Digital Compositing for Film and Video

"This book covers both the basic fundamentals and the advanced techniques of compositing, but Steve also presents the reader with a deeper background on the task at hand. You're not just getting a how-to manual, but an understanding of why you do it." Patrick Tubach, VFX Supervisor, Industrial Light & Magic "Digital Compositing for Film and Video is the must have book for all compositors at all levels. I always keep copies close on hand for my artists to use and still refer to it often myself. The book covers the skills all compositors must know and the techniques needed when you are fighting tricky shots." Jeffrey Jasper, CTO, JTS Productions, LLC "Whats astounding about this book is that, for the last 16 years, every edition has been ahead of its time in terms of teaching and explaining the different techniques, technologies, and tools used on a daily basis by compositors around the world. Steve Wright has managed, once again, to stay ahead of the game and spearhead the education of current and future compositors." Ara Khanikian, VFX Supervisor, Rodeo FX

Steve Wright is a visual effects pioneer and a 20-year veteran of visual effects compositing on over 70 feature films and many broadcast television commercials. With extensive production experience and a knack for the math and science of visual effects he is a world-recognized expert on visual effects compositing. Since 2005 he has been a master trainer in compositing visual effects, providing staff training to over 25 visual effects studios around the world including Pixar Animation Studios, Disney Feature Animation, Troublemaker Studios, New Deal Studios, and Reliance MediaWorks, along with many others. He has also trained over 1,000 artists in compositing. Visit Steves training website at www.fxecademy.com

About the Author Acknowledgements Preface Chapter 1 - Getting Started 1.1 How this Book is Organized 1.2 Web Content 1.3 Whats New in the 4th Edition 1.4 Gold Mines 1.5 Tool Conventions 1.5.1 The Slice Tool 1.5.2 Flowgraphs 1.5.3 Color Lookup Tables (LUTs) 1.5.4 Nuke 1.6 Data Conventions 1.6.1 Floating Point Data 1.6.1.1 Banding 1.6.1.2 Clipping 1.6.2 Linear Light Space 1.6.3 HDR Images 1.6.4 Stops PART I MAKING A GREAT COMPOSITE Chapter 2 - Pulling Keys 2.1 Lumakeys 2.1.1 How Lumakeys Work 2.1.2 Making Your Own Luminance Image 2.1.2.1 Variations on the Luminance Equations 2.1.2.2 Non-luminance Monochrome Images 2.1.3 Making Your Own Lumakeyer 2.2 Chromakeys 2.2.1 How Chroma Keys Work 2.2.2 Making Your Own Chroma Keyer 2.2.3 Making a 3D Chroma Keyer 2.3 Difference Mattes 2.3.1 How Difference Mattes Work 2.3.2 Making Your Own Difference Matte 2.3.2.1 Making the Difference Image 2.3.2.2 Making the Difference Matte 2.4 Bump Mattes 2.5 Color Difference Keys 2.6 The "Blur and Grow" Technique 2.7 Rotoscoping 2.7.1 Control Point Coherency 2.7.2 Shape Breakdown 2.7.2.1 Hierarchical Articulation 2.7.2.2 Organization 2.7.3 Bezier or B-spline? 2.7.4 Keyframe Strategies 2.7.4.1 On 2s 2.7.4.2 Binary Multiples 2.7.4.3 Bifurcation 2.7.4.4 Motion Extremes 2.7.5 Motion Blur 2.7.5.1 Spline Placement 2.7.5.2 Edge Decontamination 2.7.6 Inspection Chapter 3 - Working with Keyers 3.1 Keyers 3.2 How Keyers Work 3.2.1 Calculating the Color Difference Matte 3.2.1.1 The Theory 3.2.1.2 Pulling the Raw Matte 3.2.1.3 A Simplified Example 3.2.1.4 A Slightly More Realistic Case 3.2.1.5 And Now, the Real World 3.2.1.6 Matte Edge Penetration 3.2.2 Scaling the Raw Matte 3.3 The After Effects Keyer 3.3.1 Step-by-step Procedure 3.3.2 Flowgraph of the After Effects Keyer 3.4 Typical Greenscreen Problems 3.4.1 Overexposed 3.4.2 Underexposed 3.4.3 Impure Greenscreens 3.4.4 Uneven Lighting 3.5 Preprocessing the Greenscreen 3.5.1 Denoise and Degrain 3.5.2 Screen Leveling 3.5.3 Local Suppression 3.5.4 Channel Clamping 3.5.5 Channel Shifting 3.5.6 Screen Correction 3.5.6.1 Step-by-step Procedure 3.5.6.2 Pictographic Flow Chart 3.5.6.3 Flowgraph of the Screen Correction Procedure 3.5.6.4 How to Create a Clean Greenscreen Chapter 4 - Refining Mattes 4.1 Gamma Slamming 4.2 Garbage Mattes 4.2.1 Pre-matting 4.2.2 Post-matting 4.3 Filtering the Matte 4.3.1 Noise Suppression with a Median Filter 4.3.2 Softer Edges 4.3.3 Controlling the Blur Operation 4.3.3.1 The Blur Radius 4.3.3.2 The Blur Percentage 4.3.3.3 Masking the Blur 4.4 Adjusting the Matte Size 4.4.1 Eroding a Matte with Blur and Scale 4.4.2 Dilating a Matte with Blur and Scale 4.4.3 Blurring Out 4.4.4 Sculpting Edges 4.5 Edge Masks Chapter 5 - Spill Suppression 5.1 Sources of Spill 5.2 The Despill Operation 5.3 Despill Algorithms 5.3.1 Green Limited by Red 5.3.1.1 Implementing the Algorithm 5.3.1.2 The Spillmap 5.3.2 Green Limited by the Average of Red and Blue 5.3.3 An Adjustable Despill 5.3.4 What About Blue Spill? 5.3.5 Refining the Despill 5.3.5.1 Channel shifting 5.3.5.2 Spillmap Scaling 5.3.5.3 Mixing Despills 5.3.5.4 Matting Despills Together 5.4 The Unspill Operation 5.4.1 How to Set It Up 5.4.2 Grading to the Backing Color 5.5 Despill Artifacts 5.5.1 Finding the Artifacts 5.5.2 Hue Shifts 5.5.3 Dark Edges 5.5.4 Fixing Despill Artifacts 5.6 Edge Grading 5.7 Edge Extension Chapter 6 - the Composite 6.1 Premultiply vs. Unpremultiply 6.1.1 Premultiply 6.1.2 Unpremultiply 6.1.3 The Double Premultiply 6.2 The Composite 6.2.1 The Over Composite 6.2.2 The KeyMix Composite 6.2.3 The AddMix Composite 6.2.3.1 How It Works 6.2.3.2 How to Build It 6.2.3.3 How to Use It 6.2.4 The Processed Foreground Method 6.2.4.1 The Workflow 6.2.4.2 What to Watch Out For 6.3 Compositing With a Keyer 6.3.1 Soft Comp/Hard Comp 6.3.2 "Cut and Paste" Keyer Composit