You can work with user-defined color transforms instead of, or in addition to, the built-in color space options. Once you have added a user transform, it appears on the appropriate menus.
Your transform can be a SynColor .ctf file, or in any of a variety of third-party formats. See Supported Color Transform File Formats.
User transforms are stored as .ctf files in the User Transform/LUT Directory Path set in your Color Management preferences . They consist of a reference to the file that contains your transform, which may be stored in any location. In addition, user transforms include additional metadata, such as the input or output color spaces. The metadata allows Autodesk Color Management to automatically construct a chain of transforms to convert from one color space to another via connection spaces.
You cannot work with user transforms if you are using SynColor with an OCIO v1 configuration file for color management. When using an OCIO configuration file, only the color transforms specified in the configuration file are available.
Color spaces are matched by name. If you open a scene that uses unavailable user transforms, a message appears. Any missing input color spaces used by File textures and other nodes are highlighted in red in the Attribute Editor. In addition, any missing color spaces in image input nodes are highlighted in red in the Attribute Editor and no transformation is applied. See Fix missing color transforms.
You can also use the Output Transform menu in the Color Management group of the Common tab of the Render Settings window.
Removing a user transform removes the .ctf file with the reference to a transform from the User Transform/LUT Directory Path, but does not remove the referenced transform itself.
You cannot remove any of the built-in transforms.