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On 28/02/2015 15:56, James Holsenback wrote:
> then i should have replied to the OP inquiry about blue dress instead
Forgiven. ;-)
--
Regards
Stephen
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Am 28.02.2015 um 15:54 schrieb MichaelJF:
> But this would only explain one part of the black-blue vs. White-Gold riddle.
I think the enigma is easily explained as a combination of multiple effects.
First, the facts:
(1) One very obvious technical flaw of the image is that the background
is hopelessly overexposed.
(2) The image has another (related?) technical flaw, in that there is a
yellowish overlay across the entire image; this might be due to
overexposure, stray light from a poor or dirty lens, an uncalibrated
camera, some automatic whitepoint adjustment gone rogue, or a
combination thereof. At any rate, it results in a significant shift in
brightnss and colour contrast, and also some shift in hue, of the dress;
thus, instead of pitch black and royal blue we all physically see a kind
of brownish grey and pastel blue.
(3) Most viewers' displays and/or viewing environments are probably not
calibrated, adding a multitude of other brightness, contrast and colour
distortions, which differ between viewers.
Now, it all boils down to how individual people's brains make sense of
the image, which is a result of the above different visual input
combined with different viewer expectations. There are essentially three
options:
(A) The brain correctly identifies the flaws of the original image,
auto-correcting the colours of the dress back to the original royal blue
& black.
(B) The brain takes the overexposured background as an indication that
the image was taken against the light source, expecting the dress to be
underexposed, and thus performing some auto-"correction" that in fact
just enhances the effect to the point where the dress is seen as white &
gold.
(C) The brain takes the colours of the dress at face value (to some
degree, that is), seeing neither the original royal blue & deep black
nor the reported white & gold, but a pastel blue & slightly brownish
dark grey. (This is actually what my brain seems to be doing, at least
when viewing the image on my super-duper calibrated display.)
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On Sat, 28 Feb 2015 17:56:48 +0200, James Holsenback <nom### [at] nonecom>
wrote:
> On 02/28/2015 10:35 AM, Stephen wrote:
>> On 28/02/2015 14:56, James Holsenback wrote:
>>> On 02/28/2015 07:38 AM, Stephen wrote:
>>>> On 28/02/2015 12:01, Thomas de Groot wrote:
>>>>> On 28-2-2015 12:56, Le_Forgeron wrote:
>>>>>>> -Nekar Xenos-
>>>>>>>
>>>>>>>
>>>>>> It's only a variation of the checker board in the shadow of a
>>>>>> cylinder.
>>>>>>
>>>>>
>>>>> ???
>>>>>
>>>> +1
>>>>
>>>>
>>> http://www.nytimes.com/interactive/2015/02/28/science/white-or-blue-
dress.html?_r=0
>>>
>>>
>>
>>
>> Thanks Jim but I think that the ??? was for "the checker board in the
>> shadow of a cylinder"
>>
>> When I looked at the image I see gold and white with a tinge of blue.
>> And when I sampled the image on the BBC site the Gold was about
>> <125,109,73> and the other <130,136,187>, roughly.
>>
>
> then i should have replied to the OP inquiry about blue dress instead
I posted on chrome with my phone but now my OP doesn't show up on Opera
Mail on my PC. Strange.
--
-Nekar Xenos-
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On Sat, 28 Feb 2015 13:56:37 +0200, Le_Forgeron <jgr### [at] freefr> wrot
e:
>> -Nekar Xenos-
>>
>>
SInce I can'te reply to myself, I'll post this here. It seems there was
something that gave off a lot of yellow tint radiosity. Maybe there was
a
taxi behind the photographer. here's a quick scene that basically
demonstrates the principle:
// Persistence of Vision Ray Tracer Scene Description File
// based on Radiosity scene.pov
// Radiosity sample for POV-Ray version 3.7
//
// Based on a scene by Friedrich A. Lohmueller, Dec 2010
// Derived from a sample of Bob Hughes,2001
//----------------------------------------------------------------------
----
#version 3.7;
#default{ finish{ ambient 0.1 diffuse 0.9 }}
//----------------------------------------------------------------------
----
#default{ finish{ ambient 0 diffuse 1 }}
//------------------------------------------
#include "shapes.inc"
#include "colors.inc"
#include "textures.inc"
//------------------------------------------
global_settings{
ambient_light 1
radiosity {
// pretrace_start 1
// pretrace_end 1
error_bound 0.6
count 50
// brightness 1
// gray_threshold 0
// media on
// normal on
recursion_limit 2
} // --------------
}// end global_settings
// ----------------------------------------
camera{ location <0, 14, -20>
right x*image_width/image_height
rotate 12*y
look_at <-1.25,2.8,0>
angle 33
}
sky_sphere{ pigment { color rgb <1,1,.1>*100} }
// fog
---------------------------------------------------------------------
// ground
------------------------------------------------------------------
plane{ <0,1,0>, 0
pigment{ color rgb 1}
} // end of plane
// -----------------------------------------
//box{-50,50 hollow pigment{colour rgb <1,1,0>}finish{diffuse 1}}
union {
#for (Cnt,1,3)
difference {
box {<-1,-1,-1>,<1,1,1> }
sphere {0,1.40 inverse }
sphere {0,1.25}
texture{ pigment{ color rgb ((Cnt/2)=(int(Cnt/2)))*<.1,.1,.7>+.0
3}//
Blue/Black
finish{ phong 1 diffuse 1-Cnt/10 }
}
translate<0,0,0>
scale 1+Cnt*0.65
translate <0,1+Cnt*0.30,0>
rotate Cnt*<0,-22,0>
}//----------
#end
scale <1,1,1>
translate<0,1,0>
}
// -----------------------------------------
--
-Nekar Xenos-
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From: Doctor John
Subject: Re: Can Pov-Ray illustrate the blue dress principle
Date: 28 Feb 2015 14:00:16
Message: <54f21040$1@news.povray.org>
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On 28/02/15 18:36, clipka wrote:
<snip>
>
> (C) The brain takes the colours of the dress at face value (to some
> degree, that is), seeing neither the original royal blue & deep black
> nor the reported white & gold, but a pastel blue & slightly brownish
> dark grey. (This is actually what my brain seems to be doing, at least
> when viewing the image on my super-duper calibrated display.)
>
I hate to say this, but: Me too.
John
--
Protect the Earth
It was not given to you by your parents
You hold it in trust for your children
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Am 28.02.2015 um 19:37 schrieb Nekar Xenos:
> I posted on chrome with my phone but now my OP doesn't show up on Opera
> Mail on my PC. Strange.
Maybe because your message comes without any body text, just a signature
line?
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From: Thomas de Groot
Subject: Re: Can Pov-Ray illustrate the blue dress principle
Date: 1 Mar 2015 03:14:40
Message: <54f2ca70$1@news.povray.org>
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On 28-2-2015 16:35, Stephen wrote:
> On 28/02/2015 14:56, James Holsenback wrote:
>> On 02/28/2015 07:38 AM, Stephen wrote:
>>> On 28/02/2015 12:01, Thomas de Groot wrote:
>>>> On 28-2-2015 12:56, Le_Forgeron wrote:
>>>>> Le 28/02/2015 08:48, Nekar Xenos a écrit :
>>>>>> -Nekar Xenos-
>>>>>>
>>>>>>
>>>>> It's only a variation of the checker board in the shadow of a
>>>>> cylinder.
>>>>>
>>>>
>>>> ???
>>>>
>>> +1
>>>
>>>
>> http://www.nytimes.com/interactive/2015/02/28/science/white-or-blue-dress.html?_r=0
>>
>>
>
>
> Thanks Jim but I think that the ??? was for "the checker board in the
> shadow of a cylinder"
It was for the /blue dress/ initially, /and/ for the answer which did
not make sense to me in that context. I am satisfied now :-)
--
Thomas
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From: FractRacer
Subject: Re: Can Pov-Ray illustrate the blue dress principle
Date: 1 Mar 2015 03:59:30
Message: <54f2d4f2$1@news.povray.org>
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> On Sat, 28 Feb 2015 13:56:37 +0200, Le_Forgeron <jgr### [at] freefr> wrote:
>
>>> -Nekar Xenos-
>>>
>>>
>
> SInce I can'te reply to myself, I'll post this here. It seems there was
> something that gave off a lot of yellow tint radiosity. Maybe there was
> a taxi behind the photographer. here's a quick scene that basically
> demonstrates the principle:
>
>
> texture{ pigment{ color rgb
> ((Cnt/2)=(int(Cnt/2)))*<.1,.1,.7>+.03}// Blue/Black
> finish{ phong 1 diffuse 1-Cnt/10 }
> }
Maybe use srgb instead rgb...
--
Lionel
Do not judge my words, judge my actions.
---
http://www.avast.com
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