This book is about hands-on visual effects compositing techniques, in the quest for photorealism for feature film and HDTV visual effects. This, the fourth edition, is not just an update but a major rewrite with three major thrusts – step-by-step workflow examples, the addition of several powerful new techniques for keying, and the latest VFX industry tech. I have 20 years “in the chair” doing visual effects compositing for over 70 feature films so I have brought a wealth of real-world production experience to this book. Due in large part to the first edition of this book, in 2005 I turned to teaching and training visual effects compositing and developed a unique understanding of what compositing artists really need to know to achieve employment in the visual effects industry.
Of course, artistic training is an essential ingredient to achieving photorealism since it is in the art class that you learn how things are supposed to look. But the other requirements are a mastery of your tools and of technique. Knowing what the picture should look like will do little good if you can’t bend the images to your vision. Reading the owner’s manual will teach you how to operate your compositing software, but it will not teach you how to pull a good key from a badly lit bluescreen, or what to do when banding erupts in a digital matte painting. It is the difference between the owner’s manual for a car and driving school. The first teaches you where the knobs are and the second how to use them to actually get somewhere.
While very suitable for beginners, this is not an introductory book. It assumes that the reader already knows how to operate the compositing software, what a pixel is, and what RGB means. It is intended for the digital artist sitting in front of a workstation with a picture on the monitor wondering why there are edge artifacts in a bluescreen composite and how to get rid of them. The attempt was to present the topics with sufficient background detail that they will be of value to the beginner, while including advanced concepts and production techniques that will also be of value to the more-experienced compositor.
This is also a software-agnostic book. It carefully avoids the specifics of any particular brand of software and uses procedures and techniques such as rotoscoping, tracking and color correcting that are common to all software products. You will be able to perform all of the procedures in this book regardless of the brand of software that you are using, including Adobe Photoshop. Photoshop has become an important tool for pre-visualizing visual effects shots, so it would be very useful to know how to use it to pull a color difference matte and perform the despill for a bluescreen shot. Better yet, we will see how to take the art director’s “look dev” where he previewed a shot for the nice client in Photoshop and match it perfectly in your compositing software even though it works in a different color space and may not even have some of Photoshop’s advanced blend modes. No problem.
Each topic has two thrusts. The first is understanding how things work. It is much more difficult to solve a problem when you don’t know what is causing it, and a large part of time spent in comping a shot is problem solving. There is a great deal of information on different ways to pull a key, how despill works, and what goes on inside of a compositing node. The purpose of all of this information is to provide sufficient understanding of the issues that conspire to spoil your fine work, so that when you encounter a production problem you will be able to stab your finger in the air and declare “I know what’s wrong here!”, then turn around and fix it straight away instead of fumbling around for hours, or worse, introducing compensating errors in a vain attempt to make the problem go away.
The second thrust is production technique. How to sweeten a bluescreen so your keyer will pull a better key, how to do photorealistic color correction, how to manage lens distortion between the different layers of a comp, to cite just a few examples. There are dozens of step-by-step procedures to walk you through complex workflow issues like grain management for a multilayer comp, or the proper math ops to use for compositing mult-pass CGI renders. There is an entire section on the various types of artifacts introduced by lenses with the procedures for how to replicate them in your software so that you may add an additional level of photorealism to your comps.
The third thrust of this book is to bring you up to speed on all of the latest technology being used for compositing visual effects today such as AOVs for CGI compositing, 3D compositing, the use of Alembic geometry, OpenColorIO, and ACES, the awesome color management system created by the Academy of Motion Pictures Arts and Sciences specifically for feature-film visual effects. There is even a sneak preview of the near future of visual effects for when light field cinematography comes on line in the next few years. This astonishing technology will revolutionize visual effects. Be ready.
While the information and techniques described herein apply equally to film and video work, the focus of the book’s presentation is feature film, simply because it is the most demanding application of visual effects. The much greater resolution and dynamic range of filmmaking make it more challenging to achieve excellent results so it is the “gold standard”. HD video is, of course, extremely important, so it gets its own special section detailing its special issues such as limited dynamic range, interlaced images, chroma sub-sampling, and other technical delights.
By virtue of gaining a deeper understanding of how things work my hopes for the reader of this book are threefold. That you will finish your comps faster, that they will look more photorealistic, and that you will have more fun in the process. Let’s face it. What could be more rewarding than putting together a beautiful shot to be admired by millions of viewers? Enjoy.