Building Custom Colour Transforms

You can build a chain of colour transforms using the Custom mode of the LUT Editor. The transforms are applied in order from beginning to end. For example, you can build a colour transform that first modifies the gamma and then changes the primaries.

1. In the LUT Editor, set the LUT type box to Colour Transform.
2. Enable the Custom button.
3. Click Add to insert an empty row.
4. Click in the Type column and select a type:
   • Shared: The location for shared custom colour transforms (available to all applications that use Autodesk Colour Management).
   • Project: The project transform folder (saved and archived with the project).
   • Autodesk: The default location for preset colour transforms supplied with the application. See Autodesk Color Transform Collection.
   • Import: Browse for colour transforms on your file system. You can select native .ctf format files, as well as several other supported LUT and transform formats.
5. After you've selected a colour transform type, click in the Transform column and select a transform.

   Information about the transform and the operations it contains appears in the LUT Editor.

6. To add more transforms to the end of the chain, repeat steps 3 to 5.
   You can also:

   • Click in the Type or Transform columns again to change a transform in the chain.
   • Select a row and click Delete to remove a transform from the chain.
   • Use the Up or Down buttons to reorder the chain. Moving a transform up applies it earlier in the chain, and moving it down applies it later.
   • Use the visibility icon to mute a transform in the chain.
   • Enable the Invert button to invert the entire chain of transforms, or use the Invert column to invert individual transforms in the chain.
     Note: Some colour transforms are impossible to invert perfectly. This happens when they map multiple input colours to the same output colour, such as when transforming from a large space to a smaller space. It is analogous to the fact that you cannot convert from a 12-bit signal to 8 bits and back to 12 bits again without data loss. In these situations, the Invert option maps the original output colour back to one of the original input colours, but applying the forward transform followed by the inverse transform will inevitably change some colours.

Tip: You can create subfolders in the Shared or Project locations to define custom colour transform types.