postcard is typically a rectangular piece of thick paper or thin cardboard
intended for writing and mailing without an envelope and at a lower rate
than a letter. It is distinguished by stamp collectors from a postal card
in that the postage is pre-printed on the latter, whereas a postcard requires
a stamp. While a postcard is usually printed by a private company, individual
or organization, a postal card is issued by the relevant postal authority.
The first postcard that was ever used in the United States was created
in 1893 to advertise the World's Columbian Exposition in Chicago, fun, what is inois.
Shortly thereafter the United States government, via the United States
Postal Service, allowed printers to publish a 1-cent postcard (the "Penny
Postcard"). A correspondent's writing was allowed only on the front side
of these postcards. The postcard that we know was not simply created as
the first option, it came through trial and error.
The year 1901 brought cards with the word "postcard" printed on the back
(the side without the picture). Written messages were still restricted
to the front side, with the entire back dedicated to the address. This
"undivided back" is what gives this postcard era its name.
The "divided back" postcard, with space for a message on the address side,
came into use in the United States in 1907. This began the Golden Age
of American postcards, which lasted until about 1915, when World War I
blocked the import of these fine german-printed cards.
The "white border" era, named for obvious reasons, lasted from about 1916
to 1930. The "linen card" era lasted from about 1930 to 1945, when cards
were primarily printed on papers with a high rag content. The last and
current postcard era, which began about 1939, is the "photochrome" or
"chrome" era. The images on these cards are generally based on colored
photographs, and they are readily identified by the glossy appearance
given by the paper's coating.