VFX Keying: Master Course

Take a deep dive into keying for visual effects in NUKE. Learn about green-screen, blue-screen, luma, and saturation keys; spill suppression; color correction; and edge refinement.

Introduction

• Welcome
• Exercise files

1. Keying Workflows

• A look at different keying workflows
• Creating an uber key
• The nature of grain and noise
• Green-screen vs. blue-screen keying
• Which keyer is best?

2. Pre-Processing the Green Screen

• Step 1: Analyze the clip
• How to manage grain and noise
• Pre-processing the clip for the keyer
• Screen-correction workflow
• Tips on adjusting the IBKColor node
• How the IBKColor assist works
• Building a clean plate from a clip
• Building a clean plate without an IBK node
• Working with a real clean plate
• Retaining shadows with screen corrections
• Stack IBKColor nodes for cleaner clean plates
• Good (and bad) tracking markers
• Tracking marker removal techniques
• Removing tracking markers with screen correction

3. Other Types of Keys

• Unleashing the power of your luma keys
• How to make even more powerful luma keys
• Keying on hue
• Keying on saturation
• Discovering NUKE's hidden chroma keyer
• Keying with just one channel
• How to create a color difference key
• How to create a texture key

4. Building the Uber Key

• How to cut and paste keys together
• Which math operation to use and when
• Assisting the keyer with additional keys
• Using garbage mattes to save time
• Creating core mattes for solid keys

5. Spill Suppression

• What is spill?
• How spill suppression works
• Spill suppression with the Hue Correct node
• Spill suppression with gizmos
• How to prevent despill artifacts
• How to fix despill artifacts
• Adjusting the spill luminance and color
• Steve Wright's adaptive despill

6. Compositing Techniques

• The classic Premultiply > Merge over
• Improving edges with an AddMix comp
• How to do a soft comp/hard comp
• The processed foreground technique
• Adding edge detail with an additive keyer

7. Color Correcting

• Effects of color correction on pixels and pictures
• The Grade node vs. the ColorCorrect node
• Premultiply and unpremultiply
• How to match grade two clips
• Color match keyed layers workflow

8. Workflow Examples

• Compositing keyer outputs
• The basic uber key composite
• Soft key/hard key with luminance adjusted despill
• Uber key with split soft key and split despill
• Uber key with the additive keyer
• Screen correction with adaptive despill
• Screen correction with a processed background

9. Sweetening the Comp

• How to apply light wrap to your comp
• When to use edge blending
• Adding interactive lighting
• Animating the interactive lighting
• Easy ways to synthesize shadows
• How to QA your comp

10. Fixing Edge Problems

• Sculpting your key edges
• Recoloring the RGB edges
• Replacing discolored edges: Theory
• Replacing discolored edges: Practice

11. Special Keying Solutions

• How to add more hair detail
• The special case of keying blond hair
• Keying for more semitransparency
• Techniques for better motion blur
• How to retain all of the depth of field
• Special keying techniques for smoke
• Extra special keying techniques for fire
• How to key a cloud out of the sky
• Keying reflections off of glass techniques
• How to cope with bad video

12. Appendix: Keyer Tutorials

• About the Keyer Tutorials appendix
• KEYLIGHT: Setting up a basic composite
• KEYLIGHT: Masking, fine-tuning, and spill suppression
• KEYLIGHT: Viewing status and multipass keying
• Primatte: Basic keying and spill suppression
• Primatte: Matte refinement and edge detail
• Primatte: Auto-Compute and advanced spill suppression
• Primatte: New features in Primatte V
• IBK keyer: Keying and compositing
• Ultimatte: Basic setup
• Ultimatte: Overall workflow
• Ultimatte: Matte tools and shadows
• Ultimatte: Spill suppression