ACES Isn’t About a “Look”—It’s About Freedom
Many filmmakers hesitate to adopt new technologies fearing creative constraints. But with the Academy Color Encoding System (ACES), the opposite is true. Even as ACES has a default rendering, it’s specifically designed to be a flexible technical framework, accommodating any creative vision through the utilize of Look Modification Transforms (LMTs).
Understanding the “Base Look” and Why It Matters
Every color management system has an inherent “base look” determined by its design choices. Traditionally, these choices were embedded in output transforms that map color spaces to displays. ACES’ architecture, however, separates the rendering transform from the look, offering greater control. Early versions of ACES faced criticism for their default rendering, but ACES 2 addresses these concerns with a modernized architecture and a more advanced color-appearance model, providing a better match across different displays—HDR and SDR alike.
LMTs: Your Creative Control Within ACES
Even with ACES 2’s improvements, the system is designed to be a baseline. Custom looks are implemented as Look Modification Transforms (LMTs). These transforms systematically change the appearance of ACES-encoded data before it reaches the output transform, allowing for consistent and reusable creative styles. Any adjustment away from the original ACES2065 data is considered a “look.”
Bringing Your Existing Looks into the ACES World
What if you already have a look you love, defined by a LUT? You can integrate it into an ACES pipeline using a “Hybrid Look” approach. This involves combining your LUT with the Inverse ACES Output Transform within an LMT. A new LMT Maker tool, slated for release in 2026, will automate this conversion process, exporting a CLF file from your LUT’s input and output color spaces.
Choosing Your Grading Workspace: ACEScct and Beyond
While ACEScct is the most common workspace for color grading within an ACES pipeline, it’s not mandatory. ACEScct’s log-like characteristics are familiar to colorists accustomed to traditional workflows. However, other options exist:
- ACEScg: A linear, wide-gamut space suitable for physically based corrections and adjustments like white balance.
- Non-ACES Working Spaces (Hybrid Look): Used when integrating pre-existing LUTs, temporarily transforming the image out of the ACES working space and back.
- Color Space Aware Controls: Modern color correctors offer controls that behave consistently regardless of the working space.
Integrating Existing LUTs and AMF Workflows
If you have an “LMT-like” LUT already, you can easily incorporate it into the AMF workflow. Simply add the .cube file to your color grading stack, and when exporting your AMF, the software will convert it to a high-precision .CLF file, mathematically mapped for proper application within the ACES2065-1 color space.
What to Do If Your Tools Don’t Support AMF
For tools lacking native AMF support—such as on-set monitors—you can “bake out” a LUT for that specific use case. This ensures your AMF-tracked color recipe remains the source of truth, while the baked LUT provides a practical workaround.
ACES 2: Is It Time to Upgrade?
ACES 2 offers significant improvements, including a new color-appearance based rendering and better perceptual matching across displays. The feedback from colorists and DPs has been positive. AMF is compatible with both ACES 1 and ACES 2, with the version tracked within the AMF itself.
AMF and Content Hub MPS Integration
AMFs can be uploaded into Netflix’s Content Hub, linking them with camera footage as a complete color record for each clip. Detailed implementation specifics are available in the Netflix MPS documentation.
Frequently Asked Questions
- Can I use ACES if I don’t like the default look? Yes, LMTs allow you to apply any creative look within the ACES framework.
- Can I bring my existing LUTs into ACES? Yes, using the Hybrid Look approach.
- Do I have to grade in ACEScct? No, but it’s the most common and practical workspace.
- What is an LMT? A Look Modification Transform is an ACES-to-ACES transform that systematically changes the appearance of ACES-encoded data.
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