Thanks Lewis, I was moving in the same direction - but you served me a lovely dish :)
There is still miniscule differences in the darkest of the darks - but these are not noticable if not gaining up by a zillion. Thanks a bunch!! /fredd On Tue, Jan 31, 2012 at 11:58 AM, Lewis Saunders <[email protected]>wrote: > Fredrik Pihl wrote: > > I run all and view in linear. > > And I cannot replicate the grade exactly.... > > 3D LUTs don't tend to work very well on linear images, as you're > discovering :) Because the values for the shadows are all squashed > into about 0.0...0.1 it's hard to get enough points in that area, even > with massive 64x64x64 cubes. > > I'd try converting to Cineon for the 3D LUTing part. The Vectorfield > node has input and output colorspace options for exactly this reason. > > Under your CMSTestPattern try a Colorspace set to Cineon in, linear > out. Then your grade nodes. Then another Colorspace set to linear > in, Cineon out, then GenerateLUT. Once you've made the LUT you can > use it on linear data with a Vectorfield node as long as you set its > two Colorspace dropdowns to Cineon. > > This also allows you to use 3D LUTs for the full Cineon range, so > you're not limited to linear values from 0..1. You can use something > like -0.1 to 12.0. > > I admit that I still see slight differences between different > applications using the same 3D LUT sometimes. I think this is due to > different interpolation methods. I've never managed to get Houdini, > Flame and Nuke to agree 100% on what the same LUT should look like, > but with 32x32x32 cubes it's not enough of a difference to be a > problem. > > -- > Lewis Saunders > trilinear fields for life > London > _______________________________________________ > Nuke-users mailing list > [email protected], http://forums.thefoundry.co.uk/ > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users > -- __________________________________________________ *Fredrik Pihl - **visual effects supervisor - digital compositor* *UNITED IMAGE CREATORS AB* rönnvägen 11, se-14144 huddinge, sweden +46-708-559 559
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