An Experiment in Digital Intermediate Color Management Using ICC Profiles

摘要

Traditional color management for visual effects feature-film production relied on output-referred techniques derived from film laboratory process control. The introduction of HDTV-originated content and a new goal of transferring the HDTV 'look' to film caused us to try and move beyond process control, and to experiment with graphic arts color management technology and techniques in our application domain. A feature-length motion picture, shot with HDTV cameras, was successfully recorded to film using a new workflow based on spectral measurement, CIE colorimetry and ICC profiles. The path to delivery was a challenging one. In retrospect it is unclear whether off-the-shelf tools for the ICC-profile-based workflows of the graphic arts industry can be made to naturally encompass video encodings with legacy broadcast encodings, or films with extremely nonlinear reproduction characteristics in regions of shadow or highlight. There are also unique challenges in the metrology of projected film. This paper describes some of the metrology and processing innovations we developed to support the abovementioned transfer. Although the client response was positive, the internal experience of production using an ICC-profile-based workflow was not uniformly so. It seems likely that in the near future, a hybrid approach combining laboratory process control techniques with colorimetric measurement and modest color appearance modeling may succeed where a pure ICC-profile-based system did not.