This pages focuses on calibrating the CMS - the color management system of the BenQ HT2550 projector.
Essentially the calibration separately calibrates each of the primary and secondary colors - Red, Green, Blue, Cyan, Yellow and Magenta. What is this about? In a perfect world, a projected pure red would be just that, it wouldn't shift slightly to orange, purple, magenta, etc But reality is that the primaries and secondaries are not "on the money" As a result that affects all the color. I sometimes refer to calibrating the CMS "the last 10%" but it could be far more significant on some projectors, if they are off more than average before any calibration. -art
Delta E is a metric for understanding how the human eye perceives color difference. The term delta comes from mathematics, meaning change in a variable or function. The suffix E references the German word Empfindung, which broadly means sensation. Simply put, look at Delta E as a measure of grayscale/color accuracy. 3 and under is considered ‘Excellent’ and imperceptible by the human eye.