Sometimes, the results were mixed — not unexpected, coming off baseball’s longstanding adherence to traditional aesthetics — but that was just fine by me. My formative years coincided with the opening of modern, multipurpose stadiums, color TV, and a new approach to what sports could look like, played by athletes with long hair and flamboyant mustaches. While any number of the uniforms were considered ugly by contemporary standards, they also projected a sense of optimism and a fresh take on a very visible and vital aspect of American popular culture.

New synthetic fabrics allowed for a far more expressive range of hues. As professional sports expanded to America’s Sun Belt, it welcomed new markets and new fans who were untethered to visual traditions that, in some cases, dated back to the years immediately following the Civil War. The Cincinnati Reds’ identity, for example, is tied to that of the original Cincinnati Red Stockings, whose roots date to 1866.

Professional leagues like the World Hockey Association, the American Basketball Association and the World Football League broke free from tradition. In 1974, the W.F.L. kicked off its inaugural season with yellow footballs, and one team— the Southern California Sun— took the field in magenta uniforms.

For me, though, the uniforms of Major League Baseball in this era were the greatest.

Take a look at images of the 1977 M.L.B. All-Star Game to see this period in all its chromatic glory. Yes, some players are clad in the traditional home whites and road grays, but scattered among them are uniforms in glorious powder blue, black, orange, red, yellow and brown — as well as one in rainbow.