NEC MultiSync LCD1990SXi Solution Manual

Also see for LCD1990SXi BK MultiSync -LCD: Specifications White paper White paper User manual User manual

Color Accuracy -- Problems and SolutionsSince the inception of the PC in 1981 we have demanded more and more color. First color was usedto make games more interesting, and then to make programs easier to use. Color is now explodinginto most of your documents and presentations taking them to the next level of professionalism. Westarted out with 4 colors and moved to 8 then 16 colors. We graduated to capabilities as high as 256colors; and now we have rocketed into the stratosphere with 16 bit (65,000) and 24 bit (16.7 million)color. And all for what? More accurate and realistic representation of the world around us, or theworld we would like around us. We have now raised expectations for color reproduction on a PC tothe point where we as consumers are driving technology again. If you have ever tried to scan, createor print anything in color off a PC, you know the horrors that can creep up. Washed out images,colors askew if not actually wrong, and of course accuracy of gradients are just a few of the problems.We would like to first address some of the limitations and constraints of the color technologiescurrently available on the PC platform due to the technologies, and hardware, and then somesolutions. For some, this will be too technical for others, not technical enough. The intent is tointroduce new ideas to solve some of the problems that may be encountered.Keep in mind that this is going to be an arduous task. Some of the factors involved are ambient roomlighting, wall and ceiling color and reflectivity, video card, monitor, printer, software and scanner.This is all without mentioning the Red Green Blue to Cyan Yellow Magenta blacK conversionproblems. Then we have gamma correction, white balance, color temperature and phosphorchromaticity to take into consideration. Even considering this, we have to be aware of the gamma ofthe monitor, video card, scanner, printer and the image itself. With this many variables, one can seethat the likelihood of getting screen images that match printed output perfectly is slim if notimpossible. This would be a good time to explain several terms that are going to be used in thisarticle, and that you will see along your adventure in color calibration.GAMMAThe light output from phosphor is not linear to the video driving voltage. It is proportional to thevideo driving voltage raised to the power of "gamma". This means that brighter color is expanded anddarker color is crushed. In monitors and TVs gamma correction circuitry is included to minimize theeffect, thereby giving a truer representation of the video driving voltage input to the CRT. Thegamma figure given here is a corrected gamma function. Uncorrected gamma in phosphor tubes isusually 2.2. The closer the gamma is to 1 the "truer" the display.Formula: L=V^(gamma) ; light output = video driving voltage raised to the gamma.Gamma is typically written as just one number. For instance, for the NEC monitors, the gammastandard rating is: 2.46.