Christopher James Huff wrote:
> I've created a new image format for storing high dynamic range images. 
> The new format is quite simple to implement: it is basically a 16-bit 
> PNG with a gamma of 1, using half-precision floating point numbers 
> instead of 16 bit integers. It's a bit of a hack, but it seems to work 
> quite well.
> The floating point format I use is 5 exponent bits, giving an exponent 
> range from -16 to 15, and 11 mantissa bits, for a range of 0 to 2047. I 
> did not include a sign bit, thus the format can only contain positive 
> values...I do not think negative values are useful enough to warrant the 
> loss in precision. I might add a second 1-5-10 format if it turns out to 
> be useful.

This is an interesting idea although as long as there isn't support for 
such files at least in some applications it will not be so useful.  You 
might consider proposing this to the libpng guys so it might get added 
to libpng.

Signed values might be useful for non-Image applications but in most 
cases you would want at least 32bit floating point values for this.

Christoph

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