The 6-cent postage stamp marking the 100th anniversary of professional baseball was issued on September 24, 1969, at Cincinnati, Ohio.
Alex Ross of Ridgefield, Connecticut, designed the stamp, which was printed in four colors by three passes on the presses. It depicted a player in white uniform, red cap, and black sweat shirt. The foreground was green and the background yellow. The inscription was black. Yellow and green was the first offset pass; red and black the second. An additional black was applied by the RCA press.
The stamp was issued in panes of fifty, with an initial printing of 120 million.
Postal Bulletin (August 28, 1969).