Re: Bears and Butterflies

[joneil@xxxxxxxxxxxxxxxx (Joseph O'Neil)]

boblong@xxxxxxxxxxx (Robert Long) writes:
> |Don't know about this.  The eye doesn't see blue very well so perhaps
> |the red is an optical illusion?
> 
> Presumably it is, but I wish I understood the mechanism more clearly.
> I've never even had confirmation from any other subway rider that
> others see the red/blue bulbs as I do.  Perhaps my own (slight)
> astigmatism is a factor.  But I saw it as a kid, before I wore
> glasses, and continue to see it now, with astigmatism-corrected
> bifocals.


  Hopefully not moving too much off topic here, but I recently underwent 
a very extensive 2 hour test for colour blindness at a nearby university.

  I had discovered I was colour blind in my early twenties when I took 
flying lessions and was given a colour test then.  Problem with the 
"standard" colour vision test used around the world is it's like using a 
shotgun to kill a mouse - effective but very crude.

 I'll get to the point of this in a minute.

  What my particualr colour test told me was this: I am colour blind 
right accross the spectrum.  Not toally - i can see colour fine in bright 
sunlight.  Imagine turning down the colour setting on a television half 
way between "normal" and total black and white.  That's aobut where I am.

  Now this is where it gets interesting and revelant to the statements 
above.

  As it was explained to me, in dim, artificial or other possible 
situations, my brain is not receiving enough information to process the 
image I am seeing, therefore it , for lack of better words, makes it best 
guess.  In other words, in dim light you might see a sweater as green, 
but I see it as blue.  I actually "see" the colour blue, because that is 
how my brain is processing the information.

 There was a famous experiment done years ago where test subjects wore 
glasses that had prisims that inverted everything upside down.  After a 
period of time, the brains of the test subjects had adapted and inverted 
the image right side up.

  Point is - our brians are the world's most complex image processing 
systems int eh world.  Often our brians have some sort of preconcieved 
idea of what should be "normal" when we look at things.

  Now it my case it is more extreme than the norm.  However, every person 
under certian particular circumstances can be "fooled" into seeing 
something differnt form how it really looks.

  So, for our friends here discussing how/why and object can look a 
particular way at one time and not at another or not too other people, it 
is simply a matter of how your brain is processing the image.  Any for of 
form of defect in your eyesight - from poor lighting to cataracts to 
colour blindness, etc, will cause your brain to try and compensate for 
that lack of information.

  Weird and neat, eh?

  A little back on topic, one of the reasons I love IR is that in some 
ways it is not much different from colour photography for me - both 
capture an image I cannot see with my own eyes.
later all
joe


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Topic No. 18