The directional arrangement of the illumination plays an important role on image contrast and sharpness of silver-based photographic film. This paper explores how the directional arrangement of light (directed or diffuse) affects cinematographic colors. The experimental results show that a consistent color difference can be observed between the image projected on screen (directed illumination) and the image acquired with a scanner (diffuse illumination), no matter how well the scanner is calibrated. This fact has to be properly considered in film scanning and color correction; otherwise early color films can be notably distorted during the digitization process.
Giorgio Trumpy, Rudolf Gschwind, "Conflicting Colors: Film Scanning versus Film Projection" in Proc. IS&T 25th Color and Imaging Conf., 2017, pp 188 - 191, https://doi.org/10.2352/ISSN.2169-2629.2017.25.188