The Academy Color Encoding System (ACES) is an image interchange framework developed under the auspices of the Academy of Motion Picture Arts and Sciences.

At the core of the ACES system is the Academy Color Encoding Specification (also known as ACES2065-1). This is an extremely wide-gamut scene-linear space that can encode any visible colour without using negative values. It is ideally suited for safe and unambiguous interchange and long-term archiving of images.

In addition, ACES recommends two working colour spaces:

• ACEScg is a scene-linear working colour space
• ACEScct is a logarithmic working colour space

The ACES system also includes a set of colour transforms that provide a best-practice for colour managed workflows:

• Input Transforms are provided for all major digital cinema camera colour spaces to convert to ACES2065-1. (These were previously called an "IDT".)
• Output Transforms are provided for all major display devices and delivery colour spaces used in the motion picture and television industries that convert from ACES2065-1 to display code values. (These were previously called an "RRT+ODT".)

The ACES project collaborated with the American Society of Cinematographer's technology committee on the development of the Common LUT Format (CLF). This is more than just a LUT format, it is a powerful colour transform format specifically designed to work with floating-point high dynamic-range colour spaces. (OCIO fully supports CLF, which is a subset of the CTF format.)

The ACES project worked with the OpenEXR project to define a constrained version of the OpenEXR format for storing images in ACES2065-1 colour space for interchange and long-term archiving. This format was standardized as SMPTE ST2065-4.

There is a lot of information about ACES available on the web:

• The main website for ACES is ACES Central.
• Technical documentation may be found on this ACES Central page and additionally in the SMPTE ST-2065 suite of standards.
• The American Society of Cinematographers has a page on ACES.

ACES in Flame

All of the aspects of ACES mentioned above are fully supported in Flame Family applications. The colour management is provided via OpenColorIO. The ACES and OCIO projects collaborate closely to ensure that OCIO provides a complete and high quality ACES implementation. OCIO now implements all ACES transforms via shaders rather than LUTs for improved accuracy.

The default config provided with the application is based on ACES 2.0.

ACES 2.0

ACES 1.0 was released in 2014. At NAB 2025, the Academy launched ACES 2.0. The main new feature is a completely new set of Output Transforms.

The new ACES 2 Output Transforms are the result of a multi-year development process that took advantage of the latest research into colour appearance modelling. The benefits over ACES 1 are:

• Better handling of extreme colours such as neon lights, emergency vehicle lighting, etc.
• Better invertibility of colours near the edge of the SDR gamut (e.g., colour bars).
• Improved match between SDR and HDR output.
• Improved gamut mapping.
• Support for additional display devices.

The "look" of the ACES 2 tone-mapping is somewhat different than ACES 1. The most noticeable difference is a reduction in contrast from middle grey into the highlights. As a result, a much brighter scene-referred value is needed in order to get to the pure white of a display. In some cases, additional grading may be needed to get to the desired level of contrast. The reproduction of elements such as fire and sunsets is also somewhat different.