ACES from Theory to Making IDTs

Presenter: Charles Poynton
Duration: 2 days
Date/time: Thu/Fri, Oct 29/30, 2015, 9:00 ‑ 17:00
DFFB/UP.GRADE, Potsdamer Platz, Berlin

This workshop follows on from in-person workshops presented in Toronto, Vancouver, Montréal, New York, Los Angeles/Burbank, Munich, and Berlin.

A 2-page flyer [PDF] is available.


For nearly 20 years, cinema production and post-production was based upon the conceptual model of film acquisition: Even if image data was digitally acquired, the typical Cineon/CPD coding incorporated the technical parameters of film; in particular, the S-shaped tone response and the colour crosstalk of film. The CPD scheme made CGI and VFX difficult.

Digital cinema cameras are now commonplace; however, image data encoding is diverse and nonstandard. Some cameras generate data roughly comparable to a film scan (e.g., ARRI log C); others generate data comparable to HD (BT.709/BT.1886), or are based upon HD video (Hypergamma). “Log” formats of various kinds (e.g., Sony log, Red log). DI houses and CGI/VFX facilities have to deal with image data in new forms.

The Academy of Motion Picture Arts and Sciences (AMPAS) has released ACES 1.0, which defines a pipeline to acquire and process “scene-linear” data – that is, image data closely coupled to scene exposure. Colour transforms imposed during the DI process create the desired “look” and systematically compensate for the viewing conditions of cinema. The ACES scheme is being deployed commercially.

In this workshop, Charles Poynton will discuss the technical and visual requirements for acquisition and processing using the ACES scene-linear model. He will introduce the basic technical parameters of various camera encodings and describe their dynamic range and noise properties. He will describe the input device transform (IDT) by which image data from different cameras is trans­formed to a common colourspace (ACES). He will outline how “picture rendering” is imposed in the DI pipeline by the ACES reference rendering transform (RRT). He will describe ACES log coding (ACESlog, ACESproxy), the ACES colourspaces (AP0, AP1), and describe the four key colour transforms in ACES: IDT, LMT, RRT, and ODT. He will explain how the scene-linear model is applied to the DI pipeline, and how it aids CGI/VFX integration. He will describe various output device transforms to yield imagery suitable for D‑cinema, HD, and other displays. There is a significant hands-on component to the workshop. If you wish, bring your own camera and/or your own computer: We will have lights and colour charts, and toward the end of the workshop you can use what you’ve learned to make an ACES IDT for your own camera.

Who Should Attend: The workshop will be suitable for people in positions such as these:

Participants should be familiar with digital video/HD/UHD, with digital cinema, and with the rudiments of acquisition and colour grading. Knowledge of mathematics isn’t required, but will certainly be useful; many graphs and equations will be shown!

Registration: EUR 450. Detailed handout notes – some of which form portions of the second edition of Mr. Poynton’s book – will be provided. For further information, communicate with Charles Poynton in Toronto or Christiane Schweda in Berlin, +49 30 25759 121. To register, communicate with Christiane Schweda.

Copyright © 2015-09-25 23:37 EDT
Charles Poynton