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http://nfggames.com/games/ntsc/visual.shtm
Summary: You really don't see blue very well.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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From: nemesis
Subject: Re: Very interesting color resolution examples
Date: 26 Apr 2009 14:29:26
Message: <49f4a806@news.povray.org>
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Darren New wrote:
> http://nfggames.com/games/ntsc/visual.shtm
>
> Summary: You really don't see blue very well.
Would that still hold true in a blue-shaded scene? :P
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On 4/26/2009 11:40 AM, nemesis wrote:
> Darren New wrote:
>> http://nfggames.com/games/ntsc/visual.shtm
>>
>> Summary: You really don't see blue very well.
>
> Would that still hold true in a blue-shaded scene? :P
Give it a try and post the resulting images. I'm betting that, yes, it
would still hold true.
--
...Chambers
www.pacificwebguy.com
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"nemesis" <nam### [at] nospam-gmail com> wrote in message
news:49f4a806@news.povray.org...
> Darren New wrote:
> > http://nfggames.com/games/ntsc/visual.shtm
> > Summary: You really don't see blue very well.
> Would that still hold true in a blue-shaded scene? :P
http://nfggames.com/games/ntsc/traci_blue3.png
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From: nemesis
Subject: Re: Very interesting color resolution examples
Date: 26 Apr 2009 17:50:05
Message: <49f4d70d@news.povray.org>
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somebody wrote:
> "nemesis" <nam### [at] nospam-gmailcom> wrote in message
>> Would that still hold true in a blue-shaded scene? :P
>
> http://nfggames.com/games/ntsc/traci_blue3.png
Funny, but you know that's just a component.
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Chambers wrote:
> On 4/26/2009 11:40 AM, nemesis wrote:
>> Darren New wrote:
>>> http://nfggames.com/games/ntsc/visual.shtm
>>>
>>> Summary: You really don't see blue very well.
>>
>> Would that still hold true in a blue-shaded scene? :P
>
> Give it a try and post the resulting images. I'm betting that, yes, it
> would still hold true.
Well, turns out it's true, yes:
http://www.fileshost.com/download.php?id=BF214D771
It's a gimp file with a decomposed image of a bird in additive layers.
You may select which ones to view.
Very counter-intuitive. OTOH, it's kind of comforting it is not in our
nature to feel blue. ;)
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From: somebody
Subject: Re: Very interesting color resolution examples
Date: 26 Apr 2009 18:20:23
Message: <49f4de27@news.povray.org>
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"nemesis" <nam### [at] nospam-gmailcom> wrote in message
news:49f4d70d@news.povray.org...
> somebody wrote:
> > "nemesis" <nam### [at] nospam-gmailcom> wrote in message
> >> Would that still hold true in a blue-shaded scene? :P
> > http://nfggames.com/games/ntsc/traci_blue3.png
> Funny, but you know that's just a component.
It may be a component, but it also is an _image_ with only blues...
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From: scott
Subject: Re: Very interesting color resolution examples
Date: 27 Apr 2009 02:37:54
Message: <49f552c2@news.povray.org>
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> http://nfggames.com/games/ntsc/visual.shtm
>
> Summary: You really don't see blue very well.
I wonder if it is more that you don't see *colour* very well compared to
brightness, not blue compared to green? It just so happens that the green
channel carries almost all of the brightness information compared to blue.
To test this out you could split into Yuv colour space (or similar) and
reduce the resolution of the u and v channels, I suspect then you could get
away with compressing green colours just as much as blue ones, so long as
the Y (brightness) channel remained at the original quality.
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"scott" <sco### [at] scottcom> wrote:
> > http://nfggames.com/games/ntsc/visual.shtm
> >
> > Summary: You really don't see blue very well.
>
> I wonder if it is more that you don't see *colour* very well compared to
> brightness, not blue compared to green?
I remember once seeing the sun's power spectrum compared to the eye's response
spectrum, possibly at uni. The eye's spectrum follows the sun's very closely -
not suprising considering we evolved under its glare. This of course means that
we are far more sensitive to green light than red or blue, which are at the far
extremes of the visible range. I can't seem to find any refs for this
comparison, but there is a phototopic luminosity function on w'pedia:
http://en.wikipedia.org/wiki/Luminosity_function
....so this probably isn't cutting-edge news... still interesting to see it
demonstrated this way though.
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>> >> Would that still hold true in a blue-shaded scene? :P
>
>> > http://nfggames.com/games/ntsc/traci_blue3.png
>
>> Funny, but you know that's just a component.
>
> It may be a component, but it also is an _image_ with only blues...
And hence is much much darker than an image with only greens.
Try adjusting the brightness of the green one to match the blue (I found
multiplying by 0.3 did it here), then compare side-by-side, now there's not
so much visible difference...
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From: Orchid XP v8
Subject: Re: Very interesting color resolution examples
Date: 27 Apr 2009 16:48:25
Message: <49f61a19@news.povray.org>
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Darren New wrote:
> Summary: You really don't see blue very well.
Gee, do you think this could be somehow related to the fact that only 7%
of the light receptors in your eye are tuned to blue?
Actually, you know what? Screw that... Where can I find this "Traci"??
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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"Bill Pragnell" <bil### [at] hotmailcom> wrote:
> I remember once seeing the sun's power spectrum compared to the eye's response
> spectrum, possibly at uni. The eye's spectrum follows the sun's very closely -
> not suprising considering we evolved under its glare. This of course means that
> we are far more sensitive to green light than red or blue, which are at the far
> extremes of the visible range.
Just pondering that evolutionary adaptation is fascinating. I wonder if it came
about from the fact that we descended from tree-or-forest-dwelling animals,
where the predominant color was green? Not that the *entire* earth was
forested, but a good portion of it. Does it also mean that we humans can now
see subtle gradations of green better than subtle gradations of red or blue?
KW
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> Just pondering that evolutionary adaptation is fascinating. I wonder if it came
> about from the fact that we descended from tree-or-forest-dwelling animals,
> where the predominant color was green? Not that the *entire* earth was
> forested, but a good portion of it. Does it also mean that we humans can now
> see subtle gradations of green better than subtle gradations of red or blue?
The question is... why are leaves green in the first place? Wouldn't
they work so much better if they were black??
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> Just pondering that evolutionary adaptation is fascinating.
http://www.sciam.com/article.cfm?id=evolution-of-primate-color-vision
Might be of interest...
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From: John VanSickle
Subject: Re: Very interesting color resolution examples
Date: 28 Apr 2009 07:31:26
Message: <49f6e90e$1@news.povray.org>
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Orchid XP v8 wrote:
> Darren New wrote:
>
>> Summary: You really don't see blue very well.
>
> Gee, do you think this could be somehow related to the fact that only 7%
> of the light receptors in your eye are tuned to blue?
>
>
> Actually, you know what? Screw that... Where can I find this "Traci"??
I think it's a given that if the list of links at the bottom had one to
more pix of Traci, that link would get the lion's share of the hits.
Regards,
John
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Kenneth <kdw### [at] earthlinknet> wrote:
> [-- text/plain, encoding 8bit, charset: iso-8859-1, 17 lines --]
> "Bill Pragnell" <bil### [at] hotmailcom> wrote:
> > I remember once seeing the sun's power spectrum compared to the eye's response
> > spectrum, possibly at uni. The eye's spectrum follows the sun's very closely -
> > not suprising considering we evolved under its glare. This of course means that
> > we are far more sensitive to green light than red or blue, which are at the far
> > extremes of the visible range.
> Just pondering that evolutionary adaptation is fascinating. I wonder if it came
> about from the fact that we descended from tree-or-forest-dwelling animals,
> where the predominant color was green? Not that the *entire* earth was
> forested, but a good portion of it. Does it also mean that we humans can now
> see subtle gradations of green better than subtle gradations of red or blue?
No, it's because of the surface temperature of the Sun. Both leaves and
best vision is at the green amplitude for a common reason.
--
- Warp
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Invisible wrote:
> The question is... why are leaves green in the first place? Wouldn't
> they work so much better if they were black??
Leaves are green because water passes green light (to a first approximation).
First plants evolved just below the surface of the water, with purple (red
and blue) color. I.e., the first plants absorbed the abundant green color
while reflecting both the infrared and ultraviolet that was dangerous. You
still see some plants and most photosynthetic anaerobic single-cell
organisms with this coloring. It's also the stuff in your eyes that lets you
see better after 10 minutes in the dark.
Then oxygen-creating photosynthesis evolved in bacteria that lived *under*
the layer of purple algae, which absorbed the purple reflected from that
algae, and hence looks green.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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Warp wrote:
> No, it's because of the surface temperature of the Sun. Both leaves and
> best vision is at the green amplitude for a common reason.
If green was the best color for light absorbtion, the leaves wouldn't be
*reflecting* green. :-)
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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"scott" <sco### [at] scottcom> wrote:
> > Just pondering that evolutionary adaptation is fascinating.
>
> http://www.sciam.com/article.cfm?id=evolution-of-primate-color-vision
>
> Might be of interest...
Cool! Thanks for that. I need to get that issue of SCIENTIFIC AMERICAN; not
only does it discuss this very topic, but also 'dark energy.' Being a closet
cosmologist at heart, the issue should keep me fascinated for weeks!
KW
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I wonder why WE can't see into the ultraviolet (and the infrared?) That
SCIENTIFIC AMERICAN article points out that some existing creatures can see at
least somewhat into the UV spectrum. So their retinas(?) must have developed
some kind of protection that we don't (currently!) have. "Man is the superior
being.": Bah, humbug.
And if we could see into the infrared, then Traci would be looking *oh* so much
nicer. ;-P
KW
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"Kenneth" <kdw### [at] earthlinknet> wrote:
> And if we could see into the infrared, then Traci would be looking *oh* so much
> nicer. ;-P
You might say she'd be looking even hotter.
;-)
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From: Le Forgeron
Subject: Re: Very interesting color resolution examples
Date: 28 Apr 2009 16:29:18
Message: <49f7671e@news.povray.org>
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Le 28/04/2009 18:14, Darren New nous fit lire :
> Warp wrote:
>> No, it's because of the surface temperature of the Sun. Both leaves and
>> best vision is at the green amplitude for a common reason.
>
> If green was the best color for light absorbtion, the leaves wouldn't be
> *reflecting* green. :-)
>
In fact... leaves are not reflecting green... they are reflecting light which YOU
perceive
as green.
Not the same thing.
Take any satellite view in IR or UV, and you will see (in false colors) that all
plants
are not the same "green" (as well as providing information about water-need, it's also
changing from species to species: some smart agency detects drugs-fields that way).
As leaves in autumns show, they have various pigments to react with the light.
Chlorophyll (the whole family) works less with green. Hence the green of leaves.
But in the family, some are more efficient on different red/IR/blue/UV.
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Le_Forgeron wrote:
> In fact... leaves are not reflecting green... they are reflecting light
> which YOU perceive as green.
Well, true. Green, amongst others. :-)
> As leaves in autumns show, they have various pigments to react with the
> light.
Is that really where the colors come from? Other cholorphyll-related chemicals?
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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On 4/28/2009 10:02 AM, Kenneth wrote:
> Being a closet cosmologist at heart, the issue should keep me fascinated for weeks!
Dude, did you just come out of the closet on the POV-Ray newsgroups? :o
:)
--
...Chambers
www.pacificwebguy.com
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Chambers <ben### [at] pacificwebguycom> wrote:
> On 4/28/2009 10:02 AM, Kenneth wrote:
> > Being a closet cosmologist at heart, the issue should keep me fascinated for
weeks!
>
> Dude, did you just come out of the closet on the POV-Ray newsgroups? :o
>
> :)
Yes, it's true, I can finally admit it: I AM a wanna-be cosmologist!!
Ah, that felt good. Now I don't have to hide my true feelings from my friends
any longer.
KW
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From: Mike Raiford
Subject: Re: Very interesting color resolution examples
Date: 30 Apr 2009 13:07:32
Message: <49f9dad4@news.povray.org>
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Kenneth wrote:
> I wonder why WE can't see into the ultraviolet (and the infrared?) That
> SCIENTIFIC AMERICAN article points out that some existing creatures can see at
> least somewhat into the UV spectrum. So their retinas(?) must have developed
> some kind of protection that we don't (currently!) have. "Man is the superior
> being.": Bah, humbug.
Well, they can detect UVA, yes, which is mostly harmless. It's UVB that
causes burns and cancer.
And some people can see just barely into the IR band. I'm one that on
certain IR remotes, I can just barely see the die light up. It's
probably very long wave red that I'm actually seeing, though.
--
~Mike
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