The eye\/brain mechanism for seeing is remarkable. We rely intensely on its ‘defects’ for home theatre. Consider a projector. It is casting an image onto a white screen. Yet with a good projector in a dark room, the black areas of the projected image look black. Clearly they must be white, because the ‘black’ is simply an area on the screen where no light is being projected. Or not much.<\/p>\n
If you are using a digital projector (LCD<\/a>, DLP<\/a> or LCoS<\/a>), if the scene fades out to black and you pause the picture, after a few seconds you’ll see that it’s not black at all, but a dark grey. That’s because no digital projector can yet full eliminate some light leakage. Yet even a small bright part appearing on the image can make the rest of the screen look dark, midnight black.<\/p>\n That’s because our visual circuits have a light intensity averaging system built in. The point of vision in the human animal is to facilitate recognition, not to act as a scientific instrument delivering lux counts. Our averaging system allows a black cat to look black even in bright sunlight, even though it is considerably brighter than a grey cat seen under modest artificial lighting. It is this averaging system that allows projectors to produce subjectively good images in our home theatres.<\/p>\n This post over at the ‘WILLisms’ blog<\/a> demonstrates the point clearly. Two squares are identical in grey level, yet one looks dark grey while the other looks almost white. Go and have a look. It is quite startling.<\/p>\n","protected":false},"excerpt":{"rendered":" The eye\/brain mechanism for seeing is remarkable. We rely intensely on its ‘defects’ for home theatre. Consider a projector. It is casting an image onto a white screen. Yet with a good projector in a dark room, the black areas … Continue reading