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How We Tested

CCFL Versus LED: Is There A Downside To Going Green?
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Most of you probably know that monitors benefit from calibration, and what you get out of the retail box is not calibrated. Instead, displays generally arrive cranked with maximum settings so they look bright, vibrant, and ready to rip your face off with radiant awesomeness. This may make for a great first impression, especially at a distance, but these are almost always sub-optimal settings. The red, green, and blue color channels may benefit from tweaking, the target output brightness is almost always less than what you see at first. And the general “temperature” of the display (used in the color, rather than heat meaning of the word) may need adjusting. The one spec that vendors tend to nail at the factory is gamma. The optimal gamma setting is 2.2, and this is almost invariably what you get.

We know that some if not most users resist calibrating their screens for whatever reason. A proper calibration requires a proper colorimeter, which in our case looks a lot like a corded mouse that you place over the display screen. A sensor inside the puck takes readings from the monitor, and software running on the PC converts these readings into various values. We started testing with a Monaco Optix XR colorimeter, graciously sent to us by Asus, with ColorEyes Display Pro. However, this is a somewhat older colorimeter, and there’s some debate about whether it’s still suitable for testing given more current options. We suspect it is, but we opted to compromise and go with X-Rite’s i1Display 2 bundle, which includes both the i1Display 2 colorimeter along with X-Rite’s i1Match software. After speaking at length with X-Rite engineers, we were convinced that this package, plus ColorEyes Display Pro and Chromix's ColorThink Pro, would be sufficient for making a reliable quality analysis suitable for a consumer-level audience. In a perfect world, we would have five figures to drop on Minolta colorimeters and luminance meters, but then you wouldn’t have had scantily clad elves in our holiday hardware roundup until 2017. Faced with that dilemma, we opted to accept X-Rite’s generous help.

Right out of the box, we noted the factory brightness, contrast, and color settings for each display. We then ran X-Rite’s Eye-One Match Easy test to determine color temperature, gamma, and luminance at these stock settings. Next, we used the Eye-One Match Advanced test to calibrate the screen and create a calibrated profile. After discussions with X-Rite and Chromix, we agreed on targets of 6500K for temperature and 120 cd/m2 for luminance. We see 120 cd/m2 noted repeatedly throughout the professional display world as being optimal for desktop monitor use, although your first look at it may seem surprisingly dim because you’re accustomed to an overdriven screen brightness.

With the screen calibrated, we then returned to Eye-One Match Easy and used it to take readings at nine positions around the display: top-left, top-center, top-right, middle-left, middle-center, middle-right, bottom-left, bottom-center, and bottom-right. Taken together, these readings would reveal any significant variances in luminance and color across the display surface.

Next, we used ColorThink Pro to measure gamut, comparing the measured output from the calibrated screen against the sRGB baseline gamut. Essentially, this shows the amount of perceptible color the monitor is displaying compared to the industry-standard sRGB profile. There are many alternatives to sRGB, but we opted to use it for its ubiquity and simplicity.

Finally, we used ColorEyes Display Pro to run Delta-E analysis on the calibrated screen. As the ColorWiki page on Delta-E states: “Delta-E (dE) is a single number that represents the 'distance' between two colors. The idea is that a dE of 1.0 is the smallest color difference the human eye can see. So any dE less than 1.0 is imperceptible (as in turn the lights off and head to the pub) and it stands to reason that any dE greater than 1.0 is noticeable (as in put the coffee on, we're going to be here a while). Unfortunately (and probably not surprisingly), it's not that simple. Some color differences greater than 1 are perfectly acceptable, maybe even unnoticeable. Also, the same dE color difference between two yellows and two blues may not look like the same difference to the eye and there are other places where it can fall down.”

We ran all of this software on an Intel Core 2 Extreme X9100-based 15” notebook, recording results via screen captures and notepad.

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Top Comments
  • 15 Hide
    nevertell , May 2, 2011 4:23 AM
    How about doing this with IPS panels ? :>
Other Comments
  • 3 Hide
    Anonymous , May 2, 2011 4:11 AM
    In the "Wrapping It Up" section, perhaps you meant "LED" instead of "LCD"?
  • 15 Hide
    nevertell , May 2, 2011 4:23 AM
    How about doing this with IPS panels ? :>
  • -8 Hide
    nforce4max , May 2, 2011 4:46 AM
    I am going to get such a monitor later this year. Imagine the leap from CRT to Led LCD.
  • 9 Hide
    Ragnar-Kon , May 2, 2011 4:47 AM


    I personally can't wait until the OLEDs manufacturing process becomes cheaper. Having seen Sony's new OLED displays at this year's NAB in Vegas, I can say they are VERY VERY impressive.
  • 1 Hide
    scook9 , May 2, 2011 5:04 AM
    I know that I have been rocking a pair of Gateway FHD2400's for a few years now and love them as they meet all my needs and have never left me wanting
  • 1 Hide
    g00b , May 2, 2011 5:12 AM
    Ummm ... LED? They are all LCD :) .

    "Ultimately, we’d pick LCD for media consumption, but we’d pick CCFL for editing work where detail and accuracy are paramount. LCD is more fun to watch; CCFL is more reliable."
  • -2 Hide
    Anonymous , May 2, 2011 5:17 AM
    Please substitute "LCD" with "LED" everywhere in the conclusion section!
  • -4 Hide
    theshonen8899 , May 2, 2011 5:20 AM
    Basically the differences are very dramatic right? I'm gonna sound like a hippie for this but I'd definitely go for the greener option. Just being polite for our future generation is all.
  • -2 Hide
    Anonymous , May 2, 2011 5:22 AM
    what g00b said. At the end you start saying LCD instead of LED, might confuse some poor soul.
  • 6 Hide
    wrxchris , May 2, 2011 5:35 AM
    May not be too relevant here considering that this article was based around image quality, but as a gamer, I'm still plenty satisfied with my trio of 25.5" Asus TN monitors. Yes, they bleed a bit of light around the edges and the colors may not be very accurate, but they handle fast moving images with no problems and only cost $750 for the set. And my favorite feature is the 16x10 aspect ratio, which is becoming quite hard to find these days; not sure why people are so willing to give up vertical screen space.
  • 5 Hide
    haplo602 , May 2, 2011 5:48 AM
    still does not beat a high quality CRT in image reproduction. size/weight/power are another thing.
  • -9 Hide
    pirateboy , May 2, 2011 6:02 AM
    if you check the evidence of osama's death on a ccfl screen you would discover he isn't really dead but it's just some random bearded dude they shot
  • 4 Hide
    Kisakuku , May 2, 2011 6:40 AM
    X-Rite's iMatch software doesn't have a correction for LED backlighting. A colorimeter like i1 Display 2 is not a spectrophotometer and can't just measure any screen thrown at it. It requires corrections for LED and WCG-CCFL backlighting. Not sure how you can make far-going conclusions from these inaccurate measurements.
  • 8 Hide
    LuckyDucky7 , May 2, 2011 6:50 AM
    HOW ABOUT SOME CHEAP IPS SCREENS?

    It's starting to look bad- if you're spending 200+ dollars you might as well be buying a REAL screen instead of these ones.
    Even 40 more dollars buys you a screen FAR superior to these crappy TN panels.

    So why aren't they being reviewed?
  • 4 Hide
    g00ey , May 2, 2011 1:15 PM
    It would be interesting to look at which LED lit panels use local dimming and which ones do not.
  • 4 Hide
    masterbinky , May 2, 2011 2:09 PM
    The funny thing in the opening of the article, it typically isn't the CFL that goes out in monitors. It is the power inverter, that powers the CFL. When I did dell repairs, it's funny they didn't let you just get the inverter to replace, you had to replace the whole panel.
  • 3 Hide
    masterbinky , May 2, 2011 2:17 PM
    nforce4maxI am going to get such a monitor later this year. Imagine the leap from CRT to Led LCD.

    I image it's a leap off a cliff. You'll be dissapointed if you place them side by side. Well, depending on what your looking at, but try a dark image with detail in it,hint: you'll have to use the CRT to identify that image. Black crush sucks.
  • -4 Hide
    mcd023 , May 2, 2011 2:21 PM
    great article. thanks.
  • 4 Hide
    bildo123 , May 2, 2011 2:44 PM
    I was going to make the switch from a 24" VA panel to a newer LED panel (in which I tried two). The first was an Acer LED 23" and the blue hue this thing put off was gross. It didn't how much I calibrated it the colors were dull and the blue hue remained. The next LED I tried was the Samsung BX2450, 24"; the colors were better and the blue hue was less noticeable but it was still apparent (at least to me). I realize both are TN panels as well but I think I'll wait it out until a nice LED-IPS panel comes out for sale in the States.
  • -3 Hide
    haftarun8 , May 2, 2011 2:45 PM
    @ masterbinky Have you looked at top quality IPS panel LCD's calibrated compared to a CRT lately? The HP LP2475w at work beats out an old NEC Multisync 22" CRT with darker blacks even though the whites are brighter, has very accurate colors after calibrating, and has zero black or white crush - every shade of extreme blacks and whites can be discerned on test images. If you don't want crap for LCD's you still have to spend over $500 for your monitor, no getting around it.
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