Photographic DCTLs

• Photographic DCTLs
  • Introduction
  • Installation and utils
    • The run.py script
    • Quick install for Windows users
    • DCTL compatibility
  • Verified DCTLs
    • Cineon color processing
      • Cineon exposure
      • Cineon inversion
      • ACES scene-linear and calibration curves
      • Cineon exposure
      • Cineon transform
    • ARRI LogC color processing
      • LogC exposure
      • LogC print
    • Utilities
      • Matrix
      • Stripify
      • Saturation
      • Tonecurve
      • Transform
  • Experimental DCTLs
    • LogC3 temperature
    • Grade
  • Reference charts
    • ACES Macbeth 50D 5203 EXR from rawtoaces
    • ARRI LogC3 stepchart - EXR 2K LogC3 encoding
    • ARRI LogC3 colorchecker - EXR 2K LogC3 encoding
  • References
  • Web Resources

Introduction

This set of DCTL scripts is all about experimenting with the math behind color science, including ARRI LogC, ACES AP0, Cineon, and more. It's a creative, photography-inspired take on color correction and grading, focusing on looks and print techniques instead of strict technical workflows. The project is still evolving, so new ideas and techniques will be added over time. Some of the concepts are a bit experimental and might overlap with Resolve's built-in tools, and the file names or structure could change as things develop.

Installation and utils

To use these tools into your DaVinci Resolve setup, begin by cloning the git repository or download the release package, which contains the DCTLs and headers.

Run python(.exe) run.py install in your terminal to copy the *.dctl and *.h files to the DaVinci Resolve LUT DCTL folder, ensuring they're accessible within your Resolve environment. The files can also be manually copied to /Library/Application Support/Blackmagic Design/DaVinci Resolve/LUT/DCTL on Mac and C:\ProgramData\Blackmagic Design\DaVinci Resolve\Support\LUT\DCTLon Windows.

For added convenience, the run.py script is provided, enabling easy access to various resources.

The run.py script

To open the DCTL readme documentation:

./run.py readme

For exploring DCTL examples:

./run.py examples

To access the DaVinci Resolve log file and initiate a trace:

./run.py install

To install *.dctl and *.h into DCTL directory:

./run.py log

To make a snapshot of hte DaVinvi Resolve DCTL folder:

./run.py snapshot

Quick install for Windows users

./install.bat

DCTL compatibility

All DCTLs are tested and confirmed to work with Metal, CUDA, and OpenCL on both Mac and Windows platforms.

Verified DCTLs

Cineon color processing

Cineon exposure

Cineon exposure from photographic stops, incorporating a zone based false color to aid in achieving correct exposure levels.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Cineon-Exposure.dctl

Cineon inversion

Cineon negative inversion with precise control over the dmin ratio based inversion process using adjustable parameters such as density, bit depth, offset, and density scale. You can specify dmin base values manually as floating-point numbers (obtained from tools like Pixel Analyzer in Nuke or similar software) or sample them using a rectangular sampler from the border or other dmin base areas.

ACES scene-linear and calibration curves

To account for the variations of film stock and the use of ECN-2 chemicals, developer time and temperature, camera and lightbox settings - calibration curves are applied to match ideal cineon code values. In this example, photoscanning was used along with the rawtoaces tool to convert the Camera RAW CR2 file to scene-linear ACES, starting with as much information as possible. However, because the science is not exact, manual tweaking using density scaling and calibration curves is needed depending on the setup.

Figure: Color calibration curves and macbeth charts at different exposures for adjustments.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Cineon-Invert.dctl
• https://github.com/AcademySoftwareFoundation/rawtoaces

Cineon exposure

Cineon exposure from photographic stops, incorporating a zone based false color to aid in achieving correct exposure levels.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Cineon-Exposure.dctl

Cineon transform

Cineon conversion to and from linear.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Cineon-Transform.dctl

ARRI LogC color processing

LogC exposure

LogC3 exposure from photographic stops, incorporating a zone based false color to aid in achieving correct exposure levels.

• https://github.com/mikaelsundell/dctl/blob/master/PD-LogC3-Exposure.dctl

LogC print

Made for print emulation, this DCTL applies DaVinci Resolve's built-in film looks to ARRI LogC3 and Cineon footage with adjustable controls for luminosity and color blending.

• https://github.com/mikaelsundell/dctl/blob/master/PD-LogC3-Print.dctl

Utilities

Matrix

Matrix adjustments, a utility for copying matrix values.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Stripify.dctl

Stripify

Matrix adjustments, this DCTL simplifies the color palette by pushing colors into a warm and cool strip.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Stripify.dctl

Saturation

HSV-based adjustments, this DCTL provides a tool for fine-tuning saturation using saturation in HSV.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Saturation.dctl

Tonecurve

Tone curve adjustments for contrast, shoulder and toe controls.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Tonecurve.dctl

Transform

Color space transformation to and from CIE XYZ linear.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Transform.dctl

Experimental DCTLs

LogC3 temperature

LogC3 CAT02 color temperature adjustments.

• https://github.com/mikaelsundell/dctl/blob/master/PD-LogC3-Temperature.dctl

Grade

Grade adjustments, this DCTL is experimental code for lift, gamma, gain and log controls.

• https://github.com/mikaelsundell/dctl/blob/master/PD-Grade.dctl

Reference charts

Reference charts for testing and verifying DCTLs. Additional formats are available in the Logctool project README:

• https://github.com/mikaelsundell/logctool

ACES Macbeth 50D 5203 EXR from rawtoaces

• Download: macbeth_50D_5203.exr

ARRI LogC3 stepchart - EXR 2K LogC3 encoding

• Download: logctool_LogC3_stepchart_DCI_2K.exr

ARRI LogC3 colorchecker - EXR 2K LogC3 encoding

• Download: logctool_LogC3_colorchecker_DCI_2K.exr

References

Github projects

• https://github.com/mikaelsundell/colortool
• https://github.com/mikaelsundell/logctool

Wikipedia

• https://en.wikipedia.org/wiki/Rec._709
• https://en.wikipedia.org/wiki/DCI-P3
• https://en.wikipedia.org/wiki/Grayscale

Format specifications

• http://www.dcimovies.com/archives/spec_v1_1/DCI_DCinema_System_Spec_v1_1.pdf
• https://docs.acescentral.com/specifications/acescc/#color-space
• https://www.arri.com/resource/blob/278790/dc29f7399c1dc9553d329e27f1409a89/2022-05-arri-logc4-specification-data.pdf
• https://dicomp.arri.de/digital/digital_systems/DIcompanion/index.html

DCTLs, apps and resources

• https://github.com/thatcherfreeman/utility-dctls
• https://github.com/AcademySoftwareFoundation/OpenRV/blob/main/src/plugins/rv-packages/additional_nodes
• https://skia.googlesource.com/skia/+/70e432e72745/gm/hsl.cpp
• https://colour.readthedocs.io
• https://github.com/ampas/aces-dev
• https://mononodes.com

Utilities

• https://www.desmos.com/calculator
• https://www.desmos.com/calculator/3zhzwbfrxd
• https://www.russellcottrell.com/photo/matrixCalculator.htm

Web Resources

• GitHub page: https://github.com/mikaelsundell/dctl
• Issues https://github.com/mikaelsundell/dctl/issues