[old_tv_nut]

Zenith's gated beam tubes and IC color demods were both ultralinear compared to the pentodes or other tubes used by other makers. Differences in greens and other colors between gated-beam and IC Zeniths was likely due to differences in phosphors over the years combined with changes to the demod gains and angles to compensate. The all-sulfide CRTs in particular used a zinc sulfide green with cadmium added to make it yellower and brighter, resulting in visibly desaturated true greens and cyans. Also, because the white point was already moved towards cyan to take some load off the red gun, cyans looked grayish by comparison. This was reduced to a degree when rare earth red was introduced and cadmium was removed from all formulations for environmental reasons. This gave pretty much a standard phosphor set for years to come, but manufacturers differed in the white point they set and the compensating adjustments in the color demods.

In the end, basically the same phosphor set was selected as the standard for PAL, HDTV and still photos (sRGB), but the compensation was moved to the camera or computer instead of the receiver/monitor.