I am wondering if that is because the Bayer filters don't reach transparency at exactly the same wavelength and so a separation of "color" is possible because of a slight variation of reflected wavelength.
Yes that's right. In the Kodak sensors, all pixels are sensitive between 700-800nm, but the red pixels are strongest; the green ones are building steadily towards 800 nm while the blue ones stay lower but eventually come up rapidly; and from about 830nm onwards they are all equal, and responding like an unfiltered CCD.
That response then has to be multiplied by the spectral response of the IR-cut filter in your camera.
However the numbers fall, I like how it looks, with those warm brown tones.
Ray
