POV-Ray: Newsgroups: povray.beta-test: [Doc] gray equation

POV-Ray : Newsgroups : povray.beta-test : [Doc] gray equation		Server Time 29 Jul 2024 10:21:33 EDT (-0400)

From: Le Forgeron
Subject: [Doc] gray equation
Date: 11 Jun 2002 04:25:12
Message: <3D05B3FD.5000607@free.fr>

Version 3.5.beta.RC6.icl.win32
(was already signaled for RC5)

In 6.5.4.2 Functions in Isosurface,

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

which means that Red would be brighter than Blue which would be 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)

Or at least something in the line like : 60% Green, 30% Red, 10%Blue
and not 60% Red, 30% Blue, 10% Green


-- 
Non Sine Numine
http://grimbert.cjb.net/
Puis, s'il advient d'un peu triompher, par hasard,

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From: Scott Moore
Subject: Re: [Doc] gray equation
Date: 11 Jun 2002 06:28:39
Message: <p2kbgugbfiq699qlvg1cr5bsumir90n0mg@4ax.com>

On Tue, 11 Jun 2002 10:25:33 +0200, Le Forgeron <jgr### [at] freefr>
wrote:

>Version 3.5.beta.RC6.icl.win32
>(was already signaled for RC5)
>
>In 6.5.4.2 Functions in Isosurface,
>
>the equation for the .gray is bogus, it is given as
>   gray value = Red*58.9% + Green*11.4% + Blue*29.7%
>
>which means that Red would be brighter than Blue which would be 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)
>
>Or at least something in the line like : 60% Green, 30% Red, 10%Blue
>and not 60% Red, 30% Blue, 10% Green

I agree - gray should say Red*29.7% + Green*58.9% + Blue*11.4%

Scott

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From: ingo
Subject: Re: [Doc] gray equation
Date: 11 Jun 2002 06:44:26
Message: <Xns922A822755B70seed7@povray.org>

in news:3D0### [at] freefr Le Forgeron wrote:

> the equation for the .gray is bogus, it is given as
>    gray value = Red*58.9% + Green*11.4% + Blue*29.7%
 
> for the human eyes, it should be
>    gray value = Red*29.7% + Green*58.9% + Blue*11.4%
> 

What does the source say?

Ingo

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From: Thorsten Froehlich
Subject: Re: [Doc] gray equation
Date: 11 Jun 2002 07:15:21
Message: <3d05dbc9$1@news.povray.org>

In article <Xns### [at] povrayorg> , ingo <ing### [at] homenl>  
wrote:

> What does the source say?

The correct(ed) thing :-)

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

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