> I'd rather let the experts explain what this is all about because it's quite
> fuzzy for me too !
> Basically the trick is to get a HDR file and use it on a big sphere in a
> radiosity scene. This I figured out.
> What HDR shop does is 1) let you view and edit HDR files and 2) create HDR
> files out of sequences of normal images (particularly ones from digital
> cameras).
> Actually this part is *** very *** confusing to me right now. Anyone knows
> if it possible to take a single regular image and turn it into a HDR version
> ? I've tried it and get a HDR file but I'm not sure it really works (or make
> sense at all ?)...
>

First HDR has nothing to do with the kind of mapping you use. If you look at
Paul Debevec' page you'll find also box-mapped HDR images or simple planar
ones. High Dynamic Range Images means that the full color indensity (or better
the lumens) is also stored into the image file. This is a much better representation
of "reality" as Low Dynamic Range as represented by using the (poor) RGB
color space (used within jpg or png files). POV does internal work with high
dynamic range and I guess most of you have already used a light source that is
"brighter" than rgb <1,1,1>. I usually do so and this is the way Jaime's lighting
system does work. This is also "HDR".
Imaging a white sheet of paper, white clauds on a sunny day, the sun itself or
a exploding super nova. In rgb color space, all of them are represented as
simple rgb <1,1,1>. And as POV does already calculate with HDR values
it seems really logic and useful to me not to be restricted when it comes to
input AND output if image formats. This would give you simply the similar
possibilities that are normal to any photographer.
Oh, and one more thing: HDR means simply that the full range of gamut and
lumens is coverd by the image format. The files from Paul Debevec' page are
in the Radiance-format as developed by Greg Ward, who did also design the
LogLUV format  (also HDR). There are others around as e.g. TIFF-Pixar-Log
as used by (you guessed it) Pixar.

-Ive


P.S. sorry Gilles it did happen again, wrong button in Outlook.

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