CurtPalme.com Home Theater Forum

[ElTopo]

May this be possible with the correct color filters ?

cheers
ElTopo

[cmjohnson]

No, not in any practical sense. BT2020 pushes red, green, and blue farther out than anything before.

The CRT phosphors just don't put out much light at the target RGB values for BT2020.

All color filters do is eliminate the wrong colors, they can't create the right ones.

[cmjohnson]

Here is one CRT colorspace chart that outlines the differences between NTSC, HDTV, and the UHD BT 2020 specification.



Our CRTs are built with phosphors selected for good performance offering a compromise between color accuracy and light output. They were chosen when NTSC was all we had, long before the advent of HDTV and even before the computer had any presence in the home.
Not all phosphors are capable of the high light output needed for a projection CRT. That's why we use red and green C elements for greatest color accuracy. But by doing so, we're throwing away some light output and driving the tubes harder, resulting in reduced tube life.

Filtering for BT 2020 would seem to be unlikely to be successful.

None of our CRT native colors are very close to the BT 2020 specs. Red isn't deep red enough, blue would have to move toward indigo, and green would have to be deeper green as well.

[CIR Engineering]