From: “Colour, Why the World Isn’t Grey” by Hazel Rossotti
June 17th, 2006 | No Comments »Reading Hazel Rossotti’s “Color, Why the World Isn’t Grey” (Princeton University Press).
From Chapter 14, “The Eye and the Brain”, p.130
She writes, referring to an earlier collection of selected writings from Newton, Goethe, DaVinci, etc. (”Sensations of Colour” pp104-107):
“…..how can we reconcile the phenomena they describe with our earlier interpretation of colour vision in terms of the absorption of photons by the three cone pigments?”
It is obvious from my explanation for light interaction with the retina that the eye evolved to detect the wave nature of light. It is the absorbing mass of the cone and rod retinal receptors that act as quantized electron (’nanowire’) sites thus preserving the quantum nature of the interaction. This interacton can (and should) be properly termed a ‘quantum interaction’ and avoiding the mental construction that ‘photons interact with pigment molecules’. The retina is actually a precise, geometrically spaced, array of receptor nanowires with the sub-optical wavelength spacings between them acting as tuned optical ‘antennas’. A great deal follows from, and is explained by, this realization..
A very prescient comment by Rossotti on p.130:
“Some of the psychological responses to colour may have a simple geometrical origin.”
The emphasis is mine. The author refers here to a number of visual responses that indeed support my explanation but, I am afraid that her basic premise is just more of the mistaken model
For example, an exaggerated longitudinal chromatic aberration (LCA) is used (Fig. 51) to explain why
“A red splodge often seems to advance from the page and to concentrate the viewers attention towards its centre, a blue splodge seems to recede and lead the eye outwards”.
The figure seems to say that a different focusing condition brings only one of the three RGB wavelengths to focus on the foveal region of the retina. Does this imply that one could see only one of these wavelengths at a time? How extraordinary! But she does for some reason introduce chromatic aberration – that in my explanation is not an ‘aberration’ at all but central to the vision process.
Again to review, I propose that the eye basically functions to continually bring the long (R) wavelength to focus on the fovea. The ‘aberrated’ (I would say simply ‘refracted’) GB wavelengths simultaneously (or almost simultaneously) impinge on the parafoveal region of the retina with the exact center of the RGB band incident at 7-8 degrees of retinal angle. The hues of color that the author wants to see is determined by comparing intensities on either side of this point (I tire of pointing out that this is what Edwin Land deduced)
Again, the unspoken but crucially important implication of the Figure is that the retina (or fovea) is the location or plane where the image formation process of the eye takes place. One imagines, as those espousing the existence of ‘RGB cone mosaics’ seem to believe, that this region is the analogue of the silicon receiver in a digital camera or film in a camera. formng the (intensity only) image. This is not the case at all as I explain.
In Figure 52 the author demonstrates how blue tends to be perceived in peripheral, and red in central, vision. I have written about this (see previous Comments) and it is inherent in my explanation.
The author on p.141 does provide a clear explanation of Land’s initial color vision experiments. For those who have forgotten I will transcribe directly from her text:
“A similar effect has been exploited by Land, who showed that red and white light could be mixed in such a way as to give sensations over a wide range of colours. He made black and white transparencies, photographing each scene twice, once through a red filter and once through a green one. He projected them both on to a screen, the first with a red light, and the second with a white one, and when the images were superimposed, obtained, in addition to red and black, a range of colours from turquoise ,through green and yellow to orange.”
GCH
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