John et al, I might have referred to it before but there is an excellent documentary called "Cracking the colour code" that was produced in 2009 available on DVD. There are 3 episodes which cover some fascinating aspects of the experience of colour and citing some interesting experiments along the way. I particularly liked the one where they genetically engineered the cones in a monkey's retina to be responsive to a third colour and in dong so, providing the primate with the same or similar trichromatic experience that reproduces the effect of a complete spectrum in our brain. I wondered how long before they could give me x-ray vision like my childhood hero who had powers far beyond those of mortal men! Colour is further explored and described as a construct of the brain as we can only describe the electromagnetic radiation that stimulates our retina and generates the signals to the brain in terms of wavelengths that result from the vibration of subatomic particles known as photons. Just how remarkably adaptable this system is and how it has accommodated individual differences between humans is exemplified by the significant differences in the distribution of different colour sensitive cones between people. In other words, even though people have very different proportions of the red, green and blue sensitive cones distributed across the retina in a seemingly random arrangement we all tend to see colours as remarkably similar if not the same. This can only mean that the brain is 'massaging' the numbers and 'chromatically adapting' the signals it receives from the eye in order to achieve consistent perception of colour across the human race. If you lived long enough your brain may even compensate for the effects of macular degeneration. Unfortunately, MY brain seems to be degenerating faster then my eyes. Natural selection has a lot to answer for. You win some, you lose some. Mark On 28/07/2013, at 9:18 AM, John Castronovo <jc@technicalphoto.com> wrote:
Yes, the brain will adapt and do its best to give your vision a neutral white balance, however you're still looking through a filter (or not) which would have an impact on the relative brightness of different colors in the scene. Looking through yellowed lenses, blues will be darker and there will be less contrast within yellow objects. even though you may see a neutral color balance where grays are correct. For example, remove your yellow cataracts and you may notice the spots on aging skin more than you did before.
Cheers, John C.
-----Original Message----- From: Daniel Westcott Sent: Saturday, July 27, 2013 2:08 PM To: graxx@videotron.ca ; colorsync-users@lists.apple.com Subject: RE: Color Perception: How does coffee affect color perception?
I assumed most on this list were aware of such things. As we age or corneas yellow. This naturally serves as a yellow filter and affects our ability to see light of that wavelength. Our brains have an adjustment mechanism for this and indeed for light anomalies in general and, so to speak, turns up the gain on the filtered light to still give us white balance. .. these are our knobs like what you would find on an old school analog drum scanner to adjust for an unbalanced transparency. ..it's one of the most exciting parts of color science to me. Writing this from my phone but I'll see about writing more on this later. _______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/mark.stegman%40gmail...
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