Logarithmic and Linear Colour Spaces

Lustre supports grading in a variety of colour spaces, including logarithmic and video colour spaces. The colour grading toolsets are dependant on whether the Grade Setup is in Logarithmic or Linear mode. In Log mode, the toolset is designed for digitized film images or digital cinema cameras working in a Logarithmic colour space. In Linear mode, the toolset is designed for video (that is, signals that you would send directly to a video monitor or digital cinema projector).

Note: There has been considerable confusion in the industry over the term "linear". Historically, "linear" been used to refer to either video colour spaces or scene-linear colour spaces (that is, spaces that are radiometrically linear or based on scene exposure). In Lustre, the term "linear" refers to video-type colour spaces.

Lustre also supports grading of floating-poing scene-linear colour spaces. In this case, the Float Conversion LUT in Calibration Settings allows fine-tuning of the response of the grading controls. The Logarithmic grading toolset is best suited for grading scene-linear data. However, either toolset may be used with any colour space, so ultimately this is a colourist's choice.

Lustre offers a variety of tools for converting various inputs into a working colour space. The Image Input LUT panel allows applying traditional "Log-to-Lin" transforms and legacy 1d or 3d LUTs. The newer Image Transcode LUT Options panel (available for media imported via the Gateway) supports a wider selection of LUT formats and provides access to the Autodesk colour transform collection, including support for ACES input transforms.

See Autodesk Color Management for more background information on choosing a working space and converting between colour spaces.