The application ships with a default OCIO config preset: "ACES 2.0". This config provides support for working with a very wide selection of colour spaces. As with all OCIO configs, it organizes for end-users the following kinds of components:

• Displays: This is a list of display devices, each containing a set of views it supports.
• Views: The views provide operations such as ACES 2.0 Output Transforms that are paired with specific displays.
• Looks: The looks provide operators such as grades that are often inserted before views, but may also be applied separately. (Though no grades are provided in the default config.)
• Display Colour Spaces: The display colour spaces provide the transformations used for the display list along with transformations for other display-referred colour spaces.
• Colour Spaces: These are the transformations for all the scene-referred colour spaces.
• Named Transforms: The named transforms are stand-alone transforms that are not tied to a colour space definition. For example, a simple transfer function curve.

The following description does not attempt to cover every item in the config, but will review the overall capabilities and cover highlights.

Displays

The provided displays includes a large set of SDR and HDR options. The displays in this config do not clamp at black or white. This allows for the preservation of super-whites and sub-blacks. This is often useful, e.g., when converting between full and SMPTE/legal range or converting between different gamuts. However, care must be taken when monitoring on wide-gamut monitors, looking at vectorscopes, or when exporting. Numerous methods in the application may be used for clamping, if desired.

Noteworthy display options include:

• "Rec.1886 Rec.709 - Display": This is what is often called just "Rec.709", the broadcast HD video colour space. The "Rec.1886" refers to the EOTF transfer function expected to be used for the monitor, defined in ITU-R BT.1886, which is basically a 2.4 gamma.
• "sRGB - Display": This is the ubiquitous colour space used for displaying images on the web. This display has the so-called "piecewise" transfer function defined in IEC 61966-2-1:1999. If you need it, there is also a "Gamma 2.2 Rec.709 - Display" provided. This is often confused with sRGB, but it uses a simple 2.2 gamma rather than the correct piecewise function.
• "Display P3 - Display": This is the default for many Apple devices. This one only has SDR views defined. There is also a "Display P3 HDR - Display" which has HDR views defined. Note that you should set the macOS Display System Settings to use the "HDR Video" preset for the most accurate results.
• "ST2084-P3-D65 - Display": This is the display most often used for HDR mastering. The SMPTE ST2084 transfer function is also known as "PQ". This is the display that is used when you enable HDR mode for a monitor in the Flame Setup application.
• "Rec.2100-PQ - Display": This is the display for ITU-R BT.2100-PQ. It is a commonly used standard for HDR delivery.
• "Rec.2100-HLG - Display": This is a display that implements ITU-R BT.2100-HLG, assuming that the display is set up for 1000 nits. Given that appearance of HLG depends on the nit level, you may want to work using one of the other HDR display options and then convert to HLG on export.

Views

Most views convert from a scene-referred space such as one of the ACES colour spaces or the output of a digital cinema camera, to a display-referred space in preparation for sending to a monitor. This type of a transform is often referred to as performing a tone-mapping. This compresses the wide exposure range of a scene into the range of a display while also accounting for other factors such as the adaptation of the human visual system, stray flare light in the system, and aesthetic preference.

Noteworthy view options include:

• "ACES 2.0": A collection of the ACES 2.0 Output Transforms is provided for use on D65 displays. The naming scheme includes first the target nit level for the display and then the target gamut that the image will be compressed into. For example, "ACES 2.0 - HDR 1000 nits (P3 D65)" is targetting a 1000 nit output level and a P3 gamut. Please note that although the view is compressing to a P3 gamut, the display you use it with will determine what the encoding gamut is. For example, it is common to compress to a P3 gamut but deliver in a wider encoding gamut such as Rec.2100.
• "ACES 1.x": Several views are provided that implement the previous ACES releases. This may be helpful for backwards compatibility.
• "Un-tone-mapped": This view maps the scene-referred colorimetry directly onto a display with no tone-mapping. A linear value of 1.0 in the scene maps to a 100 nit white on the display. This is equivalent to what could be called a "simple linear workflow" or a "de-gamma/re-gamma" workflow. It is only available with scene-linear or log colour spaces.
• "Video (colorimetric)": This view accurately presents display-referred colorimetry on a display. In other words, the colour values, as described by the colour space the media is tagged with, are converted for display on a given monitor. This is similar to the ICC colour management used in many commonly used creative applications. It is only available for video colour spaces.
• "Low Contrast": There are a series of views that give a low-contrast, diagnostic view of an image that may be helpful when you want to assess the range of exposure information contained in an image.
• "Raw": This bypasses all colour management and sends the image directly to the monitor. This gives the same result as toggling the Active/Bypass switch in a viewport.
• "Matte": This is the view that is used with non-colour data such as mattes/alpha channels. This is different from the "Raw" view since it allows you to view mattes comfortably on HDR monitors, rather than blasting 1.0 out at some very high nit level.
• "Normals": This is similar to the "Matte" view but may be useful with CG passes such as normals that have lot of negative values.

Looks

Currently, the only look provided is "ACES 1.3 Reference Gamut Compression". This is an effect that will compress extremely saturated colours into the AP1 gamut used by the ACEScg colour space. Details are available in the ACES Reference Gamut Compression User Guide.

Colour Spaces

There is a large collection of display-referred and scene-referred colour spaces that have been provided. The naming largely follows the choices used in the OCIO CG and Studio configs developed by the OCIO ACES configs working group. The colour spaces are divided into the following families, as shown in hierarchical menus.

Broadcast

This family includes the ITU colour spaces for SDR and HDR video broadcast, including Rec.709 and Rec.2100.

Display

This family basically includes all of the display-referred colour spaces that are not in the Broadcast family. This includes display standards such as sRGB as well as colour spaces that are used in photography workflows.

Data

This family is only intended for tagging various types of CG or AOV passes, such as those output from Action. In addition, it contains the "Raw" colour space. A clip that is tagged with "Raw" will bypass all colour management.

Note that, unlike "Raw", the other data colour spaces do not bypass colour management in order that they may be viewed comfortably on HDR monitors. Effectively they are handled as if they were tagged as Rec.709, given that most people are used to looking at these without colour management on SDR monitors.

In addition, there is an "Unknown" colour space, which may be used to tag images where the colour space is unknown. It is also effectively handled as if it were tagged as Rec.709.

ACES

This family includes the standard ACES colour spaces. Noteworthy options include:

• "ACES2065-1": This is a very wide gamut, scene-linear colour space that is recommended for use in interchange or long-term archiving. When stored in uncompressed OpenEXR format, the files correspond to SMPTE ST-2065-4. Note that the AP0 primaries it uses is such a wide gamut that it is not ideal as a working space.
• "ACEScg": This is the recommended scene-linear working space in the ACES system. It uses the AP1 primaries as the gamut which strikes a good balance between being wide enough to capture a very good range of colours, while not being so wide that it's difficult to work with. It makes an excellent working space for doing CG rendering.
• "ACEScct": This is the recommended logarithmic working space in the ACES system. It also uses the AP1 primaries, but uses a transfer function similar to those used in digital cinema camera log formats. Unlike ACEScg, the code values are roughly perceptually uniform and therefore some algorithms work better in this type of space. It is a good choice for use in timelines in finishing projects.

Input

This family includes all the digital cinema camera colour spaces. The naming convention often uses the form Transfer Function followed by Encoding Primaries/Gamut. For each camera vendor there is a colour space that uses a logarithmic transfer function (for example: "S-Log3 S-Gamut3") and another that uses a linear transfer function (for example: "Linear S-Gamut3").

In addition to the colour spaces, there is often an OCIO named transform that just implements the transfer function as a stand-alone curve. The naming convention for these uses the name of the transfer function followed by "- Curve", for example: "S-Log3 - Curve". These are located in a "Curve" sub-menu.

The named transforms are not available for use when tagging a clip. However, they are available in the "Input Colour Space" menu when applying an input transform. What happens in this case is that the named transform (or curve) is applied, and the result is tagged based on the "Working Colour Space" menu. This allows you to easily apply a simple one-dimensional linearization in special situations, without doing a full colour space conversion.

Utility

The Utility family includes the colour spaces used for CG textures. There is a "Linear" sub-menu for linear encoding gamuts and a "Texture" sub-menu for colour spaces that use a non-linear transfer function encoding (i.e., gamma correction).

Note that these "Linear" and "Texture" colour spaces are scene-referred and are thus appropriate for use in CG rendering. Some of the Texture spaces are similar to ones in the Display family. The difference being that the Texture ones are scene-referred and the Display ones are display-referred. The appropriate tagging depends on the intended use.

For example, if you have an sRGB image that you intend to use as a texture in Action, you should tag it as "sRGB Encoded Rec.709 (sRGB)" from the "Utility/Texture" menu. However, if you have an sRGB video clip you intend to use in a Timeline, you should tag it as "sRGB - Display" from the "Display" menu. This ensures that the correct view transform will be used in the viewport.

In addition, the Utility family contains a set of OCIO named transforms, described in the next section.

Named Transforms

The default config contains a very large set of OCIO named transforms which are simple mathematical functions useful for a wide variety of purposes. A few of these are available for use in the "Input Colour Space" menu in Input Transform mode, but many are only accessible when using Colour Transform mode and enabling "Custom". They are divided into sub-menus, as follows:

• "Adaptation": Converts CIE XYZ values from one white point to another using either Bradford or CAT02 chromatic adaptation.
• "Channel-ops": Extract single R, G, B channels or compute a luma weighting.
• "Clamp": Various clamps at the dark end or the bright end (for PQ nit levels).
• "Curve": A wide variety of gamma curves and Log-to-Lin transfer function curves. The forward direction takes non-linear values as input and outputs linear values.
• "Gain": Apply simple multiplicative gain factors.
• "Levels": Convert from Full to SMPTE/Legal range or vice-versa, either with or without clamping. The "Lift Linear Camera Black" is useful to compress small negative values into positive ones without affecting values outside of the deep shadows.
• "Luma-Chroma": Conversions from gamma-corrected RGB video spaces to YCbCr. And conversions from CIE XYZ to various uniform colour spaces and Yxy (luminance and chromaticity).
• "Offset": Apply simple additive offsets.
• "Tone-map": Various one-dimensional tone-mapping curves.
• "View": Functions that are used to build various shared views.

Note that when building a custom Colour Transform, these may be applied in either the forward or inverse direction. For example, a multiply would become a divide and an addition would become a subtraction.