Determining how old a postcard is.
If a postcard is unused, you can still find some clues to its age. Private mailing cards, marked "Mailing Card, Authorized by Act of Congress on May 19, 1898," were used between 1898 and 1901. In 1901, this authorization was discontinued, replaced by undivided back cards that required that one side be used strictly for the address and the other for the picture and any message the sender might care to add. These cards were replaced by divided back cards around 1907, which allowed a message to be written on the left side of the back, with the address on the right. Many of the best cards during this time period were made in Germany, but German cards in America disappeared with the onset of World War I. From about 1916 to 1930, white border cards were the fashion. Around 1930 to 1945, linen cards appeared on a textured, linen stock paper, often with more vivid colors. As early as 1917, photochrome, also known as chrome postcards appeared, and have remained popular to the present time.