We don't really care about the color correction effect in the Image Clip Fx for HDR. It's a classic correction effect that converts RGB pixels to HSV and back, which necessarily means clipping HDR values. If you want to work with HDR images, you have to use nodes in the render tree such as multiply. The render tree is the place to work in floating point. Hue and saturation do not necessarily make sense with HDR images. Luminance is also a clamped color space concept, in fact here or in photoshop and other products, it's an operation slanted for NTSC luminance. All three Hue, saturation, and luminance are all concepts that exist for user interface in a low dynamic range world.
> -----Original Message-----
> From: Tim Leydecker
>
> O.k. Thomas,
>
> I missed that bit in Luc-EricÂs previous post:
>
> >>If you're using HDR, you can't enable the Image Clip effects
>
> I didnÂt realize Colorcorrection as implemented in an
> Image>Adjust section is 8(16)bit only. Makes sense,
> as the FXtree is *only* 16bit as well.
>
> I had asumed that the input, regardless of itÂs bitdepth,
> would be normalized to the 0-1 range only for the
> sliders, e.g. 0.1 would be a compareable lumavalue
> in any 8,16,32bit b/w gradient but obviously the higher
> the bitdepth, the more steps available for rendering and
> the smoother the output.
>
> Thanks for making me aware of the clipping to 8/16bit.
>
> IÂll log a featurerequest to have this changed, e.g. have
> CC-Operations work without prior clipping in a later
> version of XSI. I guess they are looking into this allready, tho.
>
> Cheers
>
> tim
>
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