"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...

Post a reply to this message

> 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.

Post a reply to this message

"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.

Post a reply to this 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...

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...

Post a reply to this message

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*

Post a reply to this message

"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

Post a reply to this message

> 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??

Post a reply to this message

> Just pondering that evolutionary adaptation is fascinating.

http://www.sciam.com/article.cfm?id=evolution-of-primate-color-vision

Might be of interest...

Post a reply to this message

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

Post a reply to this message

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

Post a reply to this message