Uniformity compensation software?

Poor backlighting on LCD monitors (the kind that makes what should be a solid color appear to be a gradient) drives me nuts. It's that gradual fade from darker to lighter, top to bottom, on most monitors.

Using Photoshop I was able to use a light gray-to-white gradient (on a Multiply later) to overlay a screenshot of my desktop. After tweaking the transparency settings a bit, I was able to compensate for the LCD's poor backlighting and make the colors more consistent. But this was only a screenshot and not my actual desktop.

Is there some software that would let you tweak the video card's output image so that the bottom half is slightly darker than the top half (and fades to it, gradient style) to cancel out most LCD monitors' tendency to become brighter near the bottom of the screen? Or even, software that lets you overlay your whole desktop with a transparent image?

It's not the backlight. Darker on top, lighter towards the bottom is the characteristics of a TN based panel. Other than that, each panel can have variances in backlight bleed, which is again just variance in the crystals themselves, not the backlight.

If your issue is the former, a different panel type can solve the issue. VA based panels do not suffer the verticle variance, but have horizontal varience as well as some other issues. While IPS based panels only suffer from the "glow" which all LCDs suffer from (some worse than others) and somewhat higher black point, causing them to have lower actual contrast ratio (not ususally an issue). Some also suffer from image retention.

It's the same problems LCDs have had since their inception and no software has worked to fix the problem. I believe Samsung was the only ones to try it, and it pretty much failed.

vick1000 said:

Darker on top, lighter towards the bottom is the characteristics of a TN based panel.

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Is this true of every TN panel?

How much of this is normal? Here is roughly the difference between the bars on the forum when at the top and bottom of my screen:



Is this more than normal? If I exchange my monitor for a new one of the same model, would I be likely to get a better one?

Demigod Mac said:

Poor backlighting on LCD monitors (the kind that makes what should be a solid color appear to be a gradient) drives me nuts. It's that gradual fade from darker to lighter, top to bottom, on most monitors.

Click to expand...

This problem can occur in any panel (TN, VA, IPS, etc.).

See this brightness uniformity measurement in an IPS panel monitor review (posted in March, 2013).


(Source: Review of Eizo EV2736 by prof howard (howardkim) at http://colormgmt.com/60187285671)

Holy thread necro batman!

Tup3x said:

Holy thread necro batman!

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That's some potent necromancy...

Matter said:

If I exchange my monitor for a new one of the same model, would I be likely to get a better one?

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Can no longer see the picture so it's a long answer:

If you are referring to a uniform gradient top to bottom it can be the "normal" effect of the TN when looking at it from different angles.
You can try to look at it from the other side of the room, if the gradient disappears or gets weaker it's the TN-effect. (you'll be looking from roughly the same angle at the monitor top and bottom)

Getting a new monitor of the same type will not change that it's a TN with bad viewing angles.
You'd have to get better TN or ideally PVA/MVA or IPS/PLS monitor to change this. Other panels have different effects (crushed blacks in a PVA center, white-glow on a IPS without ATW Polarizer) but not a strong top-bottom gradient.

If the gradation you are referring to looks the same independent of the viewing distance and angle it's likely an issue of having an inhomogeneous backlight. These are mostly cloudy patterns, often in the corners, but a top/bottom gradation isn't impossible.
This effect can vary from monitor to monitor even if it's the same model.

To my knowledge there's no compensation software available for either effect.
(apart from some monitor internal compensation of backlight non-uniformity on some high-end models)