Our station had an art department that used a hot press to create text boards that were set on an easel that had a camera pointed at it. By using a black background with white text you could merge the text camera with a camera in the studio and "super-imposed the text into the video feed.
"And if you tell the kids that today, they won't believe it!"
It's kind of amazing the sort of hoops people needed to jump through to make e.g. the BBC-1 ident: https://www.youtube.com/watch?v=xfpEZDeVo00