Academy Color Encoding System
In 2004 more than 50 of the motion picture industry's leading technologists and practitioners came together under the auspices of the Science and Technology Council to begin work on an architecture and supporting tools for digital motion picture production, mastering and archiving. The result, the Academy Color Encoding System (ACES) is currently undergoing industry-wide production trials by the major Hollywood studios, widespread adoption by equipment manufacturers and post-production/VFX facilities, and standardization by the Society of Motion Picture and Television Engineers.
ACES provides benefits throughout the motion picture production chain:
- Eliminates uncertainty between on-set look management and downstream color correction
- Preserves the full range of highlights, shadows and colors captured on-set for use throughout the post-production and mastering processes
- Preserves the ability to "light by eye" rather than relying on video monitors
- Enables future expansion of the creative palette by removing the limitations of today’s legacy workflows
For Visual Effects and Post-production Facilities:
- Enables reliable, unambiguous interchange of images from all film and digital sources
- Enables flexible workflow design
- Preserves the use of "custom looks"
- Simplifies visual matching of different cameras
- Provides colorists with a better starting point and is designed to deliver the full dynamic range of progressive generations of digital motion picture cameras
For Content Owners:
- Offers simpler remastering for non-theatrical distribution platforms
- Uses a standardized archival file format
- Preserves the highest quality images for use with next-generation display technologies
When ACES development began in 2004, the motion picture industry lacked clear standards for the interchange of digitally mastered motion picture elements. The DPX file format (SMPTE 268M, originally developed in 1993) was widely used, but it left many technical details up to the end-user, which led to many different interpretations and implementations as well as a proliferation of proprietary and non-standard image file formats. The result has been increased inefficiency, increased costs and reduced image quality.
Today's motion pictures are collaborative efforts, generally involving many different facilities for visual effects, post-production and mastering. The challenges faced by these facilities are compounded when digital images come to them in any one of a dozen (or more!) file formats and color encoding schemes, sometimes without essential metadata.
With the participation of more than 50 of the industry's leading technologists and practitioners representing a wide range of technology, tools and service providers, the Academy Color Encoding System Project Committee developed detailed system requirements as well as a number of competing architectures and proof-of-concept prototypes. As ACES components are finalized and tested, the Academy has been providing them to the industry in the form of documentation, software tools and reference images. Several ACES components are now being standardized within two of SMPTE's Technology Committees: TC-10E (Essence) and TC-31FS (File Structures).
The Academy Color Encoding System: What It Is, What It Does
The Academy Color Encoding System is a set of components that facilitates a wide range of motion picture workflows while eliminating the ambiguity of today’s file formats. The basic ACES components are:
- A file format specification and open source implementation in the form of an enhanced and "constrained" version of OpenEXR, the popular high dynamic range image file format widely used in CGI applications (SMPTE ST 2065-1:2012 and SMPTE ST 2065-4:2013)
- A portable software programming language designed specifically for color transforms. Called the Color Transformation Language, or CTL, this technology is now a SMPTE Registered Disclosure Document (SMPTE RDD-15)
- Reference transforms for conversions among ACES-defined encoding schemes
- A set of reference images and calibration targets for film scanners and recorders
- Documentation on the architecture and software tools
ACES is designed to support both all-digital and hybrid film-digital motion picture workflows, and supports custom look development.
For more details on ACES, please see this presentation.
The Academy has made CTL available through an open source license, and is making additional ACES components and reference images available through a limited source license. The implementation of certain transforms in CTL and the application of ACES to digital motion picture production may require a license from third parties.
Other intellectual property declarations related to digital motion picture mastering have been submitted to the SMPTE Digital Cinema Technology Committee (TC-21DC). ACES components are going through a similar declarations process. Potential ACES adopters are directed to SMPTE for more information, and are responsible for determining intellectual property issues with respect to their use of ACES and its components.
ACES Developer Resources
The Academy has made available resources to assist those interested in implementing the Academy Color Encoding System. Please visit the ACES Developer Resources page to learn more about these resources and download the source code.