>  Of course funny things may happen if there are two PNGs in the wegpage
> with *different* gamma info. (IOW, what should be done to the other
> elements in the page?)

The gamma chunk within PNG's  just describes how the image data within
the PNG has to be interpreted and does of course not tell the browser how
to display the other elements of the page.
You can use multiple PNG files with different gamma settings on the same
web page without problems. Firefox (and meanwhile even IE) do work just
fine with this.

>> This certainly is no PNG standardization group's fault, some programs
>> just act wrong.
>
>  Right, but think about image formats which do not support any gamma info.
> No gamma-related problems appear there.

Wrong. The image data within all common 8 bit per sample graphic formats
(tga, bmp, pnm, tiff, jpeg and so on...)  is usually gamma corrected in some
way. (As someone else already mentioned here: the human eye is more
sensitive in the "darker" color range.  To avoid color banding, images
- at least 8bps ones - indeed should use a non linear color response curve).
So, as long the gamma value is not written to the file,  we have always just
a guessing game about the way the image data has to be "seen".
Remember remarks like: "..but the colors look a little bit washed out on
my monitor" or " ...the image appears to dark here...".

There is a good reason why programs like Photoshop include not just
the gamma info but a complete icc profile within image files like jpeg,
tiff and png. Sadly enough that color profiles are almost never used by
other applications (including POV-Ray).

Final note: I think there is no "gamma problem" at all - just the usual
problem that people do not really know what they are doing.

Final final note: back in 1992 (IIRC) I was working with some SGI
graphic workstations. There was no need to even think about
gamma correction because the operating system (together with
graphics card and monitor) did all the gamma stuff properly by
itself.
Sometimes I'm really wondering about the technical progress within
the IT industry.

-Ive

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