I have a question about gamma settings when outputting to .png files.

Let's say I render an image in POV-Ray and output it to a .bmp image and
then use Paint Shop Pro to convert it to a .png image. When I use this image
as an image_map in POV-Ray it works as I expect it to do.

But when I render an image in POV-Ray and output directly to a .png image,
and then use that image as an image_map in POV-Ray then it doesn't work as I
expect it to. I can't figure out if it is because the image_map is not
gamma_corrected, or if it is because it *is* gamma_corrected, or if it is
because it is gamma_corrected twice, but anyway it is too dark.

Also, the .png image_maps made directly by POV-Ray have different
brightnesses relative to the scene when I use different Display_Gamma
settings in the scene with the image_maps. The .png image_maps converted by
Paint Shop Pro always have the same brightness.

What settings (both in the scene file and in the ini settings) should I use
to make POV-Ray output the same way as Paint Shop Pro does?

Is it a bug?

Greetings,

Rune S. Johansen

---
Updated October 7: http://rsj.mobilixnet.dk
Containing 3D images, stereograms, tutorials,
The POV Desktop Theme, 350+ raytracing jokes,
miscellaneous other things, and a lot of fun!

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I only know what you know.  I've seen the dark Png images too.  If a Jpg is
made out of one by saving from PSP it gets brighter, although the Png
actually looks the same IN Paint Shop Pro near as I can tell, but other
viewers can see them as much darkened from the original output which is seen
while rendering.
Willing to bet it's the 'assumed_gamma' thing where I usually use the 2.2
(darker) instead of 1.0 (lighter).

Bob

Rune S. Johansen <run### [at] inamecom> wrote in message
news:3809e733@news.povray.org...
> I have a question about gamma settings when outputting to .png files.
>
> Let's say I render an image in POV-Ray and output it to a .bmp image and
> then use Paint Shop Pro to convert it to a .png image. When I use this
image
> as an image_map in POV-Ray it works as I expect it to do.
>
> But when I render an image in POV-Ray and output directly to a .png image,
> and then use that image as an image_map in POV-Ray then it doesn't work as
I
> expect it to. I can't figure out if it is because the image_map is not
> gamma_corrected, or if it is because it *is* gamma_corrected, or if it is
> because it is gamma_corrected twice, but anyway it is too dark.
>
> Also, the .png image_maps made directly by POV-Ray have different
> brightnesses relative to the scene when I use different Display_Gamma
> settings in the scene with the image_maps. The .png image_maps converted
by
> Paint Shop Pro always have the same brightness.
>
> What settings (both in the scene file and in the ini settings) should I
use
> to make POV-Ray output the same way as Paint Shop Pro does?
>
> Is it a bug?
>
> Greetings,
>
> Rune S. Johansen
>
> ---
> Updated October 7: http://rsj.mobilixnet.dk
> Containing 3D images, stereograms, tutorials,
> The POV Desktop Theme, 350+ raytracing jokes,
> miscellaneous other things, and a lot of fun!
>
>
>

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