16-bit Open EXR

[Thomas Singh]

I'm curious if 16-bit Open EXR is a part of your workflow?

[Dylan R. Hopkin]

Yes, VFX comps often get delivered as EXR for feature films and TV drama.

[Thomas Singh]

Do you handle them differently than cineon DPX files? Is there anything I should know about or prepare before receiving them? Waiting a batch next week. 

[Margus Voll]

Sometimes compression helps on file size but i think there was post if that affects playback.
Can not remember now the place it was talked about but felt like it could depend on system.

I use them daily basis for VFX shots coming back specially ACES in mind as all prores and such killed color data in heart beat.
My system does not seem any different but really depends on your machine, drives and overall performance vs resolution.

Better is to test it out every time when you can before job how your machine and platform handles it.

Also keep in mind and talk to your VFX house if any involved how they give you mattes and in which channel as EXR can have many many embeded. Works great if everybody knows what they are doing.

[Andy Minuth]

One should make sure to save Linear data to OpenEXR files, to maintain the best color fidelity. A log colour space saved to an OpenEXR file might work, but will only use a small fraction of the available bit depth. 

[Thomas Singh]

Strange that a 'linear format' got that popular. Guess it means you need to de-linearize it as most color approaches today starts with log. Do you happen to know why EXR is linear and not log @Andy Minuth? Not proper terms I know.

Edited February 25, 2018 by Thomas Singh

[Andy Minuth]

Log encodings were developed to effectively store high dynamic range images with integer codings. Integer formats are limited in dynamic range to 0..1.

OpenEXR is a much more advanced idea and was developed for the computer-graphics industry, where linear floating-point coding is a native format. It combines a lot of advantages: For example the effective coding of log, with the almost unlimited dynamic range of floating-point, etc.

[Thomas Singh]

Interesting thought that linear images can hold more information than log. 

[Dennis Schmitz]

Started using a linear workflow using ACES for my first feature film (am a producer, was DP and do Colorgrading and some VFX) a few weeks ago.

Premiere for Editing -> AAF for Audio -> XML to Resolve -> Grading in ACES CC still using REC709 ODT -> linear OpenEXR DWAA for FX without ODT -> OCIO linear workflow in After Effects -> OpenEXR DWAA back to Resolve -> ACES with ODT again.

Everything looks like it should, extended DR AND HDR compability in the future.

[Cary Knoop]

On 2/18/2018 at 9:44 AM, Andy Minuth said:

One should make sure to save Linear data to OpenEXR files, to maintain the best color fidelity. A log colour space saved to an OpenEXR file might work, but will only use a small fraction of the available bit depth. 

Because you need less bit depth in log with the same fidelity.  Most of the bit depth is wasted in the highlights in linear while you need a lot of it in the shadows.