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1 Nov 2024 09:21:30 EDT (-0400)
  [Doc] Photon TODO and Grey equation (Message 1 to 4 of 4)  
From: Le Forgeron
Subject: [Doc] Photon TODO and Grey equation
Date: 30 May 2002 09:43:00
Message: <3CF62C99.5080905@free.fr>
Version 3.5.beta.RC5.icl.win32


In 6.10.5.1, range_divider (photons/advanced technique)

There is a "TODO" ... is there any hope for it ?






In 6.5.4.2 Functions in Isosurface,

the equation for the .gray seems bogus, it is given as
   gray value = Red*58.9% + Green*11.4% + Blue*29.7%

which means that Red is brighter than Blue which is brigher than Green.
IMHO, for the human eyes, it should be
   gray value = Red*29.7% + Green*58.9% + Blue*11.4%
(Because Green is brighter than Red which is brighter than Blue)
Unless Pov is made for some insects or bees ?


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From: Apache
Subject: Re: [Doc] Photon TODO and Grey equation
Date: 30 May 2002 10:21:43
Message: <3cf63577$1@news.povray.org>
I'm not an expert in this, but if green is already brighter shouldn't that
be compensated by a lower factor (like .114) instead of making it even more
bright in comparison to the other two colors?

--
Apache
POV-Ray Cloth experiments: http://geitenkaas.dns2go.com/experiments/
Email: apa### [at] yahoocom
ICQ: 146690431


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From: Le Forgeron
Subject: Re: [Doc] Photon TODO and Grey equation
Date: 30 May 2002 10:46:51
Message: <3CF63B59.1080001@free.fr>
Apache wrote:

> I'm not an expert in this, but if green is already brighter shouldn't that
> be compensated by a lower factor (like .114) instead of making it even more
> bright in comparison to the other two colors?

Not for getting the gray level.
When using gray, the order of colour is :

Black,  Blue,    Red,   Magenta, Green, Cyan,   Yellow and White.
<0,0,0>,<0,0,1>,<1,0,0>,<1,0,1>,<0,1,0>,<0,1,1>,<1,1,0> and <1,1,1>

Yellow is very light gray.
Green is middle grey
Red is dark grey
and Blue is very dark grey.

Try using the formula and then sort the values. Check the order!


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From: Nathan Kopp
Subject: Re: [Doc] Photon TODO and Grey equation
Date: 30 May 2002 18:01:18
Message: <3cf6a12e$1@news.povray.org>
"Le Forgeron" <jgr### [at] freefr> wrote...
> Version 3.5.beta.RC5.icl.win32
>
>
> In 6.10.5.1, range_divider (photons/advanced technique)
>
> There is a "TODO" ... is there any hope for it ?
>

The range_divider is no longer needed, so this section of the documentation
has been dropped.

-Nathan


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