I've got a Samsung SyncMaster 204B monitor. One of the features it has is that it lets the user physically rotate the display 90 degrees so that the monitor is in portrait mode, which would be useful for looking at long documents. However, when I do this, there is a significant drop in display quality. Is there some setting I need to change? Or is this just how LCDs work?

  • 2
    Whaddya mean "significant drop in quality"
    – bobobobo
    Aug 7 '09 at 21:17

There are two issues.

First, the arrangement of subpixels - Microsoft's ClearType is optimized for horizontal arrangement of subpixels. I'm not aware of any LCD panels that are made with vertical subpixels. You might be able to configure ClearType to lessen this problem.

Second is the viewing angle of the display. There are different LCD technologies, and the cheapest don't have very good vertical viewing angles. When you rotate the display, those vertical viewing angles become horizontal viewing angles.

  • 2
    Yeah so.. turn off cleartype. That's great advice if I ever heard it. Even if your monitor is in its normal orientation (I hate cleartype!)
    – bobobobo
    Aug 7 '09 at 23:27
  • 7
    Oh sweet jesus, never turn off ClearType unless you want your eyes to bleed! Vista and 7 automatically take monitor orientation into account when doing cleartype rasterizing; it's even handled on a _per-monitor basis+ so you can have one rotated, one not. Sub-pixel rendering definitely works best with a standard RGB or BGR, but readability is still improved when it's RGB vertical or BGR vertical. Aug 8 '09 at 3:25
  • 1
    ClearType does not support vertically stacked subpixels. Calibration does not help.
    – usr
    Dec 29 '11 at 21:48
  • Actually if u not happy with fonts in Portrait mode Disable - To "Smooth Edges of screen fonts". sevenforums.com/tutorials/… Aug 30 '14 at 9:23

Yes and no. Most consumer LCDs are based on the TN lcd panel technology (cause it's cheap) which doesn't have very good viewing angles. You can generally determine if you have a TN display by looking off center (up or down) at your lcd and if it appears that changing the viewing angle the brightness/contrast/color changes as well, then chances are, you have a TN. Now, when you rotate a TN, those vertical angles become horizontal angles and since your eyes look at the screen at slightly different horizontal angles, the monitor would look pretty bad. (I had a TN monitor mounted on a pivot arm and i basically had to look at the monitor at an angle to be able to read something in a portrait mode .. looking at the monitor straight on would give me a headache after a while since my right eye would see the monitor darker than my left eye. Looking at the monitor off center with the top of the monitor closer to you gives better viewing experience)

However, if you have an MVA panel lcd (or even better, an IPS based one), portrait mode would look so much better so in this case, the question to your answer would be no. Basically ... it's the old saying - you get what you paid for. If you are going to buy monitors that you want to use in portrait mode, make sure you buy one with excellent vertical viewing angles (i.e. get an IPS or MVA based lcd panel).

This site has brief description of the common lcd panel types if you are interested in reading more about it.


There are three types of LCD panel: TN, VA, IPS

These are in order of increasing cost and (generally) increased quality of image, so TN is the worst quality but cheapest, and IPS is the best quality and most expensive.

TN monitors have pretty terrible viewing angles, and so rotating one 90 degrees will give the change in quality you mention -- viewing them from anything but fairly straight-on will mean that colours start to go very strange and possibly inverted, and brightness can vary a lot across them.

So, to answer the original question:
No, not all LCD monitors do this. Just the cheap ones!

edit: TN panels generally have poorer viewing angles in the specs, so they are likely to say something like "170 degrees vertical/160 degrees horizontal" rather than the 178/178 which VA and IPS panels will state.


It might be due to the TN panel in the monitor which leads to bad angles, so when you tilt it you get it horizontally instead of vertically which might be more unusual for your eyes then the bleeding and color-distortion you get when looking at it the normal way. It's the same for me when doing it at my university's monitors and probably something you can't get away with when dealing with TN panels.

  • 1
    It's not enough to just say "TN" - this technology has many variations, and some will be worse than others. Aug 7 '09 at 21:33
  • You are correct Mark, maybe the answer should have been more geared at the "community information gathering process" then at the specific question. Most TN panels I have ever been in contact with has the same set of problems, hence the answer. Your answer was above and it was mostly a continuation of that. Aug 7 '09 at 21:39
  • I probably wasn't clear with my first comment. Different versions of TN can have different characteristics. It's possible for a manufacturer to substitute one panel for another in the same model LCD, so you can't even be sure of what you're getting. Non-TN panels are also available but are usually not seen due to their expense. Aug 7 '09 at 21:52

What I just found to make the big difference (and solution!) was swapping the input (DVI / VGA):

  • normal (landscape) at VGA/analog
  • rotated (90degrees) at DVI/digital

It took me some time, some investigation (like reading this web site) and even changing a few monitors, to finally discover this big difference. I thought it might be helpful to share this for many others to save time, as almost all PCs and monitors today are by default setup with both ports.

So: normal situation with multiple monitors, there was no (apparently) difference/problem. Rotated a screen: poor quality (like resolution was too low). ClearType did not have to do with it. Solution: connecting the rotated screen on DVI (white connector).

Monitors used: HP L2245wg (1680x1050) and LG 2350V (1920x1080). Videocard NVidia GeForce 8400 GS. Running Windows 8.1

  • I can say almost opposite I have 3 monitors rotated 90 degree and Best quality was on VGA connected to PC through DisplayPort while DVI-D ones had dark area at certain AngleView. Aug 30 '14 at 9:32

This might be due to the arrangement of the subpixels. Using subpixel smoothing does not work in portrait orientation, and will look wrong, or depending on how smart your operating system is, will be disabled.

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