>Resolution doesn't apply to human sight as there are no pixels out there
Not true. The pixels in our eyes are the rods and cones in our retina. Most relevant to our discussion are the cones. The cones are all packed into a very densly packed array in a tiny pit in the retina called the fovea. I forget how densly packed they are, but what I do know is that there is some finite resolution; I remember writing down a number in class. But anyways, the fovea is the only place in your field of view with decent resolution. Try staring at one place on the screen, and see how many words you can read from that one spot. You will see that other than exactly at the center of your eye, you have pretty crappy vision!!
>32 bit color? maybe 128 bit color? 16 bit color?
Well, we don't have discrete, digital color detectors in our eyes. Think of a throttle, rather than a gear selector. Though our photoreceptors themselves are analog detectors, our ability to PERCIEVE the differences in light intensity and color saturation may have some limits. Color detection is achieved by there being 3 different types of cones in our eyes: red, green, and blue cones. For every "pixel" in our eye, there is one each of red, green, and blue cone. These all synapse onto a horizontal cell, which integrate the three inputs into one output. So just as each pixel on your screen contains a red, blue, and green beam, each pixel in your eye receives red, blue, and green information.
The color depth that we can see is unrelated to the color depth that your graphics card gives you. From what I understand, the purpose of all that stuff is to create a palette that contains the most common colors on a given screen. So let's take 256 colors for example. If you were to try to view a Monet at 256 colors, the graphics card would decide what 256 colors are most common in the picture, and only display those. So lots of subtle differences would be blended into each other. So the purpose of having millions of colors is to have as large a palette as possible, so as not to miss any of the subtle differences. We have an infinitely large palette; that is, how colorful an object is does not decrease our ability to percieve the differences in the colors, unlike graphics cards. Our brains are excellent computers, better than we often give them credit for!!
Refresh rates are dependent upon the speed of nerve impulse propagation from the photoreceptors to the cells they communicate with. But even this is not a limiting factor, since while one photoreceptor is "worn out", there are plenty of inactive photoreceptors around it which can "take up its slack". The flicker that you see when you wave your hand in front of a flourescent lamp is from the lamp itself. Try doing that with an incandescent lamp - no flicker.
Here is something new to add to the thread:
Have y'all ever thought of the concept of "qualia"? This is the notion that visual experience varies from one person to the next, so that maybe what you call blue I would call green, but simply because we have agreed upon the names of the different colors, we assume that everyone sees the same way we do. This is a question that cognitive scientists love to talk about.
John Kim
Johns Hopkins University
Neuroscience, BA '01