[old_tv_nut]

The flat plate bulbs in the Baird receiver and even the RCA 60 line receiver worked fast enough. The Early Television Museum has a working 60 line flying spot camera and receiver, which do give all the resolution possible at 60 lines, and is quite viewable (at least for one person at a time). A Western 45 line direct view set may have been just as good, but I have not seen one in operation. The pictures above are from the Museum's projection console. This used a neon crater lamp and a scanning disk with 45 lenses to project the scanning spots on a ground glass, instead of a flat plate tube and a disk with simple holes as used for direct drive. I don't know if the crater lamp was inherently harder to drive fast, or if the video amplifier was not as good as it could be, but it is certainly true that the brightness as demonstrated at the museum is impractically low.

I don't recall hearing about the use of mercury vapor bulbs, and I wonder if they were flat plate or point source (or line source for mirror-screw receivers).

Edit - I do recall different color bulbs being used for color TV experiments.