Why do we see "Colour Banding" on modern sets?

[Tempest]

I'm assuming it's the source signal, but then again perhaps it's our sets.
Does anyone know?

Firstly, you only seem to notice this on clear HD type of sources being fed to the screens (I assume low quality SD signal blurs it all together anyway?)

What I mean is, on my LCD (and on a load of Plasma's being fed from a HD feed in shops) (before anyone says it's only LCD's that do this)

You see a logo (for example) and coming away from the logo you have colour/colours fanning out from bright to black.
You can often see distinct bands where the gradual shades of the colours melt into each other.

I saw it (Very infrequently) on my Xbox360 (grey shaded sky for example) so just assumed it was the consoles colour palette limitations.
But I've also seen in on live HD sources (BBC HD trial channel) Mostly I guess the BBD HD Logo with the blended shades of colour fanning away from the central logo (also a computer source but I'd imaging the BBC has a good colour palette on their computer!)

And also in store (Curry's) on a wall of Plasma's (42" thru to 60") all being fed with a HD source, again, when you have computer generated Logo's, you can see bands of colour where they've done a gradual blend.

Thinking about this, it does only seem to show up when the image has been made from some computer generated thing (when they try do go very smooth and very slight blends over a large area of our screens.

So, I'm left still wondering if it's some limitation with computers that are being used to do the blend (does not seem lightly)
Or it's the display palette limitation on LCD's and Plasma's that is causing you to see this?

Anyone know what's going on?

=================== EDIT ====================
Not quite as bad as this, but this is what I'm talking about

http://i26.photobucket.com/albums/c145/Paul-rs/Colour_banding_example01.png

[Refrenz]

So, I'm left still wondering if it's some limitation with computers that are being used to do the blend (does not seem lightly)
Or it's the display palette limitation on LCD's and Plasma's that is causing you to see this?

While some LCD panels are 10-bit, most are still 8-bit which limits the amount of colours that can be displayed hence banding will be more noticeable on an 8-bit LCD panel. Banding could could also be introduced at source, i.e. due to compression techniques. There may be other reasons that could cause banding, if anyone else wants to add them (I don't know of any others) ...

[Tempest]

While some LCD panels are 10-bit, most are still 8-bit which limits the amount of colours that can be displayed hence banding will be more noticeable on an 8-bit LCD panel. Banding could could also be introduced at source, i.e. due to compression techniques. There may be other reasons that could cause banding, if anyone else wants to add them (I don't know of any others) ...

Thanks for the reply.

I did kinda wonder (at first) it it was my set, but going up to the SuperStores where they have brand new £2000 Plasma's and they still show it (to various degrees)

Don't get me wrong, it's not bad, guess it's just something we'll have to accept whilst the technology matures.

[Tempest]

Indeed, it does sound as you suggested 8bit vs 10bit.

http://answers.yahoo.com/question/index?qid=20071213172842AAThMWr

Even reading about a new Samsung TV on the AVForums (this particular model) it seems like it's pot luck if you got a 8bit or 10 bit panel on the same model (depending when it was made)

Hopefully 10-bit will become the norm sooner rather than later (as it seems they are out there on certain sets)

[jester]

I always thought this was down to the source material and the way its encoded via mpeg.?

[Refrenz]

Indeed, it does sound as you suggested 8bit vs 10bit.

http://answers.yahoo.com/question/index?qid=20071213172842AAThMWr

Even reading about a new Samsung TV on the AVForums (this particular model) it seems like it's pot luck if you got a 8bit or 10 bit panel on the same model (depending when it was made)

Hopefully 10-bit will become the norm sooner rather than later (as it seems they are out there on certain sets)

The 8 or 10 bit panel lottery with the Samsung (model M86/M87 if I'm correct) was a big factor in me not buying one. I used to have a 40" Samsung R88 which had an 8 bit panel and was umming and arring over the M86/M87 or Sony Bravia 32" D3000 (has a 10 bit panel) as replacements. I went with the Sony and I don't know if its due to Sony's Bravia engine, the 10 bit screen or just having a smaller 32" panel, but the picture on the Sony is better than the Samsung.

[Tempest]

I have to say, if what I'm hearing is true.
I'd quite like to upgrade my Toshiba 37" LCD to a larger 1080p set with 10-bit colour.

The worry I have is: My Toshiba gives such a superb image (esp when gaming) I don't suffer from ANY of the bad issues I hear so many talk about with other sets.

Plus I have a perfect panel with no pixel faults at all.

I'd be gutted to buy new and have an iffy pixel or two (I had to send the 1st Toshiba back due to 1 dead sub pixel)

Anyway, my best (easy to see) example now is the background screen on my new Playstation 3
The background with the swirly wave, all made up of subtle blends of colours moving about.

When you look close, you can see banding moving about due (poss) to the screens 8-bit colour range.

(I assume it's not the PS3's pallet causing this?)

I'm also aware a Plasma may blur/blend this together and hide it a bit more than a LCD which just shows it as it is (warts and all)

I'd be interested to hear from other PS3 and LCD Owners of what they're screen looks like up close with the wavy background wallpaper, and slight banding between the shades of colour.

[Tempest]

As I said, I've still seen some banding on 42" and 50" Plasma's in store being fed from a HD Demo source.

The banding was not MASSIVE, but it was still there if you looked for it.

Foolishly I'd assumed it was the 8 bit vs 10 bit thing. But (with Plasma) now I read this:

Conventional Plasma HDTVs use 10-bit color processing that produces up to 1.07 billion colors. But Samsung has taken HDTV Plasma to the next level with sets that have 18-bit color processing. These technologically advanced color processing methods can produce astonishing natural, true-to-life colors. It also aids in the video signal processing of analog sources to ensure a more natural and vivid picture.

:brickwall