Re: ocio2icc - Can I Create An ICC Profile From An Existing 3dl/csp LUT?


Jeremy Selan <jeremy...@...>
 

On Fri, Sep 9, 2011 at 3:20 PM, Gresham Lochner
<gresham...@gmail.com> wrote:
 I believe I heard Jeremy mention Sony
brings their stuff in a neutral color space (in photoshop) rather than
trying to match what nuke see's with a cubic lut applied. Is that true?
Let me clarify. The colorspace we work in for texturing is partially
(but not totally) neutral.

Our rendering is in HDR linear, and the way our pixels get to the
scene is (approx):

(HDR scene-linear image) -> 1D Tonemapping to Display space (LDR
display pixels) -> 3D Filmic Color Warp (final film emulation preview)

In nuke/katana, as we're starting with hdr linear, both of these steps
(1d tone mapping + 3d color warp) happen in the viewer.

In photoshop, we paint directly in the LDR display pixel space, and we
apply only need to apply the 3D filmic component to preview the image
accurately.

It's nice to paint in this 'intermediate' colorspace because:
- the transformation back to scene-linear for rendering is only a 1d
transform (no inverse 3d luts)
- also, because the ldr painting space has a gamma very similar to the
monitor, things like color pickers / reference art work well.

For those who are not familiar with opencolorio.org, we've put
together a basic description of our color practices which is available
here. Of particular interest is the dt colorspace (diffuse-texture),
which corresponds to the intermediate space mentioned above.

http://opencolorio.org/workflow/spi_workflow.html
http://opencolorio.org/workflow/spi_vfx.html

-- Jeremy

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