Color and Mastering for Digital Cinema

187 Pages·2007·3.284 MB·English

by  Glenn Kennel (Auth.)

Cover photograph: Standard Evaluation Material (StEM) picture by permission of the American Society of
Cinematographers (ASC) and Digital Cinema Initiatives (DCI). Color Timing Theatre is courtesy of
Laser Pacific Media Corporation.
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Preface
The standardization of 35mm film nearly 100 years ago paved the way for the growth of the
motion picture industry. From its humble roots in nickelodeons and peep shows, the motion pic-
ture business evolved into popular entertainment for the masses. Along the way, the 35mm film
standard was extended to support sound, color, wide screen presentation, and multi-channel
digital soundtracks.
The film-making process is being revolutionized by the adoption of digital imaging technologies.
Digital post production was widely embraced in the 1990s, and digital cinema distribution and
exhibition is now taking off with a consensus standard supported by all of the major studios.
This book describes the color mastering and encoding methods for digital cinema, looking back
at the traditional film process, providing insight into the evolving digital intermediate process,
and reviewing the basis for the color encoding standards for digital cinema distribution. One can
only hope that these digital cinema standards can be as capable and enduring as 35mm film.
ix
Acknowledgments
I could not have written this book without the help of many people. First, I’d like to thank my wife,
Sarah Priestnall, for checking my writing and correcting my mistakes, and also for helping me re-
write sections for clarity, particularly the chapter on Digital Intermediate. I also thank her for her
support and patience while I was spending many weekends on the writing.
I am deeply indebted to Tom Maier of Kodak for his lucid writing on the subject of color pro-
cessing for digital cinema. In particular, much of Chapters 3, 4, 7, and 8 are based on documents
that he wrote as a leading contributor to the SMPTE DC28 Color ad hoc group.
I also thank Matt Cowan of Real D for his contributions as a member of the SMPTE DC28 Color
ad hoc group, and for his help in reviewing and editing the chapter on Digital 3D. Matt also con-
tributed several illustrations to this book.
Brad Walker of Texas Instruments taught me a lot about the color processing that he designed for
the DLP Cinema® projectors, and much of Chapter 9 is based on a paper that he co-authored
with Greg Pettitt, also of Texas Instruments. Brad was also a key contributor to the SMPTE DC28
Color ad hoc group.
I’d also like to thank the other members of the SMPTE DC28 Color ad hoc group, who dedicated
many hours to our discussions and evaluations leading up to the specification of X(cid:2)Y(cid:2)Z(cid:2) color
encoding for digital cinema distribution. This group also included Prinyar Boon, Chuck Harrison,
Jim Houston, George Joblove, Howard Lukk, Arjun Ramamurthy, Jeremy Selan, John Silva, Kaz
Tsujikawa, and Ron Williams.
xi
xii Acknowledgments
I’d like to thank industry consultant Peter Putman for his contributions to Chapter 10 on Digital
Display Technologies. Many of the illustrations in this chapter come from his tutorials to HPA
and NAB audiences.
And finally, I’d like to pay a special tribute to Walt Ordway, Howard Lukk, and Jim Whittlesey of
Digital Cinema Initiatives, who drafted the DCI System Specifications, and in the process built a
technical and political consensus amongst the major studios, enabling the deployment of digi-
tal cinema.
About the Author
Glenn Kennel has worked in technology development in the motion picture industry for over 25
years, pioneering the application of digital technology to the filmmaking process He started his
career with Eastman Kodak in 1980, and participated in the development of Kodak High Speed
Negative Film 5293.
In the mid-1980s, Kennel assembled a project team and led the development of a prototype
HDTV telecine that later provided the basis for the Philips Spirit Datacine. In 1989, he worked
with Industrial Light & Magic (ILM) to build the first linear CCD scanner for motion picture film
scanning.
Kennel was also the architect of the Cineon digital film system in 1990 and led the development
of the Cineon CCD film scanner and film recorder over the next couple of years. He helped launch
Kodak’s Cinesite Digital Film Center in 1992 and evangelized digital technology with the visual
effects industry. He also provided technical support to Cinesite during the digital restoration of
Disney’s Snow White.
In 1993, Glenn Kennel was recognized by SMPTE with the Agfa-Gaevert Gold Medal for out-
standing achievement in the field of film/television interface.
In 1995, he received the Academy Scientific and Technical Achievement award for the linear
CCD film scanner, jointly developed with ILM. He worked with Philips to extend the Spirit
Datacine to Cineon-compatible digital file output, first applying it to the film “Pleasantville”
in 1997. He helped establish Cinesite’s Digital Mastering department in 1998, providing technical
support to the first major feature film to go through the DI process, “O Brother, Where Art Thou?”
in 1999–2000.
xiii
xiv About the Author
As program manager of Kodak’s Digital Cinema effort in 2000–2003, he led a team that developed
servers and software for digital cinema and coordinated a joint development program with JVC
for a digital cinema projector.
In 2003, Kennel left Kodak to work as an industry consultant with DCI on color encoding for dig-
ital cinema, including coordinating the digital mastering process for the ASC/DCI StEM test. He
chaired the SMPTE DC28 ad hoc group on Color and helped draft several digital cinema stan-
dards. He joined Texas Instruments’ DLP Cinema group in 2004, in a role that combined tech-
nology and business development for digital cinema, helping the industry address the practical
hurdles to digital cinema deployment.
Kennel was elected to the Scientific and Technical Branch of the Academy of Motion Picture Arts
and Sciences in 2005.
Kennel is now Vice President and General Manager of the Motion Picture division of Laser Pacific
Media Corporation, where he is responsible for services including digital dailies, previews,
Digital Intermediate, mastering and digital cinema packaging.
Kennel is the author of many technical papers on applications of digital technology to filmmak-
ing published in the SMPTE Journal, and co-author of a chapter in Understanding Digital Cinema
(2005). He is also a fellow of SMPTE.
About the Series Editor
Charles S. Swartz oversees efforts to further the entertainment industry through new technology.
He draws from more than two decades of experience in feature film and television production,
academic programming and strategic consulting to lead the center in identifying emerging enter-
tainment technology issues and developing projects to study them. Swartz assumed his current
position at the Entertainment Technology Center in 2003, where he has refocused and recharged
the research center. He serves in two positions for SMPTE/Hollywood: Governor of the Hollywood
Region and co-chair of the education committee. In 1996, the Los Angeles Business Journal
named him one of 100 technology leaders in Los Angeles.
xv
1
Overview of Color and
Mastering for Digital
Cinema
In June of 1999, George Lucas released his film “Star Wars: Episode 1” on two digital cinema
screens—one in New York and one in Los Angeles. In the five years since this historic debut, over
150 films have been released digitally to over 500 screens in 30 countries around the world. These
digital movies have played over 20,000 shows to satisfied audiences. Although digital cinema has
not been widely promoted as a new and improved display method, educated audiences have shown
a preference for digital over film presentation.
This book presents a survey of the development of color encoding and decoding standards for dig-
ital cinema distribution and exhibition. It describes the key issues and provides background on
decisions that were made in the standardization process. Although the author was a key participant
in the development of the SMPTE1DC28 documents, it is recommended that the reader refer to the
published SMPTE standards2for the final word on implementation.
1. Society of Motion Picture and Television Engineers.
2. At the time of this writing, the SMPTE DC28 working group has several digital cinema documents in process.
These standards are available to participants, but have not yet been published.
1
2 1. Overview of Color and Mastering for Digital Cinema
This book refers to colorimetric principles that are more rigorously defined in color textbooks3,4
and assumes that the reader has a working knowledge of basic color principles and motion picture
industry practices. However, one does not need to be a color scientist or industry insider to read
and understand this book.
In late 1999, SMPTE established the DC28 working group to study the standardization requirements
for digital cinema distribution, with the goal of establishing a world-wide standard. Since its stan-
dardization by SMPTE in 1916, the 35mm motion picture film format has served as the single world-
wide distribution standard for movies. 35mm motion picture film has weathered the test of time,
supporting major exhibition enhancements like sound, color, widescreen presentation and multi-
track digital soundtracks, all compatible with 35mm projection equipment based on the original
standard. In today’s hyper-competitive and fast-changing digital world, it seemed a tall order to
establish a digital cinema distribution standard that would serve the industry for the next century.
But the industry set its sights on just that. The goal was to develop a universal standard for digital
cinema distribution that could be implemented in a cost effective way today, while also extensible
to support future exhibition improvements.
The SMPTE DC28 group concluded its study work at the end of 2000 by identifying the need for
standards for digital cinema mastering, distribution and exhibition. Working groups were estab-
lished to address each of these areas. In addition, ad hoc groups of industry experts were formed
to address specific issues, including packaging, key management and security, and color. The DC28
color ad hoc group began its work in 2002, focusing its initial discussions on the color encoding for
digital cinema. The group was composed of experts from diverse parts of the industry that included
studios, post production facilities and equipment manufacturers. While everyone agreed on the
goal, there were many opinions on how best to get there.
While the SMPTE DC28 work proceeded slowly and steadily as a due process forum with diverse
interests, the establishment in 2002 of the Digital Cinema Initiatives, LLC (DCI), a consortium
formed by seven major Hollywood studios, provided a focus for the development of the digital cin-
ema standards. A group of technical experts from the member studios met regularly to hammer out
a consensus technical specification for digital cinema distribution. In its work, DCI used available
and prototypical digital cinema equipment to evaluate requirements for compression, security,
content packaging and color encoding. DCI hired several industry experts to supplement its inter-
nal expertise. Amongst other things, DCI funded the Contrast Sensitivity Test that verified the bit
depth requirement for color encoding (see Chapter 4).
Most importantly, DCI provided a venue for the political process of building consensus amongst
its members. Its crowning achievement was the delivery of a consensus technical specification for
3. R.W.B. Hunt, The Reproduction of Color, 6th Edition, Wiley, © 2004.
4. G. Wyszecki and W.S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulae, 2nd Edition,
Wiley, © 2000.