Hi
Further good reading. Again in TELEVISION magazine, a series of articles by Eugene Trundle entitled "The Development of Colour Tubes" was in the June to October 1986 issues. These are also available from American Radio History website, eg the first part
https://www.americanradiohistory.com...UK-1986-06.pdf
The October issue had an article on beam indexed tubes but for some reason appears to be missing in the ARH copy. I should have this issue to hand so can provide a scan of the article if anyone wants a copy.
Regards,
Symon