The geometry of the bounce: how a single seam rewrote television.
Before optic yellow, the ball vanished against a white background and a black-and-white tube. Then in 1972 the ITF approved a fluoro felt sphere, and the camera finally caught up to the sport — which is also when the sport started designing itself for the camera.
I watched the second set on a fuzzy CRT in a bar in Belgrade last September, and what I noticed first wasn't the rally — it was that the ball, on that old screen, still glowed. Fifty years on, the same felt was doing the same job. A round, vivid wedge of pigment carved out of the teal court, lit from inside by the simple fact of being seen.
The story usually told is brisk: ITF, 1972, white balls were hard to track on television, so the felt got dipped in optic yellow. True, but slim. The harder fact is that the rule didn't just change a ball — it changed where a player stood, how a baseline was painted, how a broadcaster cut between angles, and eventually how every score graphic in this sport learned to crop a circle.