TransWikia.com

Correct gamma for SMPTE ST-2084 EOTF

Video Production Asked on November 14, 2021

I recently purchased an Apple Pro XDR display that has an HDR reference mode specified as follows:

HDR Video (P3-ST 2084)
Use this mode for 4K or ultra high-definition
video production workflows up to 1000 nits (full-screen sustained)
using the wide color P3 primaries and the high-dynamic-range SMPTE
ST-2084 EOTF. This mode is designed for controlled viewing
environments set up per ITU-R BT.2100.

When exporting raw files using the Canon Cinema RAW Development tool to ProRes 4444 for post production in Premiere I can choose the colour space and gamma.

Am I correct to assume that DCI-P3 is the right color space to choose?

And what gamma should I select? The only choices I have with this color space are

  • Canon Log 2
  • Canon Log 3
  • DCI

Should I ideally be using a different gamma for the ST-2084 standard or does it not matter?

enter image description here
enter image description here

One Answer

The short answer is: You don't pick a color space for your RAW material based on what kind of monitor you're using.

A color pipeline is a very complicated series of mathematical conversions, which is heavily dependent upon:

  1. The operating system's color management settings, such as .icc device profiles from manufacturers, and/or calibration software.
  2. The file recorded by your camera; what settings were used to write the file, the lighting conditions on set, the monitoring conditions on set, whether any in-camera "looks" were used when the file was created, whether those looks should be present in the final image, etc.
  3. Your NLE's color management and monitoring settings
  4. Your viewing environment. The light levels and color temperature of a color grading suite are standardized by SMTPE, as well as the color of surrounding walls and furniture.
  5. The destination format, monitoring conditions, and viewing environment. Where do you plan to show your work? YouTube? Then rec.709 is probably a safe choice for destination format, but you could still use a larger working color space. But if you're delivering a feature film to DCI-P3, upstream rec.709 would be a bottleneck. The same goes for HDR, which is an entirely different beast.

So, without more information about these factors, and what you're trying to accomplish, there's no right or wrong answer at this stage. The choice you're presented with is essentially: Which working color space do you want to use for the interpretation of your camera RAW file? As long as this space is larger than what you intend to deliver, then you could use any of them. If you're delivering to the internet, using the most common space, then they're all large enough. OTOH, if you will be the only person watching the output and you want it to look the best it can look on your new monitor, then use a space that's as large as your monitor is capable of reproducing, or larger.

Gamma is a different, but similar question. You don't use a gamma "large enough" to contain a certain set of values like you do with color space. But the "correct" gamma to chose is dependent upon the gamma your monitor is currently displaying, and the gamma of your destination material. Ideally, you'd set your monitor to be the same gamma and color space as your intended target. Here, let me stress, I'm talking about your MONITORING gamma matching your destination format. But your working gamma (the menu item you're asking about) could still be any gamma, or it could be log encoded, or even linear (especially for VFX compositing).

Answered by Jason Conrad on November 14, 2021

Add your own answers!

Ask a Question

Get help from others!

© 2024 TransWikia.com. All rights reserved. Sites we Love: PCI Database, UKBizDB, Menu Kuliner, Sharing RPP