There are those ads for the new Sharp Quattron TV sets that have on extra layer for Yellow which is supposed to give better color. Will that make any difference if the source doesn’t have any info for that channel?
I don’t know how TV signals are sent, but I am guessing color is RGB all the way from the camera that shot it to the TV signal you get on your antennae or cable. What will that Yellow layer do with no info to display?
It will depend on how the signal is encoded. The “sent” colors don’t have to match the colors of the pixels. The representable colors in a three-color system are always inside the triangle of the three colors, but those three colors themselves don’t have to be realizable. Only the colors inside the triangle of the pixels are realizable. Colors outside will just be shown as a nearby color. If the encoded colors cover a larger portion of the visible range than the three pixel colors do, then a fourth pixel color can make the realizable range larger.
There’s a standard three-color map that covers the entire range of human-visible colors. See the picture here. If what is sent are based on C[sub]r[/sub], C[sub]g[/sub], and C[sub]b[/sub], then all colors could be represented. But I don’t know what encoding TV uses.
I’ve already addressed that in this earlier thread:
What are the CIE coordinates for the colors broadcast? Is the broadcast triangle significantly larger than the gamut an RGB display can handle?
You wouldn’t think adding yellow would add much if you just looked at it:
But the diagram is deceiving – the eye is a lot more sensitive in green and yellow than in blue, so that little sliver near yellow may make an appreciable difference.
Oh, I searched for Quattron and found nothing.
I agree with your observation there that it seems like we are missing a lot more on the green-blue side than we are on the yellow side. I see you also mention that it might mean squat without a signal that provides something for that layer to display.
I guess we will have to wait and see until it is out there and we can check it out at a store.
I guess I don’t see what this gamut represents. If it represents the gamut that is broadcast then I clearly see why a yellow would add to the display. The border is practically on the spectral line for yellow. I don’t know how close standard RGB displays get to the yellow.
I’m not sure what the gamut is – but most TVs and Monitors represent yellow pretty well (If they didn’t, you wouldn’t be able to see the yellow fish in that ad). Their claim is clearly that you get more yellow – because they include a yellow phosphor that isn’t in the standard set, so you get some extra color space represented.
You can’t really go by the picture I linked to, because I don’t know how well it represents real sets, and because how close the edge of the triangular gamut is to the spectral locus (the curvy line bounding the Chromaticity space) doesn’t really tell you how big a difference you’ll see. Regions of indistinguishable color – what Dave MacAdam called “color ellipses” – vary in size and orientatioin across the CIE diagram, and so equal sizes on that chart don’t represent equally distinguishable regions of color.
It’s also possible that the green pixel has been changed to be around 520, with yellow added near 570. That’s too complicated for easy marketing, so they just say “we added yellow”, even it’s really mostly giving you a better aqua.
IANA tv expert, but I remember hearing that certain professions still use CRTs because they are superior in some ways with regards to color portrayal. So I would guess that the Quattron, being flat, uses the inferior LED or LCD or whatever, and the extra yellow makes up for whatever usually causes LCD/LED not to look as nice as CRTs. Since broadcast color info was originally intended for CRTs, there’s no problem with missing info at the source. *This has all been a WAG.