Private Mailing Cards: 1898-1901 – The first true postcards were called “private mailing cards”, and were used between 1898 and 1901. They are easily identifiable, as they all are marked, “Private Mailing Card, Authorized by Act of Congress on May 19, 1898”. Correspondence could only be written on the front (picture side) of these cards.
Undivided Back Post Cards: 1901-1907 – Beginning in 1901 the private mailing card authorization inscription was no longer required. Now marked as a “Post Card” on the back, correspondence was still allowed only on the front. As with the Private Mailing Cards, this problem was usually addressed by leaving a little space alongside the image for correspondence. These are called “undivided back” cards to differentiate them from what was to follow…
Divided Back Post Cards: 1907-1914 – Following the lead of other countries, U.S. postcards began to feature a vertical dividing line on the back, the left side for correspondence, the right for the address. For the first time, one entire side of a postcard could be dedicated to an image. Up to this time most cards had been imported from Germany, the leaders in printing technology. But as World War I approached trade with that country ceased, putting an end to this era of interesting, quality cards.
White Border Cards: 1915-1930 – The American-made postcards made during this period usually had a white border surrounding the picture and varied greatly in quality. Simplistic images and garish colors are common, but some excellent postcards still resulted. Be aware that the “linen” cards that followed often had white borders as well, but the woven texture makes them linen cards, not white-border.
Linen Cards: 1931-1945 – Named for their woven fabric-like texture, the colorful linen cards were first introduced by Curt Teich, and are increasingly popular with today’s collectors. It should be noted that the year 1945 is typically said to be the end of the linen era, but they were in fact produced, in ever-dwindling numbers, throughout the 1950s.
Chrome Postcards: 1939-today – Photochrome postcards, usually just called “chromes”, were first introduced in 1939. The production of linen and chrome cards overlapped for a number of years, but chromes had completely taken over by the late ’50s. Their shiny gloss makes chromes easily identifiable. Most collectors have yet to fully embrace the chrome cards, but that’s sure to change in time.