The 6-cent stamp in tribute to HemisFair '68 was first placed on sale on March 30, 1968, at San Antonio, Texas, where the exposition opened April 6, 1968.
The exposition's theme was "The Confluence of Civilizations in the Americas," and this was echoed in the stamp design by San Francisco artist Louis Macouillard. Macouillard drew a map of the Americas in which curved lines converged on San Antonio. The land areas were pink, the water areas blue, and the lines and denomination were white. The lettering was blue.
The stamp was issued in panes of fifty, with an initial printing of 120 million.
Postal Bulletin (March 14, 1968).