The Science and Technology Council of the Academy of Motion Picture Arts & Sciences is developing an architecture for digital motion picture mastering applications known as the Image Interchange Framework. As part of the architecture, a new optical printing density metric called Academy Printing Density (APD) and a new density encoding specification known as Academy Density Exchange Encoding (ADX) have been proposed. This paper will outline the need for a new printing density metric and encoding and detail many of the considerations in their design.
Alexander Forsythe, "Considerations in the Design of a New Printing Density Metric and Encoding for Contemporary Motion Picture Applications" in Proc. IS&T 17th Color and Imaging Conf., 2009, pp 296 - 300, https://doi.org/10.2352/CIC.2009.17.1.art00054