The Color Compass: A Color Navigation System in a Dynamic Deliverable World

摘要

Color order systems were developed to aid in the quantification of color. Classic color systems such as Munsell and Ostwald relied upon a three dimensional model of color to visually conceptualize the color order, in the shape of a cylindrical atlas and a double cone, respectively. These systems can aid in designating absolute values and identifying manufacturing standards by numerical specifications. — However, the addition of multiple color targets, including wide-color-gamut (WCG) and high dynamic range (HDR), to motion picture deliverables now means that multiple versions of the same file will be delivered. A cohesion between assets is required, whether or not that is done with metadata in the case of Dolby Vision files, or with completely separate image sequences as may be the case with some providers. Using a numerical color order system does not help QC professionals, color pipeline engineers, or production creatives determine whether these multiple versions are in line with original creative intent. The paper proposes a visual color navigation system, which provides new vocabulary in order that shifts in color, lightness, and chrominance values be identified, related to original creative intent, and shared between creatives and engineers alike in motion picture applications. — The system revolves around a hue disc with four cardinal directions, indicating two axes of warmth to coolness (North-South and East-West). This color compass can be used as a navigational tool within any color encoding scheme or color space in use for a project. For example, the system can be used to discuss the g and j axes in OSA-UCS, the a* and b* axes in CIELAB, or the tritan and protan axes in ICtCp. The system also equates lightness to altitude values, so a user can describe “higher” or “lower” values as one might describe the altitude of terrain. Lastly, chrominance will be described as expanded or contracted, in relation to the original value. — The paper will include illustration of the system at work in different color spaces, in addition to using practical examples from the author's experience with over one hundred episodes of HDR content.