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September 13th, 2006 22:00
2007WFP - strange dithering effect
Hello,
I've received my DELL 2007WFP and I'm very pleased with the overal built quality of the the monitor, the colors are really stunning. :-)
However, I have noticed a strange dithering-effect. I'm not sure if this is just normal and I have to accept it since this is my first real TFT. I have not noticed this effect on any other TFT I've seen and could not find any information on the internet.
The effect: If I move my head back and forth, I notice a strange dithering effect on mid-tone colors.
The pattern is well ordered, chess-like and one pixel wide. It can also be seen if you "glide" your eyes over the screen, for example while watching a movie or moving a window. It seems to be the panel's pixel control somehow.
I can't see it if the distance is > 1m or if you don't move your eye. It is visible on any resultion and it's connected with the TFT's own resolution. It's pretty faint, but confusing me :-)
The monitor is connected via analog VGA to an Apple iBook G4, I haven't tested DVI so far, but I'll do soon. I don't expect any improvement since the pattern can be seen on the blue screen menu even if there is no signal connected to the monitor.
Besides that I'm really surprised how great the analog VGA quality is. It's a Rev. 02, made in CZ with a Philips LM201W01 panel.
Can anyone reproduce this phenomenon?
(I'm sure that this is not the crystal-effect of the S-IPS panels which can't be really seen on my screen.)
Best regards,
Sebastian
I've received my DELL 2007WFP and I'm very pleased with the overal built quality of the the monitor, the colors are really stunning. :-)
However, I have noticed a strange dithering-effect. I'm not sure if this is just normal and I have to accept it since this is my first real TFT. I have not noticed this effect on any other TFT I've seen and could not find any information on the internet.
The effect: If I move my head back and forth, I notice a strange dithering effect on mid-tone colors.
The pattern is well ordered, chess-like and one pixel wide. It can also be seen if you "glide" your eyes over the screen, for example while watching a movie or moving a window. It seems to be the panel's pixel control somehow.
I can't see it if the distance is > 1m or if you don't move your eye. It is visible on any resultion and it's connected with the TFT's own resolution. It's pretty faint, but confusing me :-)
The monitor is connected via analog VGA to an Apple iBook G4, I haven't tested DVI so far, but I'll do soon. I don't expect any improvement since the pattern can be seen on the blue screen menu even if there is no signal connected to the monitor.
Besides that I'm really surprised how great the analog VGA quality is. It's a Rev. 02, made in CZ with a Philips LM201W01 panel.
Can anyone reproduce this phenomenon?
(I'm sure that this is not the crystal-effect of the S-IPS panels which can't be really seen on my screen.)
Best regards,
Sebastian
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CyberSeb
2 Posts
0
September 15th, 2006 15:00
it's me again.
I was able to create some photos of this effect.
You can see them here:
Image 1
Image 2
Image 3
In 1 everything is just fine. All pixels light up a nice green color. In 2 and 3 you can see what is often called a "checkerboard" pattern. Note that the pattern is 2*1 pixels (x*y).
I've done some research on this effect and I think I know the cause.
It is caused by the panel, how it drives the pixels. This is called "Inversion" and is well explained here:
http://techmind.org/lcd/index.html#inversion
I have created a "flickertest"-image which has 2 pattern areas. The do match the photos I took from above, the ones on the techmind-side do not. If you display it on your 2007, only one area will flicker, the other not. It changes side if you move the picture by one pixel to the right or left. This ist just fine according to the page above.
Flickertest Image
The effect has also affected other Dell-displays as you can see in these threads:
http://forums.us.dell.com/supportforums/board/message?board.id=dim_monitor&message.id=51419&query.id=61225#M51419
http://forums.us.dell.com/supportforums/board/message?board.id=dim_monitor&message.id=41130&query.id=61278#M41130
http://forums.us.dell.com/supportforums/board/message?board.id=dim_monitor&message.id=40559&view=by_date_ascending&page=1
Can anyone reproduce this effect? I would really appreciate any form of comment. Maybe I'm just to picky or mad. Is it just the TFT-technology?
I know other TFTs don't have, but they all use different panels.
My Mom and sister were not able to reproduce the effect, my Mom said she would be quite happy to have such an amazing monitor at work. :-) I will visit an friend, I think he can see it.
Best regards
Sebastian
Message Edited by CyberSeb on 09-15-2006 11:39 AM
Message Edited by CyberSeb on 09-15-2006 11:40 AM