What Colour is an Orange in the Dark:

Discussion in 'General Science & Technology' started by paddoboy, Sep 17, 2015.

  1. paddoboy Valued Senior Member

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    Thanks, Interesting. Perhaps your example of the Moon on the horizon at see, maybe another example of what the brain has conceived as "convention"
    Or perhaps again, the size argument is in relation to the stars?
     
    Last edited: Oct 15, 2015
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  3. paddoboy Valued Senior Member

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    I remain unconvinced and offer sideshowbob's explanation as rather relevant.
    Dreams are dreams are dreams......I don't know why we dream....My dreams as "real"sometimes as they seem, are still indistinguishable as far as colour is concerned. I have dreamt of being Superman....What I do surmise is that dreams are an exaggeration of everyday experiences and observations.
    I don't believe to much credence can be put into what people dream.
     
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  5. paddoboy Valued Senior Member

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    I'm saying, and am of the opinion that EMR/Light is needed in the first instance. Without light/EMR, anything else is null and void.
     
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  7. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    We will just need to agree to disagree - I know I dream in color and can have the sensation of green, a dark shade, just by recalling my first car with my eyes closed.

    One of the most vivid sensations I can reproduce / recall with eyes closed is the color and hissing sound of St. Elmos Fire at the top of a sail boat's mast one night at least 50 years ago. As I understood what caused it - an electric field so intense it was ionizing the air - a strong risk of a lightning bolt that could kill me, I was so scared that I prayed with real conviction. Intense emotion really "etches" their memories deeply into memory.
     
    Last edited: Oct 15, 2015
  8. paddoboy Valued Senior Member

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    What I was trying to say there, was the brain is not perfect.....and neither is everyone's physiological makeup and biology....faults do exist such as colour blindness.
    But in that first instance, we need EMR/Light to take advantage of the reflective properties of an object and how the brain interprets that.
    My example again: I put an object in a complete darkened room and ask you to tell me the colour of it.

    I try and approach any matter with no bias except the scientific method and appropriate peer review. In this case, maybe I do have a bias as in the many many thousands of replies to this question over a number of threads in the past now defunct forum, with many professional experts including Medical people [at least two] Astronomers, GR theorists, professional Physicists, a Philosopher or two, Billy's aspect was never [from my memory] raised at all.
    Although again, I must say I never took part in the first couple of threads, as it was too mundane a subject for my liking.

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    I do believe my position on that is pretty clear.

    Billy's position and reasoning as I said, is something fairly new to me.
    In summing, in my opinion...The colour of anything depends on....
    [1] The EMR/Light falling on an object.
    [2] The reflective properties of that object.
    [3] How an imperfect organ like the brain and associated neurons etc interpret whatever is reflected to your eyes

    Perhaps.
    I was going to get a definition of colour and came upon the following WIKI article which imho best describes what I believe to be most factual.............


    Color, or colour (see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, blue,yellow, etc. Color derives from the spectrum of light(distribution of light power versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects or materials based on their physical properties such as light absorption, reflection, or emission spectra. By defining a color space colors can be identified numerically by their coordinates.

    Because perception of color stems from the varying spectral sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully explain thepsychophysical perception of color appearance.

    The science of color is sometimes called chromatics, colorimetry, or simply color science. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what we commonly refer to simply as light).
     
  9. paddoboy Valued Senior Member

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    I spent 4 months at sea travelling on a three masted Square rigged Barquentine in 1974, from Panama to Sydney, and although we ran into two storms one with winds gusting to force 9, I was never lucky enough to experience "St. Elmos Fire"

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  10. paddoboy Valued Senior Member

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    Off topic I know but my time on the Barquentine was the best 4 months of my life....

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    http://thanetonline.blogspot.com.au/2007/12/friggin-in-rigging.html
     
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  11. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    What that means in humans is that there is neural activity in two "orthognal" nerves sets in the V4 region of the brain One is the blue yellow axis and the other is the red green axis.

    Yes humans have many qualia - pain is one, as is distinct color sensations, or anger, hunger, etc. There is only neural activity creating these qualia. Nothing extermal required but there may be, just as EMR may be the cause of color sensations, but need not be.

    For example sciatic leg pain is a creations of the brain in response to a "pinched" spinal cord nerve, usually. As that nerve normally is conveying information about conditions in the leg, the brain refers the location of the pain to the leg, not where something is wrong. - the spinal cord.
     
  12. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Were you ever able to see the "green flash" just after the sun sets? I have tried several times - why I was in a sail boat after dark far out in the ocean* when I experiences St. Elmo's fire for a couple of minutes.

    At work at APL/JHU a Ph.D. colleague had had years at sea during his "navy years." He had known where and when to look and seen the green flash twice! It only last for a fraction of a second and only under unusually atmospheric conditions near the sea surface.

    * As less than a meter or so above sea level I was too far east in to the Atlantic to see anything but a sea surface horizon - you need that. - Can't see the the green flash when on land. Also I only tried when the weather was promising for the green flash. Not much wind - that too is required - so it took a long time to get back to port. I could see and sail by the stars, but had a compass with me in case it clouded over.
     
    Last edited: Oct 15, 2015
  13. paddoboy Valued Senior Member

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  14. paddoboy Valued Senior Member

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    This be her! Arrrr me hearties!

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  15. paddoboy Valued Senior Member

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    Dead reckoning.
    On clear bright nights I often took sightings on the Moon [not that accurate] and Venus and Jupiter, along of course the Sun in the day time.
    I became quite enthralled and captivated by comparing my calculations and positions and fixes with the first mate and Skipper's work.
    I was always trying to improve my accuracy and was disappointed when all my sightings and fixes were never spot on with the official log.
    The Skipper took me under his wing and noticed that all my calcs and consequent positions and fixes, were a constant 3 miles further back than the official log. He concluded that I probably had an error in my eye sight, and gave me great comfort in informing me that such a constant "unavoidable" error could be allowed for if I was ever skippering my own vessel.
    [We had two sextants on board, the official bronze one worth a couple of thousand bucks, and a plastic one, which gave just as good results, although more care needed to be taken to keep it precise and accurate].

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  16. Write4U Valued Senior Member

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    What I have not seen mentioned is that some colors actually change at the molecular (or smaller) levels.

    I was surprised to learn that at the nano level the actual color of matter may be different.
    https://en.m.wikipedia.org/wiki/Glass_coloring_and_color_marking

    Think of all the gold contained in all the stained glass-in-lead windows of churches.
    it is also demonstrated in this NOVA presentation

    ( @ 36: 45)
     
    Last edited: Oct 16, 2015
  17. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    More precisely stated: the coefficient of reflection (and transmission & absorption) can change. Gold is the most malleable substance. It can be beaten to be a foil only a few molecles thick. Its optical coefficients then let t, the transmission coefficient be non zero -especially for the shorter wave length - If the sun is viewed thur a thin gold foil, the sun appears green. Always true is t+a+ r = 1.

    Regularly spaced small scratches on reflective surface make diffraction grading. I.e. the reflection coefficient becomes very low for most angles and quite high for one (or two).
     
  18. sideshowbob Sorry, wrong number. Valued Senior Member

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    Can a person who was born blind "imagine" the colour orange without ever having experienced the EMR?
     
  19. John Connellan Valued Senior Member

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    Maybe they could. Depends on why they are blind of course. If the defect is restricted to only parts of the eye, perhaps spontaneous signals from color receptors could still fire from the brain making them sense orange. Whether or not the mind can imagine color without having ever experienced the signals is an even tougher question!
     
  20. sideshowbob Sorry, wrong number. Valued Senior Member

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    That's the question I'm asking.

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  21. John Connellan Valued Senior Member

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    Thought it might have been alright

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    Just clarifying that there can be different types of blindness.

    I certainly can't answer it anyway!
     
  22. Write4U Valued Senior Member

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    There are people who are sighted but in addition to seeing colors, their visual network is also connected to their olfactory network and they can also smell the color they see.

    But I cannot imagine how a "blind" (lack or damaged optical nerves) can see anything at all, let alone the color of a thing. But here again the brain has compensated and in certain individuals echolocation can produce a mental image of the external world.

    I saw a presentation of a totally blind man going for a bycicle ride everyday on a narrow path, constantly making a clicking sound which guided him unerringly along the curved path.
     
    Last edited: Oct 16, 2015
  23. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I doubt they could. Even some electrical stimulation of area V4 probably would not cause any color experience - certainly not if that area had been developed for other processing - the brain of a young person is very flexible - "plastic."

    This is a very interesting question. Thank you I have read many (more than a dozen) papers on "color blind Mary" or "black & white Mary" and none* considered that her V4 may have been cooped for some non-color processing task - a huge oversight IMHO. She is a very important hypothetical case in the discussion of "knowledge."

    * Most are by philosophers and many of them are quite ignorant of human visual neuro anatomy. I know a great deal about that despite having forgotten more than half of what I once knew. I am sort of embarrassed it took your question to make me think of this important item missing in all the papers I have read about Mary.
     
    Last edited: Oct 17, 2015

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