In 1972 the US Postal Service commissioned pop artist Robert Indiana to turn his painting of the word 'Love', created for the Museum of Modern Art's 1965 Christmas card, into a postage stamp. It was released in Philadelphia, the "City of Brotherly Love," on January 26, 1973, in time for Valentine's Day.
The Postal Service's Office of Philatelic Affairs was flooded with complimentary letters and, when the first-class postage rate rose to ten cents in 1974, it received numerous suggestions to reissue the stamp at the new denomination. But not everyone loved the Love stamp. One postal customer dubbed it the 'Hippie Stamp'; another suggested that it resembled "something concocted on a hashish couch.'
The 8-cent stamp paid the domestic first-class letter rate. It was printed in red, green, and violet blue ink on the Andreotti press in sheets of 200. These were further divided into four panes containing fifty stamps each for shipment to post offices. The art director for the stamp was Bradbury Thompson.
The Postal Service did not call this issue a 'Love' stamp, instead titling it "A Special Stamp for Someone Special." Another stamp featuring the word 'Love' was not issued until 1982, initiating a series that continues today.
Reference: National Postal Museum Library, Papers of the Third Assistant Postmaster General and successor agencies, Stamp Design Files, Folder for Scott #1475.