In the context of the Academy Color Encoding System (ACES), a Look Modification Transform (LMT) is a tool used to apply creative or technical adjustments to the viewing transform stage of the image pipeline. The LMT allows cinematographers, colourists, and other professionals to introduce artistic enhancements or correct specific aspects of the image without altering the underlying colour science of ACES. It serves as a flexible layer for creative grading, enabling the adjustment of contrast, saturation, and other image attributes while maintaining the consistency and interoperability provided by the ACES colour management framework. The use of LMTs contributes to a standardized and efficient workflow in the production and post-production processes within the ACES ecosystem.