Difference between revisions of "UM:ACES"

The Academy Color Encoding System (ACES) is the industry standard for managing color throughout the life cycle of a motion picture or television production. From image capture through editing, VFX, mastering, public presentation, archiving and future remastering, ACES ensures a consistent color experience that preserves the filmmaker’s creative vision. In addition to the creative benefits, ACES addresses and solves a number of significant production, post-production and archiving problems that have arisen with the increasing variety of digital cameras and formats in use, as well as the surge in the number of productions that rely on worldwide collaboration using shared digital image files.

ACES is a free, open, device-independent color management and image interchange system that can be applied to almost any current or future workflow. It was developed by hundreds of the industry’s top scientists, engineers and end users, working together under the auspices of the Academy of Motion Picture Arts and Sciences. [ Source ]

Digital Vision Nucoda and Phoenix support ACES version 1.0.2.

A color space that includes the entire visible spectrum is the heart of the new workflow. ACES uses RGB values that are compatible with existing processing systems. The big change is that ACES images are scene referred meaning that light is accurately recorded as it existed at the camera focal plane, regardless of how that might look when viewed in its raw state or indeed independent of any output format or display device.

ACES files are frame based and a proposed replacement for the .dpx format. The ACES file format is derived from OpenEXR, developed by ILM and is a half float format with the extension .exr. However, ACES files contain a metadata flag that identifies them as ACES originated files. In short all ACES files are .exr, but not all .exr files are ACES.

A calculation to convert a camera, scanner or other image source to the Academy Color Encoding Specification, at which point the image will be scene referred and in an RGB floating-point format. Each device will need its own Input Transform (IT), and scene referred means that even exposure affects the transform.

Maps the ACES images to an ideal display format such as Rec709. Each display will need its own Output Transform (OT). Real world displays will still need calibration to exactly match the ideal color space of each transform.

This allows the colour tools to respond in a more familiar way to the colourist than they would in a linear space. The preview is removed before the Display Transform is applied.

ACES projects are created following the usual project rules but with a few new considerations detailed below.

From the Colour Space menu, select : ACES

Selecting ACES will set the project Bit Depth to Half automatically. Select the ACES version to use e.g. V1.0 Select your Working Space (see description above) : ACES ACES Gamma 2.2 ACEScc

Your main output format will have the selected Output Transform applied for preview purposes. Any media exported will not have transforms applied. Use this option to create archive masters in ACES 2065-4 container - export as EXR with 2065-1 option selected. Note that the output formats shown on the right have been renamed to reflect their settings
You can add additional output formats. To render the output transform into the media, select the desired output format and enable the Apply CMS button. Multiple output formats makes it easy to set up deliveries to multiple output targets and resolutions.

Having chosen ACES, the version and Working Space, you can select the preferred Output Transform for each output format you created. Nucoda ships with 64 point LUTs for the output transforms.

Output Transforms available in Clip Properties : Rec.709 Rec.709 Clip Rec.709 D60 Rec.709 D60-Clip P3-D60 48n P3-D60-ST2084-1000n [*] P3-D60-ST2084-2000n [*] P3-D60-ST2084-4000n [*] P3-D65-ST2084-1000n [*] P3-DCI 48n Rec.2020-D65-100n Rec.2020-ST2084-1000n [*] DCDM-D60 DCDM-P3-D60 RGBmon-D60-100n RGBmon-D65-100n [*] Suitable for HDR work - using PQ Capable monitor such as Sony X300 . Ensure that Bit Depth is set to Half for each output format.

Depending on the media you are using you can use the Clip.prefs file to set media to Half on application import.

If you prefer to work the usual way :

• Conform your material as normal and make sure all the media is available in the library.
• Sort and group media by type and place into directories to aid with organisation.
• Multi-select the image clips (make sure no audio or composition clips are selected) and select the properties button.
• In the properties, set the Bit Depth to Half
  • If all the media is the same type, you can set the Input Transform to the required setting.

The following Input Transforms are available to the user in the Properties menu of clips in the media library :

RAW Formats :

Non-RAW Formats :

The following Inverse Transforms are available from the Input Transform menu in File Properties. They are designed to attempt to invert the Output Transform that has been included in the rendered file (baked in). Inv Rec.709 Inv Rec.709-D60 Inv P3D60-48n Inv P3DCI-48n Inv DCDM Inv RGBmon-D60sim-100n Inv Rec.2020-100n Inv Rec.2020-ST2084-1000n Inv P3D60-ST2084-1000n Inv P3D60-ST2084-2000n Inv P3D60-ST2084-4000n

The following Look Modification Transforms (LMTs) are available to the user as LUTs :

• ACES_0_1_1.a1.0.2
• ACES_0_2_2.a1.0.2
• ACES_0_7_1.a1.0.2

LMT or Inverse Transforms in Nucoda are applied via the CMS effect. The option Apply in ACES Linear needs to be enabled to ensure that the transform is applied in the right part of the colour rendering pipeline.

Arri Log-C material with no Input Transform and no Output Transform
Arri Log-C material with no Input Transform applied
Arri Log-C material with Input Transform applied and Output Transform enabled

• The ACES technology site
• ACES technical documentation on Github