Early history of postcards
The claimed first printed picture postcard.
Austrian postcard from 1901.
Cards with messages had been sporadically created and posted by individuals since the beginning of postal services. The earliest known picture postcard was a hand-painted design on card, posted in Fulham in London by the writer Theodore Hook to himself in 1840, and bearing a penny black stamp. He probably created and posted the card to himself as a practical joke on the postal service, since the image is a caricature of workers in the post office. In 2002 the postcard sold for a record £31,750.
In the United States, the custom of sending through the mail, at letter rate, a picture or blank card stock that held a message, began with a card postmarked in December 1848 containing printed advertising.  The first commercially produced card was created in 1861 by John P. Charlton of Philadelphia, who patented a postal card, and sold the rights to Hymen Lipman, whose postcards, complete with a decorated border, were labeled "Lipman's postal card". These cards had no images.
In Britain, postcards without images were issued by the Post Office in 1870, and were printed with a stamp as part of the design, which was included in the price of purchase. These cards came in two sizes. The larger size was found to be slightly too large for ease of handling, and was soon withdrawn in favour of cards 13mm (½ inch) shorter. The first known printed picture postcard, with an image on one side, was created in France in 1870 at Camp Conlie by Léon Besnardeau (1829–1914). Conlie was a training camp for soldiers in the Franco-Prussian war. The cards had a lithographed design printed on them containing emblematic images of piles of armaments on either side of a scroll topped by the arms of the Duchy of Brittany and the inscription "War of 1870. Camp Conlie. Souvenir of the National Defence. Army of Brittany". While these are certainly the first known picture postcards, there was no space for stamps and no evidence that they were ever posted without envelopes.
In the following year the first known picture postcard in which the image functioned as a souvenir was sent from Vienna.  The first advertising card appeared in 1872 in Great Britain and the first German card appeared in 1874. Cards showing images increased in number during the 1880s. Images of the newly built Eiffel Tower in 1889 and 1890 gave impetus to the postcard, leading to the so-called "golden age" of the picture postcard in years following the mid-1890s. Early postcards often showcased photography of nude women. These were commonly known as French postcards, due to the large number of them produced in France.
Early US postcards
A 1908 postcard of a postcard factory in Chicago, which claims to be 'The largest building in America devoted exclusively to the manufacture of Post Cards'
Back of the above 1905 card
Postcard with 1908 cancellation
American 'divided back' postcard, 1916
The first American postcard was developed in 1873 by the Morgan Envelope Factory of Springfield, Massachusetts. These first postcards depicted the Interstate Industrial Exposition that took place in Chicago. Later in 1873, Post Master John Creswell introduced the first pre-stamped "Postal Cards", often called "penny postcards". Postcards were made because people were looking for an easier way to send quick notes. The first postcard to be printed as a souvenir in the United States was created in 1893 to advertise the World's Columbian Exposition in Chicago.
The Post Office was the only establishment allowed to print postcards, and it held its monopoly until May 19, 1898, when Congress passed the
Private Mailing Card Act, which allowed private publishers and printers to produce postcards. Initially, the United States government prohibited private companies from calling their cards "postcards", so they were known as "souvenir cards". These cards had to be labeled "Private Mailing Cards". This prohibition was rescinded on December 24, 1901, from when private companies could use the word "postcard". Postcards were not allowed to have a divided back and correspondents could only write on the front of the postcard. This was known as the "undivided back" era of postcards. From March 1, 1907 the Post Office allowed private citizens to write on the address side of a postcard. It was on this date that postcards were allowed to have a "divided back".
On these cards the back is divided into two sections: the left section is used for the message and the right for the address. Thus began the Golden Age of American postcards, which peaked in 1910 with the introduction of tariffs on German-printed postcards, and ended by 1915, when World War I ultimately disrupted the printing and import of the fine German-printed cards. The postcard craze between 1907 and 1910 was particularly popular among rural and small-town women in Northern U.S. states.
Postcards, in the form of government postal cards and privately printed souvenir cards, became very popular as a result of the Columbian Exposition, held in Chicago in 1893, after postcards featuring buildings were distributed at the fair. In 1908, more than 677 million postcards were mailed.
The "white border" era, named for borders around the picture area, lasted from about 1916 to 1930.
Mid-20th century US postcards
The Great White Liner "South American," Chicago, Illinois, circa 1915-1930. Curt Teich & Co. postcard 103504.
Mid-century linen postcards were produced in great quantity from 1931 to 1959. Despite the name, linen postcards were not produced on a linen fabric, but used newer printing processes that used an inexpensive card stock with a high rag content, and were then finished with a pattern which resembled linen. The face of the cards is distinguished by a textured cloth appearance which makes them easily recognizable. The reverse of the card is smooth, like earlier postcards. The rag content in the card stock allowed a much more colorful and vibrant image to be printed than the earlier "white border" style. Due to the inexpensive production and bright realistic images they became popular.
One of the better known linen era postcard manufacturers was Curt Teich and Company, who first produced the immensely popular "large letter linen" postcards (among many others). The card design featured a large letter spelling of a state or place with smaller photos inside the letters. The design can still be found in many places today. Other manufacturers include Tichnor and Company, Haynes, Stanley Piltz, E.C Kropp, and the Asheville Postcard Company.
By the late 1920s new colorants had been developed that were very enticing to the printing industry. Though they were best used as dyes to show off their brightness, this proved to be problematic. Where traditional pigment based inks would lie on a paper's surface, these thinner watery dyes had a tendency to be absorbed into a paper's fibers, where it lost its advantage of higher color density, leaving behind a dull blurry finish. To experience the rich colors of dyes light must be able to pass through them to excite their electrons. A partial solution was to combine these dyes with petroleum distillates, leading to faster drying heatset inks. But it was Curt Teich who finally solved the problem by embossing paper with a linen texture before printing. The embossing created more surface area, which allowed the new heatset inks to dry even faster. The quicker drying time allowed these dyes to remain on the paper's surface, thus retaining their superior strength, which give Linens their telltale bright colors. In addition to printing with the usual CYMK colors, a lighter blue was sometimes used to give the images extra punch. Higher speed presses could also accommodate this method, leading to its widespread use. Although first introduced in 1931, their growing popularity was interrupted by the outbreak of war. They were not to be printed in numbers again until the later 1940s, when the war effort ceased consuming most of the country’s resources. Even though the images on linen cards were based on photographs, they contained much handwork of the artists who brought them into production. There is of course nothing new in this; what it notable is that they were to be the last postcards to show any touch of the human hand on them. In their last days, many were published to look more like photo-based chrome cards that began to dominate the market. Textured papers for postcards had been manufactured ever since the turn of the century. But since this procedure was not then a necessary step in aiding card production, its added cost kept the process limited to a handful of publishers. Its original use most likely came from attempts to simulate the texture of canvas, thus relating the postcard to a painted work of fine art.
The United States Postal Service defines a postcard as: rectangular, at least 3 1⁄2 inches (88.9 mm) high × 5 inches (127 mm) long × 0.007 inches (0.178 mm) thick and no more than 4 1⁄4 inches (108 mm) high × 6 inches (152.4 mm) long × 0.016 inches (0.406 mm) thick. However, some postcards have deviated from this (for example, shaped postcards).
A tinted (black-and-white image that has had colored tint added) souvenir card. Image of the Christopher Columbus
taken circa 1896
The last and current postcard era, which began about 1939, is the "chrome" era, however these types of cards did not begin to dominate until about 1950. The images on these cards are generally based on colored photographs, and are readily identified by the glossy appearance given by the paper's coating. 'These still photographs made the invisible visible, the unnoticed noticed, the complex simple and the simple complex. The power of the still photograph forms symbolic structures and make the image a reality', as Elizabeth Edwards wrote in her book: The Tourist Image: Myths and Myth Making in Tourism.
In 1973 the British Post Office introduced a new type of card, PHQ Cards, popular with collectors, especially when they have the appropriate stamp affixed and a first day of issue postmark obtained.