when did tennis balls changed from white to yellow
Tennis ball Modern tennis balls must conform to certain criteria for size, weight, deformation, and bounce criteria to be approved for regulation play. The International Tennis Federation (ITF) defines the official diameter as 6.54–6.86 cm (2.57–2.70 inches). Balls must have masses in the range 56.0–59.4 g (1.98–2.10 ounces). Yellow and white are the only colors approved by the ITF, and most balls produced are a fluorescent yellow known as "optic yellow", first introduced in 1972 following research demonstrating they were more visible on television.
Table tennis racket Table tennis regulations approved by the International Table Tennis Federation (ITTF) allow different surfaces on each side of the paddle for various amounts of spin (including nullifying it) or speed.[1] For example, a player may have a spin-heavy rubber on one side of his paddle, and no spin on the other side. The player can flip the racket in play for different types of returns. To help a player distinguish between different types of rubber used by his opponent, regulations specify that one side of a paddle must be red while the other must be black, allowing a player to see what side of a paddle hits the ball mid-play. The player has the right to inspect his opponent's racquet before a match to see the type and color. Current rules state that, unless damaged in play, the paddle cannot be exchanged for another at any time during a match.[2]