Perfect adjustment of your LCD

eirikso
Pixels on an LCD

When connecting my QPVision 37″ LCD to my media center through DVI I had no problems running the native resolution of 1366×768 on the screen. This gave me one-to-one pixel mapping and a completely sharp picture.

However, my friend Staale ran into some problems that seem to be quite common. He did some tests and created a simple and very effective test pattern that can help you find the right resolution.

It seems like quite a bit of LCD screens that has a resolution of 1366×768 report to the screen cards that the correct resolution is 1360×768. Seems like a small difference, but when you run 1360×768 on a screen that actually is 1366×768 the screen sometimes does a bit of scaling that makes parts of the picture slightly unfocused.

Here is an example. The first picture is taken as a super close up of the screen in 1360×768. The next one is the same area on the same screen forced to 1366×768 through the advanced settings in the screen card driver:

Screenshot of resolution 1360x768 Screenshot of resolution 1366x768

And here is a detail of those images:

Detail of 1360x768 Detail of 1366x768

The difference seems big here, but it can be difficult to detect and that is where Staale’s brilliant test pattern comes in. It is a simple grid of black and white pixels that will clearly reveal a screen that is not mapped one-to-one. You can download the image here:

GIF (3 k)
PNG (4 k)
BMP (1,2 MB)

It should never be converted to a JPG. Any lossy compression will destroy the file.

Download it and insert it as your desktop pattern. Centered and not streched.

If your screen looks like this:

Screenshot of a perfect resolution

…then you have a perfect one-to-one pixel mapping.

If it looks like this:

Screenshot of problem with the pixel mapping

…then you have a problem with your pixel mapping.

Unfortunately it can be difficult to solve the problem. It depends on the screen, your screen card, the firmware in the screen, your screen card drivers, the software you use etc… It involves advanced tools and might even put you into serious trouble with your screen and the image from your computer.

For relatively new Nvidia screen cards and drivers you have options to take complete control of the refresh rates and resolution to the screen. You can also try playing around with PowerStrip. Or, use AVS Forum. An excellent source of information on advanced use of media equipment.

Digg this story here.

And please feel free to comment if you have solutions to this problem for specific setups.

Perfect adjustment of your LCD

20 thoughts on “Perfect adjustment of your LCD”

  1. Emil N says:

    Nice one, I will certainly remember this!

    But, why on earth use BMP? – Ever heard of PNG or GIF?

    Using PNG, I was able to downsize the picture to 4 KB, instead of the 1216 KB BMP one. 😀

    You’d spare some traffic on this one.

    Reply

  2. I guess the BMP was an extreme result of lazyness. The original was BMP and I didn’t bother to convert it… 🙂

    Thank you for your feedback. I have now published a PNG, a GIF and edited the post.

    Reply
  10. unruled says:

    Ive never succeeded in getting the pixel mapping correct on my thompson 32″ 720P tv.
    I can run it in 1280×720, and 1360×768, but both have incorrect mappings.
    I decided to try the 1366×768 you have mentioned here, but nvidia rejects the resolution when I try to add it, stating that it’s invalid.

    Any ideas? 😦

    Reply
  12. unruled says:

    thanks for the reply 🙂
    the tv im using is http://www.hdtvsolutions.com/Thomson-32LB040S5.htm, connected to my PC with a VGA cable.

    With powerstrip I got 1366×768 added, but it still doesn’t look right.
    (see http://img220.imageshack.us/img220/9227/dscn2027mg7.png ). Its not the end of the world, but it’s irritating :/

    My guess is that either Im just a few pixels off, or.. my tv just isn’t very good at accepting PC signals (or VGA cable stinks). I guess I will have to just put up with it.

    Thanks a lot for the help though!

    Reply
  13. Piter_neo says:

    I have very important question.

    Can I achieve 1:1 pixel mapping by hdmi on e.g. PS3 or X360? I mean, can I have perfect 1280×720 on lcd with 1366×768 resolution, so I’ll get picture with black frame, black stripes on sides and top/bottom?

    Reply

  15. Confused!?

    So you mean that it is possible to get 1:1 pixel on any lcd-tv as long your video card can send the correct resolution?

    I have bought 2 two tvs and returned them because I couldn’t get full pixel display, one is HDReady 42PFL3312 and the other one is FullHD LE-40M87BD. I even tried with PowerStrip with all different settings like 1366×768 on the HDReady and 1920×1080 on the FullHD.

    Should I have tried some more settings or are some tvs impossible to get right?

    Reply

  16. It’s difficult to know if it’s the TV or the video card that is the problem. On my TV I got the correct resolution at once. On some TV’s it’s impossible, and on some it’s difficult, but not impossible. http://avsforum.com is a good resource for these issues.

    Reply
  17. Todd says:

    I own a Sony VPL-VW11HT unit. One of the LCD panels has gone horizontally ugly on me. It scolls like crazy. I have a gentleman in Hong Kong can that can send me a new LCD, but he says it takes special tools to install the panel. I have no idea what he is talking about, and thought that maybe your topic of convergence and pixel setup, might be the ticket. Please help!

    Reply

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