Excerpts from NAB 2008: Digital Cinema Summit
"Report from ASC: Look Management and its Relationship to Digital Cameras"
Excerpts from presentation by:
Lou Levinson, Senior Colorist, Post Logic Studios, ASC Digital Intermediate subcommittee
Liz Hinlein, 3cP consultant for DP Rodrigo Prieto (ASC,AMC) on "State of Play" (Universal 2009)
Josh Pines, Vice President of Imaging Research and Development, Technicolor Digital Intermediates
Glenn Kennel, Vice President, General Manager of Feature Films
About the ASC CDL
Text by Curtis Clark, ASC - Chairman of the ASC Technology Committee
ASC Technology Committee has addressed the language and mechanisms for reliably associating ASC CDL color corrections to images so that these CDLs can be accurately moved within the workflow from dailies through editorial to Digital Intermediate by linking the ASC CDL to the EDL (Edit Decision List) in ALE, FLEx, CMX EDL, or XML files .
- XML Input Description fields to include important data for camera mode settings, e.g., extended range log modes vs. rec.709
- XML Viewing Description carries information about the monitoring system and environment
- Provision is being made for a 10th ASC CDL parameter representing the saturation function
- Cross platform data exchange for RGB primary color grading/correction
Framework which allows the interchange of basic color correction functions between color correction systems made by different manufacturers. Lift / Gain / Gamma
Lift (dark tones), Gain (highlights), Gamma (mid-tones)
The terms Lift, Gain, and Gamma are commonly used by most color correction systems, but those definitions may vary in detail from system to system and manufacturer to manufacturer.
- Offset / Slope / Power
To avoid controversy, competition, and confusion, the ASC has proposed a set of three defined transfer functions with unique names.
- 9 important numbers
Offset (lift), Slope (gain), and Power (gamma) parameters for each ofthe red, green and blue color components; thus the three transfer functions for the three color components can collectively be described by nine parameters.
Demonstration of ASC CDL for ASC Membership
Hollywood, CA - On October 29th 2007, da Vinci Systems and Gamma & Density Co. took part in the first demonstration of the ASC CDL (Color Decision List) functionality for the ASC membership at the ASC Clubhouse in Hollywood. The ASC CDL has been developed by members and contributors of the ASC Technology Committee to provide an industry 'standard' for cross-platform exchange of primary RGB color correction data using Offset (lift), Slope (gain), and Power (gamma) functions.
The 3cP System was used for "on-set" color correction with the live color correction settings saved as ASC CDL XML files, which were transferred to a da Vinci Resolve system using a USB memory stick. The images were then available on the da Vinci system with the 3cP "on-set" color corrections intact, ready for final grading, providing full continuity of the DP's original vision.
Images from the two systems were compared so the audience could see there was no difference in color, contrast, saturation, or brightness between the 3cP on-set color correction images and images from the da Vinci Resolve system.
It was also demonstrated that the "on-set" color corrections were entirely reversible or modifiable after transfer to the da Vinci system. This is not the case when using 3D LUTs to transfer color corrections. Once a LUT is created, it can either be applied or not, but It cannot be further modified.
Example of ASC CDL Workflows with Gamma & Density's 3cP System
Panavision Genesis / 3cP System / ASC CDL - On-Set Workflow Click on image to zoom |
3cP System / ASC CDL / da Vinci - Post House Workflow Click on image to zoom |
Some other ASC CDL articles of interest :
- American Cinematographer: Color-Space Conundrum
- American Cinematographer: ASC Technology Committee Update
- Color Finesse 2 - Supports import and export of ASC CDL
- Cinematographer.com - The Daily Cinematography Resource