So. A while back while clearing Lucian's stuff. We took possession of some valves. In there was a Vidicon tube. I sadly had to return that as it went to the broadcast museum peeps.

Cut to yesterday when we got another batch of choobs from a friend..... Containing not one.
Not two.
But THREE Vidicon choobs o.o

This is how stuff was filmed on analogue TV o.o

It's effectively a back to front CRT.

The front is a special coating that can "store" an image that's being projected on it.
Then a scanning electron beam within the tube flashes across the front plate in the same manner as in a CRT. The electrons interact with the light and dark parts of the image and are spat out via a ring at the front.

One tube for black and white. Often 3 of them for colour.