[old_tv_nut]

The fact that you have seen the same sort of swirl on two different tube types that used different methods of application is really interesting. I have never seen anything like this.

In the 70's, Sylvania came up with a brighter phosphor slurry that was thicker than usual. Motorola had trouble using the thicker slurry because of broad swirl marks, but they were faint and only showed up when the tube was lit. Engineering staff were commandeered to take two identical 19 inch sets (except for old and new slurry) home and get unprompted comments from their families to find out if anyone could see the swirls as well as the difference in brightness.