Post & the DI

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Hi K Wasley,

Let's take each question one at a time.

1) You are correct that a LUT is tied to a display.  So you if you create a LUT while looking at a monitor that is set to Rec709, then that LUT is tied to Rec709.  The key to creating a LUT that can be mapped to multiple displays/colorspaces is to create your look based on a larger color space and then map that larger space to smaller spaces.  Meaning if you start with a P3 to Rec709 LUT and build your specific look just before the P3 to Rec709 LUT, you can preview your LUT on a Rec709 monitor but you have a LUT that is tied to P3 once you remove the P3 to Rec709 component.  If you leave the P3 to rec709 component, that LUT is valid on a Rec709 display.  You are correct that the display colorspace is valid in both option 1 and option 2.

2)Fantastic that you referenced Steve Yedlin, I have worked with him and helped in some of his experiments.  He is extremely passionate about color and very technical in his process.  The Divinci process is a broad stroke methodology.  I present it as an option in that it may allow to create looks quickly with instantaneous  feedback.  If you want to take it to the next level, I encourage study.  That is how Steve learned.  Understand the differences between additive and subtractive color, understand film and how crosstalk works.  To create the indepth look you may want to achieve I recommend understanding the differences between classic film stocks not only in grey axis but individual color saturation when mapping from black to white.  To create the looks such as what Steve has been able to do,  data collection is key. 

3)  The LUT/s that I have worked with Roger in creating have had nothing to do with the Arri LUTs. They are are completely independent and built with his direct guidance.  In the general question of how to build a LUT.  In general I like to keep color and contrast independent.  Meaning that I would recommend first understanding the color pallet you want and then contrast.  Then double check that color still works once contrast has been established. 

4) Clipping and Clamping check is a technical check to make sure your LUT is smooth. "Natural" can mean different things so I'm really referring to the extreme brights and the extreme darks.

5) In my experience you can use the same LUT on both.  As long as they are both mapped to the same colorspace, in this case LogCV3 Alexa Wide Gamut.

6) Currently Dci-P3 is the standard colorspace for Digital Cinema.  XYZ is the colorspace that DCP's (DCDM's) are mapped to.  XYZ is an extremely large colorspace that was created with future proofing in mind.  In essence, Digital Cinema Projectors are P3 projectors.  So when Digital Cinema is mapped to XYZ it's in essence P3 inside XYZ.  The reason for this is that as Digital Projection improves and their colorspace capabilities improve, XYZ as the colorspace container for Digital Cinema will still be valid but larger colorspaces will be able to be mapped into them.  Those future projectors will allow for current P3 projection to occur based on a calibration setting so we should always be able to see "intent".  I would take a look at Rec2020.  That's the up and coming colorspace and when people talk about HDR, this will be the medium that will employ that colorspace first.

7)Can you reference for me the ICC Profile issue?  You can work with ICC Profiles.  It's just a bit of a different system and to be honest, once Photoshop started accepting LUT's I haven't done a ton with with them.  Usually ICC Profiles are used as a means of calibrating monitors, as the example you gave.  Sometimes the hard part in utilizing them is that they can be integrated into an operating system and it's difficult to be certain of the order of operations that are occurring.  Also, I try to avoid computers making assumptions for me when ever possible because I'm a bit of a control freak in that respect.

I hope that helps,

Please let me know if I missed the mark in any of my responses.


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