Trouble calibrating LED Monitor - AVS Forum
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post #1 of 2 Old 05-17-2012, 06:16 AM - Thread Starter
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Hello,

I am relatively uneducated in the art of calibration. I know enough to get excellent pictures on my TVs compared to stock settings, but my new LED computer monitor is driving me mad. It's an ASUS VE248H connected to a Radeon HD 7850 by an HDMI cable. Out of the box, the settings give a yellow hue to white backgrounds. Also, greens are much too bright. A lime green color will cross your eyes.

I'm not alone on this -- many reviewers say it's a good monitor but the stock settings are crap. The weird thing is I can't get the adjustments right which has never happened to me before. Using these test patterns (http://www.lagom.nl/lcd-test/) I end up drastically adjusting the individual color contrasts and gammas. The whites end up much whiter, but everything else looks unnatural. I would describe it as oversaturated and "too blue." But lowering the color saturation setting doesn't seem to help and if I reduce the intensity of blue, I end up right back where I was with yellow tinted whites.

I've tried this 4 or 5 times and I'm at my wits end. From an expert, how would you go about this process. Let's assume for the sake of practicality that I don't want to invest in a colorimeter that probably costs more than my monitor itself. (I know that's the right way, I just can't afford it.)

Thanks in advance
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post #2 of 2 Old 05-18-2012, 09:38 AM
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You can't really know where your settings are without a meter. And you can't fix a video display if the controls it has don't do the right things. I you are relying on the controls in the video display driver in the computer... they may not be able to do what is necessary to get a video display that's problematic to do the right things.

There are 2 issues with video display controls... one is whether you can use the controls to get grayscale and color accurate or not. With grayscale, you typically have at least 2 controls (high luminance and lower luminance) to help try to get the grayscale reasonably accurate. For colors... red, green, blue, cyan, magenta, yellow... there may be no controls, only one or 2 controls per color or the proper 2 controls per color (hue, saturation, and brightness for each of those 6 colors). But you can't use those controls without a meter and get any kind of results that will make sense (and your meter would have to be accurate while measuring light from LED backlights, many lower cost meters are only (sort of) accurate for CCFL, plasma, and CRT displays). Then there's the issue of linearity... for grayscale, linearity can be really good or really bad... it just depends on the display and the controls that are available. If there are 10- or 20-point grayscale controls, you can tpyically get really good linearity, meaning that the grayscale stays nice and neutral no matter how dark or light the shades of gray may get. With just 2 or 1 or no controls, the linearity can get pretty bad if the display is not well-engineered. For color, we typically adjust with 75% colors (roughly 50% stimulus for 2.2-2.3 gamma) because this is in the middle of the luminance range. If you use 100% colors, you'll all the way at one end of the luminance range and things can drift a lot more. But you can't adjust these controls without a meter either. And in a poorly engineered display, that one set of adjustments (if they even exist) might get the display accurate at the point you choose (say 75%), but the display could drift A LOT at higher or lower luminance levels. Nothing a calibrator can do with that.

You may not be able to fix the display problems without more/better controls. If those controls are in the video display subsystem in your computer and it can be upgraded, you may find that a better or more flexible video subsystem comes with more comprehensive controls. But you'll need a meter to make use of them, you can't really do much by eye.

If the controls you are relying on are in the display itself... you may have to get a better display. Or you may have to look at the controls in the computer to fix problems that the controls in the display can't fix. But there's no guarantee the computer's controls will help. And you still need a meter to know what's going on.

And the meter isn't really any good to you without calibration software and a knowledge of the calibration process you'd have to teach yourself over 100 hours or so of study and practice.

There are no shortcuts to this process. And there's no such thing as test patterns that work without a meter for the sorts of problems you are having.

"Movies is magic..." Van Dyke Parks
THX Certified Professional Video Calibration
ISF -- HAA -- www.dBtheatrical.com
Widescreen Review -- Home Theater & Sound
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