POV-Ray : Newsgroups : povray.newusers : Emulate browser rendering of png Server Time
25 Nov 2024 03:30:59 EST (-0500)
  Emulate browser rendering of png (Message 1 to 4 of 4)  
From: jaysonfire
Subject: Emulate browser rendering of png
Date: 9 Oct 2006 15:55:00
Message: <web.452aa8a53de5448e8c9f8c6a0@news.povray.org>
I'm new to povray, and I'm trying to do what I hope is a fairly basic scene.

I'm trying to get povray to help me produce GIF files from the combination
of a PNG and a background color.  The idea is to generate printable
versions of png images I'm displaying on a website.

I've set up povray with the background color, the png viewed from above, and
the ambient light source, and I'm converting the resulting TGA file into
GIF.
And it works, but it's coming out a bit darker than the image as rendered in
my browser, and I'm not sure what to do to get the povray version to look
the same.

Any suggestions would be greatly appreciated.
Thanks,
Jay


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From: Marc
Subject: Re: Emulate browser rendering of png
Date: 9 Oct 2006 16:45:29
Message: <452ab4e9@news.povray.org>

web.452aa8a53de5448e8c9f8c6a0@news.povray.org...
> I'm new to povray, and I'm trying to do what I hope is a fairly basic
scene.
>
> I'm trying to get povray to help me produce GIF files from the combination
> of a PNG and a background color.  The idea is to generate printable
> versions of png images I'm displaying on a website.
>
> I've set up povray with the background color, the png viewed from above,
and
> the ambient light source, and I'm converting the resulting TGA file into
> GIF.
> And it works, but it's coming out a bit darker than the image as rendered
in
> my browser, and I'm not sure what to do to get the povray version to look
> the same.
>
> Any suggestions would be greatly appreciated.
> Thanks,
> Jay
>
>
Let ambient light as default, put finish{ambient 1 diffuse 0}to your png
That should do it

Marc


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From: Tim Nikias
Subject: Re: Emulate browser rendering of png
Date: 9 Oct 2006 16:47:43
Message: <452ab56f$1@news.povray.org>
jaysonfire wrote:
> I'm new to povray, and I'm trying to do what I hope is a fairly basic scene.
> 
> I'm trying to get povray to help me produce GIF files from the combination
> of a PNG and a background color.  The idea is to generate printable
> versions of png images I'm displaying on a website.
> 
> I've set up povray with the background color, the png viewed from above, and
> the ambient light source, and I'm converting the resulting TGA file into
> GIF.
> And it works, but it's coming out a bit darker than the image as rendered in
> my browser, and I'm not sure what to do to get the povray version to look
> the same.
> 
> Any suggestions would be greatly appreciated.
> Thanks,
> Jay

Are you using an assumed_gamma in your global_settings block? AFAIK, the 
default display_gamma set for POV-Ray is 2.2, if you don't use 
assumed_gamma, the images, if used with ambient 1 diffuse 0 and no 
lightsource, will look a little different. In any case, assumed_gamma is 
probably the cause and looking into it might solve your problem, for me, 
using assumed_gamma set at 2.2 often solved that kind of problem when 
using POV-Ray as a compositing tool instead of a renderer. :-)

Regards,
Tim


-- 
aka "Tim Nikias"
Homepage: <http://www.nolights.de>


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From: jaysonfire
Subject: Re: Emulate browser rendering of png
Date: 10 Oct 2006 15:25:00
Message: <web.452bf2f3e15d36ff8c9f8c6a0@news.povray.org>
Thanks to both of you!

I was already using: ambient 1 diffuse 0
so it was good to know that I was on the right track there.

But I was not setting the assumed_gamma, and that made a big difference.
Playing with it a little, I found that assumed_gamma 2.4 got me about as
close as I can get.


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