The Color Challenge
For several years, the sleek good looks of LCD monitors have been tempting Mac users away from clunky CRT displays. And LCDs have other advantages over traditional CRTs: they're flicker free, which can prevent eye fatigue; they're much brighter and can display a wider dynamic range; and their colors don't drift. And the average price of an LCD-formerly several times that of a CRT-is dropping.
Some companies, including Apple and SGI, claim that their LCDs' brightness and stability make them ideal for the color-critical work of graphic designers, professional photographers, and high-end-scanner operators. These claims could not be tested until the recent arrival of LCD calibration and profiling tools. Armed with these tools, Macworld Lab and I cast a critical eye on three LCDs and two CRTs to determine which technology offered the most-accurate color.
We started with two 22-inch CRT monitors that come with calibration hardware and software: the $3,499 Personal Calibrator V, from Barco, and LaCie's $1,099 electron22blue with its $499 color calibrator, blue eye. Of the three LCDs we tested, only the $2,999 Apple Cinema Display and SGI's $1,495 Silicon Graphics 1600SW are strictly digital monitors. (Some LCDs convert a computer's digital signal to analog current, which can result in visible distortion and a loss of sharpness. The digital signal drives the Apple and SGI displays we tested, thus avoiding these problems.) We also tested the $1,899 NEC MultiSync LCD 1800-not because NEC claims that it's similar to the Apple and SGI monitors we examined, but to see how an analog LCD would compare with digital models.
To judge the monitors' performance, we compiled the subjective opinions of a five-person jury and made extensive measurements (for the details of our testing methodology, see "How We Tested").
Tools of the Trade
Graphic designers and other professionals who need to make critical decisions about tone and color rely on well-calibrated displays. Calibration and profiling tools for CRT monitors, such as ColorVisions' $399 OptiCal and $224 PhotoCal (800/554-8688, www.colorcal.com ), are mature and relatively inexpensive. But LCDs present some challenges. The suction-cup colorimeters designed to measure a CRT's color accuracy can rip the coating from the front of LCD screens. And the software routines for building CRT monitor profiles don't work well with LCDs.
Color-measurement giant GretagMacbeth (800/622-2384, www.gretagmacbeth.com ) recently began selling a $200 harness that allows you to attach the company's $3,750 Spectrolino spectrophotometer to an LCD, and the company has updated its $3,500 ProfileMaker Pro software to include a calibration and profiling routine tailored to LCDs. When we did our testing, the harness was the only LCD-calibration option; however, in April of this year, the company announced the Eye-One Monitor, a $600 package that includes a measurement device and software; it creates profiles for LCDs and other monitors. (For more about calibration, see "Calibrating Monitors.")
So, in theory at least, we now have the means to replace bulky CRTs with slim LCDs, even when our bread and butter depends on accurate on-screen color.
Test Results: Color Me Critical
Some test results surprised us. Unlike CRT monitors, LCDs have always had problems with viewing angles-tone and color shift as you view a display from different angles. But the Apple Cinema Display had an impressively wide viewing-angle range, better than that of the Silicon Graphics 1600SW and much better than that of the MultiSync LCD 1800.
I Love a Monitor in Uniform The Cinema Display didn't fare so well in display uniformity. In fact, for all three LCDs, our jurors' eyes and our spectrophotometer told the same story: the displays' screens lacked uniformity and had obvious light and dark spots. This lack of uniformity has a direct impact on a display's accuracy because the same color looks different depending on its location on the monitor. Both CRT monitors had excellent uniformity.
When we used a GretagMacbeth Spectrolino to take a set of nine readings across the monitors' faces, we found that the Personal Calibrator V had the best uniformity, followed by the electron22blue, with a maximum of 3 and 3.8, respectively (1 is the smallest perceptible color difference, 3 is a strict goal for profile accuracy, and 6 is usually considered a good commercial match in the print trade). The Cinema Display had a of 6.7, followed by the NEC MultiSync LCD 1800, which had a of 7.1. The Silicon Graphics 1600SW had the worst uniformity, with a of 7.4.
These results point to a flaw in LCD technology. All the light produced by an LCD comes from the backlight-the LCD elements simply act as color filters. It's hard to illuminate an LCD evenly, and the bigger the display, the more difficult it is. Apple deserves kudos for making the Cinema Display as good as it is, but its uniformity still falls short.
Test Results: Color Accuracy
We gauged the monitors' color-display accuracy with a Macbeth Color Checker, a color target from GretagMacbeth with a grid of 24 color swatches (see "Macbeth Color Checker"). Jurors compared the physical target in a light box with the on-screen display of the same target.
The LCDs reproduced the yellow swatch (row 3, column 4) from the Color Checker better than the CRT monitors (which gave it an orange tinge), but for almost all other colors, our jury felt that the CRT monitors were more faithful to the original. They pointed out that the blacks on the LCDs were washed out compared with both the CRT blacks and the physical target, and that the tracking of the gray patches (row 4) was much better on the CRTs.
The jury unanimously picked the Barco monitor as the most accurate, followed by the LaCie (though a lone dissenter placed the Apple display second). The Apple display came in third, followed closely by the NEC (one juror said it looked just as good as the Apple), with the SGI monitor coming in dead last.
Apple and SGI claim that their LCDs particularly suit color-critical work. Both companies say their LCDs are much brighter than CRTs and hence have a wider dynamic range (the range from black to white). This was certainly true of the Apple and SGI LCDs in their raw, uncalibrated state: the Cinema Display achieved a white luminance of around 180 candelas per square meter (cd/m 2 ), while the smaller Silicon Graphics 1600SW put out in excess of 200 cd/m 2 . In comparison, the uncalibrated LaCie display had a white luminance of 158 cd/m 2 . Barco monitors are calibrated at the factory to a conservative 75 cd/m 2 so they can maintain calibration aim points for three years.
Calibration always reduces the brightness of any monitor from what it is in its raw state. After calibrating the LCDs with the Spectrolino, we noticed a dramatic decrease in brightness: 108 cd/m 2 for the Apple display and 98 cd/m 2 for the SGI. We achieved a calibrated white luminosity of 103 cd/m 2 on the LaCie with plenty of headroom; however, we wonder how long it could maintain that target luminance. When you also factor in the relatively weak blacks of the LCD monitors, the contrast range in their calibrated state differs little from that a good CRT's.
Resolution Differences Apple and SGI also point to the 1,600-by-1,024-pixel resolution of their LCD monitors as superior to a CRT's resolution. We ran both CRT monitors at a resolution of 1,600 by 1,200, which displays approximately 15 percent more pixels than the LCDs do, and didn't see any unacceptable softness or other display artifacts.
The Last Word
I can't recommend any of the LCD monitors we looked at for color-critical work because their test results were relatively poor. But even if they had tested well, the cost of LCD monitors would make them a poor choice for many graphics professionals.
CRTs are far from ideal. Most of us would love to have a stable, flicker-free display that took up little space on our desks and was light enough to lift with one hand. But until the uniformity of LCDs starts to approach, if not equal, that of CRT monitors, graphics professionals shouldn't say goodbye to the devil they know.
BRUCE FRASER is a coauthor of Real World Photoshop 6 (Peachpit Press, 2001). He soft-proofed the book on his Barco CRT monitor. Photography by Stan Musilek.LCDs may be prettier than Crts but are they as precise? Read about our test results. Macbeth Color Checker: You can use this reference card with 24 swatches to evaluate the accuracy of color reproduction. Thin Isn't In: The Apple Cinema Display (left) meets the Barco Personal Calibrator V.
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