The world's most perfect calibration instrument cannot measure how our brain interprets what our eyes see. Some attempts have been made to emulate how humans perceive light but science has yet to produce an instrument which tells the whole story. SMPTE's human factors work resulted in their Recommended Practices document #166: "Critical Viewing Conditions For Evaluation Of Color Television Pictures." This is the work from which 6500K bias lighting is taken. The document actually devotes much more attention to color perception than eyestrain. Here are some links that dramatically demonstrate how ambient lighting and surrounding surface colors in the room can cause us to think we see better black levels and/or distorted colors that aren't really in the image. http://www.echalk.co.uk/amusements/O.../illusions.htm (Note particularly the "Colour perception" and "Colour perception 2" demonstrations.) http://www.lottolab.org/ (enter the "lab," click the "Illusions" button and note particularly the "Brightness" demonstrations.) http://www.lottolab.org/articles/illusionsoflight.asp (new and quicker link) Professional monitor environments, where critical image analysis is conducted for mastering video programs, use tightly controlled lighting and neutral surfaces surrounding the display. The demonstrations above make very clear the importance of incorporating similar room conditions if image fidelity is desired. This material also makes abundantly clear how destructive to image fidelity the Philips 'Ambilight' colored light features really are. Human visual perception is seldom sufficiently understood when consumer, and even many professional, display systems are designed and implemented. Since our human vision is so adaptive, we can think we perceive a "natural looking" image but actually do not if viewing environment conditions are incorrect. The demonstration material at the links above should provide considerable practical reinforcement for folks who have a hard time being persuaded by the theory alone or decades of imaging industry professional practice. If you think there is some trick being used in the online images, try printing out the demonstration patterns and making your own paper masks. You will see that the only "trick" involved is being provided by your own brain. This is why even a perfectly aligned display device can indeed look different than the calibration report says. Conflicting viewing environment conditions, such as the wrong lighting or colored room surfaces within the observer's field of view, will ALWAYS distort how a video image appears. No calibration instrument can measure this function of the brain. This technical article goes into more detail about practical applications for this topic: http://www.cinemaquestinc.com/ive.htm . Best regards and beautiful pictures, G. Alan Brown, President CinemaQuest, Inc. "Advancing the art and science of electronic imaging"