Define Criteria for Transform Inclusion in ACES Repositories

[scottdyer]

Currently, the ACES sub-repositories contain a curated set of transforms, but lack a clearly documented policy for what transforms should or should not be included. This has consistently led to confusion among implementers, users, and project maintainers.

The transforms are intended to serve as standard building blocks and to demonstrate best practices for implementers.

But some users have assumed that if a transform is not included in the repo, then it cannot or should not be used. The absence of a transform in the ACES repository does not imply that it is invalid, discouraged, or prohibited. Implementers and users have always been free to develop and employ additional transforms that meet their specific workflow or creative requirements.

In addition, some users would prefer to have more transforms so they do not need to "roll their own". (either because doing so is either too much extra work, or because the guidance is not there to allow them to feel enabled to do so).

Users might want to contribute custom transforms they have created and found useful, but are unsure if or how they will be accepted.
And implementers or product manufacturers may want to contribute new transforms for a new camera or display.

Therefore, the project needs to establish:

1. Criteria for inclusion of transforms in the official repository.
2. Best practices for managing, versioning, and documenting transforms outside of the official set.
3. Communication strategies to clarify what is the set of "reference" transforms while maintaining flexibility for additional transforms.

[scottdyer]

I will note that the README files in aces-output, aces-look, and aces-input-and-colorspaces previously stated the following "policy":

Contrib directory

The contrib directory contains community-supplied transforms, provided as-is and may not be optimal. The ACES team may have done minimal testing on these transforms, but please visit ACESCentral.com to review or leave feedback.

Note to Implementers

Implementation Guidelines

• Primary Transforms: The transforms located in each of the subdirectories of the root directory, with the exception of the contrib directory, are a basic subset of possible outputs and should be implemented in all ACES systems. These subdirectories contain the standardized, validated transforms necessary for maintaining compatibility and functionality across different platforms and devices.
• Community Contributed Transforms: The contrib directory contains additional community-supplied transforms. These are considered optional. They may provide useful extensions but vary in their testing and support. It is advisable to evaluate their reliability and suitability for your specific needs before integration.
• Updates and Maintenance: Ensure your system includes the most recent updates by regularly incorporating new or revised transforms from the main subdirectories, keeping in line with the latest ACES specifications and industry practices.

I removed these statements during the preparation of the repositories for transfer to ASWF for a couple of reasons:

1. This does not define what would qualify a contributed transform to cross over into the primary transforms.
2. There were no contents in any of the contrib directories, and it made sense to me to remove them to avoid confusion, and add back once once the project can clarify this previous language or establish a new, clearer policy.

[scottdyer]

Without clear criteria, the project risks drifting toward one of two extremes:

1. Accepting all possible transforms
   • risks creating overly long lists of transforms
   • creates confusion for implementers about which transforms are "required" vs "optional"
2. Restricting new transforms without explanation
   • may cause the impression that external/custom transforms are not permitted
   • could limit adoption by limiting availability of custom transforms a production might need hosted by the project to comply with internal workflows rules

The project should focus on establishing a clear decision-making process and inclusion criteria for transforms in the ACES repositories. This should include:

• Clarify contribution policy
  • Define whether custom transforms may be contributed.
  • If so, what is the review/acceptance process?
• Determine inclusion criteria
  • Define what qualifies a transform for the "primary" transforms vs "contributed" transforms
    • Is it broad industry use or consensus? Archival importance? Specific needs from productions?
  • Clear inclusion criteria should:
    • help maintainers handle new submissions or requests for transforms more quickly and consistently
    • provide transparency to how inclusion decisions will be made
    • reduce confusion for implementers and end users
• Provide guidance for custom transforms
  • Clearly state that productions and implementers can create and use their own transforms, even if not in the official repository.
  • However, we will need to consider
    • Potential complications when using custom transforms with tools that don't easily support the adding of custom transforms.
    • Best practices for managing custom transforms in collaborative workflows using AMF.