HLG Normalized LUT Pack Manual

HLG Normalized LUT Pack

Preamble

The HLG Normalized LUT Pack has been developed to support quick and easy normalization of Hybrid Log Gamma (HLG) content across Monitors/Recorders and Editing/VFX applications that do not support the HLG Normalized Plugin. These can be used as Camera Input LUTs in programs such as DaVinci Resolve, Final Cut Pro and Adobe Premiere, or across Field Monitors/Recorders such as the Atomos Ninja/Shinobi/Shogun series. The HLG Normalized LUT Pack includes support for the HLG BT.2100 specification, the HLG BT.2408 recommendations as well as Sony’s custom HLG1, HLG2 and HLG3 implementations.

This LUT Pack complements the HLG Normalized Plugin which is geared for Applications that support the OpenFX standard and the HLG Normalized Transform which is targeted as an ACES IDT for DaVinci Resolve. The Premise for the HLG Normalized Transform and Plugin was the lack of proper support for transforming Scene referred HLG content in Video Editing (NLE) applications – especially in ACES workflows. To date, many of the existing HLG options continue to be inaccurate as they mainly target HLG in a Display referred context (i.e. HLG as an Output format) and not a Scene referred context (i.e. HLG as-shot on camera), hence the need for the HLG Normalized Transform and subsequently the Plugin. The LUT Pack extends this support to include External Recorders / Monitors and Video Editing / VFX applications.

To add further to the issue, there is quite a lot of confusion around exposing for Hybrid Log Gamma and Camera manufacturers don’t make the job any easier. Some cameras will correctly calculate the HLG (BT.2100) Exposure Values on the in-camera exposure meter. Others, such as the current range of Sony cameras, show completely wrong readings on the Exposure Meter. In the case of Sony, these calculations appear aligned to Rec.709 Scene instead of HLG BT.2100. In those situations, the Custom Zebra settings may need to be configured to the respective Middle Gray IRE parameters – assuming the Zebra settings can go below 22 IRE for the designated camera.

For future reference, the table on the right identifies the IRE values that each respective HLG implementation should be exposed to with reference to an 18% Middle Gray card. When using a Waveform Monitor, the Middle Gray chart/card readouts should align to these values before applying the HLG Normalized LUTs.

HLG TypeIRE Value
HLG BT.210021%
HLG BT.240838%
Sony HLG119%
Sony HLG220%
Sony HLG321%

The following table documents the Camera Native IRE values when over-exposing or under-exposing footage with Hybrid Log Gamma profiles aligned to BT.2100, relative to 18% Middle Gray at 21.2% IRE.

IRE %7.58.910.612.61517.821.225.23035.742.450.558.6
Stops-3-2.5-2-1.5-1-0.50+0.5+1+1.5+2+2.5+3
BT.2100 Exposure Chart

The following table documents the appropriate IRE values when over-exposing or under-exposing footage with Hybrid Log Gamma profiles aligned to BT.2408, relative to 18% Middle Gray at 38% IRE.

IRE %13.415.918.922.526.731.837.844.553.361.168.475.482.1
Stops-3-2.5-2-1.5-1-0.50+0.5+1+1.5+2+2.5+3
BT.2408 Exposure Chart

HLG Characteristic Curves

For reference, the diagram below plots the characteristic curves of HLG BT.2100, HLG BT.2408, Sony HLG1, HLG3 and HLG3 profiles against 10-bit coding values.

Installation

The LUTs should be copied to the designated LUT folder hierarchy of your desired Application or Monitoring System. This will vary from one application and Recorder/Monitor to another.

Windows

Depending on the target application, the LUTs may need to be copied to some of the following folders on Windows based systems:

  • C:\ProgramData\Blackmagic Design\DaVinci Resolve\Support\LUT\
  • C:\Program Files\Adobe\Common\LUTs\Creative
  • C:\Program Files\Adobe\Common\LUTs\Technical

MacOS

Depending on the target application, the LUTs may need to be copied to some of the following folders on Mac OS systems:

  • /Library/Application Support/Blackmagic Design/DaVinci Resolve/LUT
  • /Library/Application Support/Adobe/Common/LUTs/Creative
  • /Library/Application Support/Adobe/Common/LUTs/Technical

Linux

Depending on the target application, the LUTs may need to be copied to some of the following folders on Linux systems:

  • /home/resolve/LUT

Usage

This LUT pack consists of 80 LUTs spanning different HLG variations with various output Gammas and covers both Legal Video ranges and Data Levels in order to provide support across all Video Editing and Monitoring solutions.

The following HLG types are included:

  • HLG BT.2100
  • HLG BT.2408
  • Sony HLG1
  • Sony HLG2
  • Sony HLG3

Each HLG type includes four output variations with the following specifics:

  • A Technical Transform LUT with output to P3 D65 or Rec.709 Scene
  • A Technical Transform LUT with output to P3 D65 or Rec.709 Gamma 2.2
  • A Technical Transform LUT with output to P3 D65 or Rec.709 Gamma 2.4
  • A Technical Transform LUT with output to P3 D65 or Rec.709 Gamma 2.6
  • An Output LUT that converts to P3 D65 or Rec.709 with proper Tone and Gamut mapping

The first four Technical LUTs provide a base conversion, from which additional color grading and tweaking can be done. When the Tone Mapped Output LUT is selected, no further color grading or tweaking is required as this will map the color and dynamic range to cover the Rec.709 or P3 D65 Color Gamut and brightness level outputs.

All LUTs are included in either a Video Legal range for host applications such as Adobe Premiere and External Recorders/Monitors or covering the full Data range for program such as Final Cut Pro and DaVinci Resolve.

Final Cut Pro

To use the Camera LUTs in Final Cut Pro, it is necessary to perform a Color Space Override to “Rec.2020” and select the relevant HLG LUT as the designated Camera LUT. This will prevent FCP from applying the default HLG correction profile.