Questions on brightness of old colour TVs

[bgadow]

My understanding is they could,early on, get a bright green & blue but getting a bright red was a challenge. They had to scale back the green/blue to match. Then in the early 60s they came out with rare earth phosphors which allowed brighter reds, so all 3 colors could be boosted. I think the tube in the CT-100 was especially bad due to its unique construction, with extra layers of glass between the electron beam & the viewer. Gradual improvements, in both the crt's & the electronics, came along the way.