noob LCD questions

[woooooter]

I just got a brand new samsung 245bw and coming from a 21" CRT, I am a bit disappointed.

http://img217.imageshack.us/img217/8400/helpce9.jpg

my first question is why that happens. it gets really frustrating trying to watch a dark scene in a movie. how do I adjust it so it stops happening?

I also get matrix style vertical green lines on the display with all resolutions below 1280x1024, but no lines at all on my CRT which I ran at 1024x768 with, so I don't think that it is my 8800 gts.

can anyone shed some insight and explain how to fix this mess or is my monitor a dud?

 

[woooooter]

nevermind the green line issue, I reversed the dvi cable and it seems to work fine now at all resolutions. hopefully it doesnt come back 🙁

but I still want to know why it does that multiple shadow effect on movies though.

 

[jaguarskx]

You are experiencing what's called color banding. Color banding occurs when the transition of one color/shade to another is not resulting in a smooth blending effect.

Although all types of LCD panel technologies can suffer from color banding, TN panels are most susceptible to it because of the limitations of the technology itself. The Samsung 245bw uses an LCD panel based on TN technology.

TN panels uses 6-bit color (a.k.a. 18-bit color) tech as opposed to other panels (MVA, PVA, IPS) which uses 8-bit (a.k.a. 24-bit color) tech. What does that mean?

6-bit

6 bits of data are used to represent each color: Red, Green, Blue. Thus there are 64 shades of each color: 2^6 = 2 x 2 x 2 x 2 x 2 x 2 = 64

Since there are 3 colors that means 262,144 actual colors can be reproduced: 64^3 = 64 x 64 x 64

This type of panel tech uses a process call dithering to blend up to 16.2 million colors. Dithering is a "guesstimate" and can result in color banding and other types of image artifacts.


8-bit

MVA, PVA, and IPS panels all use 8-bit colors and a slightly different manufacturing process which makes these types of panels more expensive to produce, especially IPS panels.

Again, there are 3 color (Red, Green, Blue), but with 8 bits to represent each color, there are up to 256 shades of each color: 2^8 = 256.

256 shades of each color means 16.7 million colors can be reproduced: 256^3 = 16.7 million.

Since there is no guessing involved there are fewer artifacts than TN panels.

24" MVA / PVA generally start at about $575 online (at least the good ones).

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Other technologies can also play a role in color banding issues. As an example: The 26" Planar PX2611 (~$900) and the NEC LCD2690WUXi (~$1,200) uses the same H-IPS panel produced by LG-Philips. The Planar exhibits color banding issues when connected to a console (Xbox 360, PS3) when set to 1080p resolution. The NEC does not experience this issue probably because of the extra video processing electronics or perhaps slightly higher quality input ports, but it could also be other things as well.