress allowed the back to be divided so that the sender could write a message on the left side of the back and the address to whom the post card was to be sent on the right side. These were generic post cards, blank on one side where the sender could write a message and printed postage on the other side with space for a mailing address.They were often called "Private Mailing Cards" or "Private Cards".RPPCs might have been published by postcard publishers who operated nationally, regionally or locally.Sometimes these are clearly marked with the publisher's details, sometimes not.The camera, designed for postcard-size film, allowed the general public to take photographs and have them printed on postcard backs, usually in the same dimensions (3-1/2" x 5-1/2") as standard vintage postcards.Many other cameras were used, some of which used glass photographic plates that produced images that had to be cropped in order to fit the postcard format.Realtors used them to sell new housing by writing descriptions and prices on the back.Real photo postcards became expressions of pride in home and community, and were also sold as souvenirs in local drug stores and stationery shops." On March 1, 1907, Federal legislation permitted senders, for the first time, to include a message on a portion of the back of a postcard.