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developing a theatre lut for grading

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Chris Wright
developing a theatre lut for grading
on Sep 30, 2017 at 2:01:33 am

hi everyone,

I am creating a dead 100% accurate lut for theatre projectors. There's so much wrong info out that
that I had to go back to the original SMPTE-RP-431. Even though XYZ supports many types of gamma, I needed something that is exactly the same. I eventually had to research how the projectors themselves are calibrated to understand why people have so many problems grading for theatre.

I know some people tried after effect's dcdm xyz 5900k color profile but it has problems and others tried resolve's rec. 709 to XYZ lut.

As it turns out, DCDCM X’Y’Z theatre projectors are calibrated using white point trfg D63 (6300K) gamma 2.6 using xenon bulbs’ native color temp to pass the greyscale test using a reference white level at 48 cd/m2 or 14.00 fl.(SMPTE-RP-431)

A lot of DCP programs do the XYZ conversion but they use D65 or D60 white points which doesn't match
D63 or they have gamma conversion not 2.6.

I was actually amazed that wikipedia got the color primaries correct. they exactly match RP-431!
https://en.wikipedia.org/wiki/DCI-P3

does anyone have a XYZ colorspace projector or a way to test my research in projector calibration?
once completed, we will have a lut that is 100% perfect for theatre as a pure profile calibration.


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Chris Wright
Re: developing a theatre lut for grading
on Sep 30, 2017 at 2:35:07 am
Last Edited By Chris Wright on Sep 30, 2017 at 4:29:23 am

here is the dci spec rec709 to XYZ D63 lut

https://f1.creativecow.net/11730/rec-709-to-dci-xyz-d63-spec?uploaded=file


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