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# Autodesk CTF File Format

There are a wide variety of colour transform (also known as "LUT") formats used in the media and entertainment industry. This creates workflow problems since you may receive a LUT which is not supported by one or more of the applications you use. Furthermore, most of these LUT formats are based on out-dated technology and lack the quality, flexibility, and metadata needed to meet today's requirements.

To address these problems, the technology committees of the Academy of Motion Picture Arts and Sciences and the American Society of Cinematographers convened a group of experts to design a common transform format that could become an industry standard.

Autodesk has chosen to adopt this format as the native format for our colour management technology and we provide a large collection of transforms in this format with our applications (e.g., to support the Academy Color Encoding System).

This guide provides information about the Academy/ASC format to help you author your own colour transforms. In addition it defines several Autodesk specific extensions which you may use when authoring colour transforms solely for use in Autodesk applications.

#### Topics in this section

- Anatomy of a CTF File

  The transform format allows the author to define an arbitrary chain of color operators (also called processing nodes). The set of available operator types includes 1D LUTs, 3D LUTs, matrices, and others defined below. The format is written in XML and is therefore human readable.

- CTF Syntax Summary

  Here is a brief overview of the syntax of a CTF file.

- XML Declaration

  The XML declaration is optional but recommended. It indicates to the XML parser the version of XML and character encoding used.

- ProcessList

  The ProcessList element is the root element of a CTF file. It must contain at least one operator element.

- Metadata Elements

  The metadata elements provide information about a color transformation that can be displayed in information panels in applications.

- Operator Elements

  The operator elements specify the operations to be applied to the color data. You can have as many as you like in a ProcessList element, in the order in which they are to be applied.

- Comments

  You can include standard XML comments in CTF files.