POV-Ray : Newsgroups : povray.general : Selective Palette for Output Server Time
8 Aug 2024 04:06:33 EDT (-0400)
  Selective Palette for Output (Message 1 to 3 of 3)  
From: Reuben Pearse
Subject: Selective Palette for Output
Date: 5 Apr 2001 08:45:23
Message: <3acc68e3$1@news.povray.org>
Hi all,

I was wondering if it is possible to get POVRay to generate an image using a
certain palette for colours (e.g. like the safe palette of 216 colours
sometimes used for GIF images).

Thanks,

Dooby
doo### [at] breathemailnet


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From: Christoph Hormann
Subject: Re: Selective Palette for Output
Date: 5 Apr 2001 08:51:50
Message: <3ACC6A67.D95AE3E3@gmx.de>
Reuben Pearse wrote:
> 
> Hi all,
> 
> I was wondering if it is possible to get POVRay to generate an image using a
> certain palette for colours (e.g. like the safe palette of 216 colours
> sometimes used for GIF images).
> 

Povray does not support generation of 8 or 4 bit indexed color image
files.  You have to use a seperate program to do conversion.  

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Scott Hill
Subject: Re: Selective Palette for Output
Date: 10 Apr 2001 11:15:47
Message: <3ad323a3@news.povray.org>
"Christoph Hormann" <chr### [at] gmxde> wrote in message
news:3ACC6A67.D95AE3E3@gmx.de...
>
>
> Reuben Pearse wrote:
> >
> > Hi all,
> >
> > I was wondering if it is possible to get POVRay to generate an image
using a
> > certain palette for colours (e.g. like the safe palette of 216 colours
> > sometimes used for GIF images).
> >
>
> Povray does not support generation of 8 or 4 bit indexed color image
> files.  You have to use a seperate program to do conversion.
>


    And you'll get much better results that way any how ! Basically, if you
have POV outputting 24bpp images then any decent image manipulation tool
will reduce that down to 8bit with very little loss of quality - how ? Error
diffusion, that's how - rather than just take a pixel, reduce it to 8bit and
then forget about it, error diffusion looks at how much error their is in
the 8-bit pixel compared to the 24-bit original and distributes this error
to neighbouring pixels - so the inaccuracies of the 24bit->8bit conversion
get smoothed out.

--
Scott Hill
Software Engineer.
NC Graphics (Cambridge) Ltd.
Web : http://www.ncgraphics.co.uk
E-mail : sco### [at] ncgraphicsnet
ICQ : 110661991


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