Move to yellow ball begins
On the recommendation of Eagle Rubber Company, the APTA introduced a yellow ball (the “night ball”) in 1972.
Other ball manufacturers soon followed their lead. Vittert produced the V-29 ball while Marcraft introduced both a red and yellow ball named “Big M.” Other manufacturers, like Barr, Puma and Bullet began producing orange and red balls as the game took off through the 1970’s.
Source: Christina Kelly,Passing Shots: A Pictorial History of Platform Tennis, 2010 and Robert A. Brown,personal communication.