phosphors in roundies

[timmy]

hey all is it possible to have 3 roundie sets with 3 different crts in them and have the colors alittle different from one to another? i know old sets cannot be compared with a newer crt tv as the colors differ. but i have the silvertone crt an fb, the magnavox crt which is newer 19h something and an rca fj would the phosphors be different between these 3 crts? just curious.

[consoleguy67]

I have a 1967 Zenith roundie console, and a 1964 Magnavox roundie combo, and their pictures are very different.

[old_tv_nut]

Phosphors in the FBs and FJs changed over the years, even though the electrical specs were the same.
The blue is zinc sulfide in all of these. The green is either zinc sulfide (yellower than P1) or zinc cadmium sulfide (even yellower) in all of these.The red changed the most. The tubes with the greenish face are all-sulfide tubes, with zinc cadmium sulfide red. Later, the red changed to vanadate in some tubes, then to europium oxy-sulfide in rare earth roundies and subsequent rare-earth rectangular tubes.

[edit] - as I have noted before, the color rendition of a chassis is also highly dependent on the demodulator gains and angles, so comparing the colors in the picture as an indication of CRT differences is risky. The exact same tube in different chassis will look different.