It seems that, prior to the Jetsons Color broadcast in the 1960s, the ABC Network feed was 30.00fps B&W. Prior to the Jetsons, it must have been a challenge for affiliates of ABC that had local Color ability (or were affiliated with NBC or CBS also) to have to change between 30.00 and 29.97. With the technology available then, it wasn't possible for a local affiliate to convert 30.00 to 29.97. I don't recall reading anything about this type of problem during the transition to Color though. Kirk Bayne