2017

Table Of Contents
Autodesk CTF File Format Version 1.3
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. All Autodesk extensions are marked with the
version in which they were introduced or updated. All other elements and attributes are part of the original
Academy/ASC format.
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.
Here is an example:
<?xml version="1.0" encoding="UTF-8"?>
<ProcessList id="7401489a-9e4d-441d-a8b7-795739801f4e" name="ACES to HD"
version="1.2">
<Info>
<Copyright>Copyright 2013 Autodesk, Inc. All rights
reserved.</Copyright>
<Release>2013.3.pr27</Release>
</Info>
<Description>ACES Reference Rendering Transform + HD video Output Device
Transform</Description>
<Description>aces_dev version 0.1.1</Description>
<InputDescriptor>Academy Color Encoding Specification
(ACES)</InputDescriptor>
<OutputDescriptor>HD (Rec 709) video</OutputDescriptor>
<LUT1D halfDomain="true" inBitDepth="32f" outBitDepth="32f"
rawHalfs="true">
<Array dim="65536 1">
0
1
1
<!-- 65533 lines omitted -->
</Array>
</LUT1D>
<Matrix inBitDepth="32f" outBitDepth="32f">
<Array dim="3 3 3">
0.9259999990 0.0379999988 0.0359999985
0.1299999952 0.8000000119 0.0700000003
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