Join Mark Christiansen for an in-depth discussion in this video Avoid compression: The enemy of mattes, part of After Effects Compositing: 4 Color Keying.
- When recording a green screen scene,…it's the recording format more than the camera or the lens…that matters although those do still matter a lot.…It's vital that the image be recorded…with as little noise and compression as possible,…and that rules out a lot of the most popular camera systems.…This appears to the naked eye…to be the same shot looping over and over,…and it is, with one subtle difference.…There are two versions of the same shot,…which appear the same to your naked eye,…but in fact one of them has no JPEG compression on it,…it's originally from the Blackmagic camera,…and the other one is 4:2:2 compressed to H.264,…similar to what you would get…from your typical Canon or Nikon DSLR,…so the lens optics are awesome in both cases,…there's lots of nice hair detail,…and you really only notice that…there's a problem when you go to key it.…
4:2:2 compression refers to the ratio…between luminance and chrominance.…With a 4444 image such as this one,…there's the same amount of data…assigned to luminance and chrominance.…
Author
Mark Christiansen
Released
12/6/2014Beginning with a brief explanation of the keying process, Mark takes you through the steps involved in creating a perfect green-screen key: generating a rough matte, eliminating color spill and matte lines, and refining problematic edges. He shows how to work with Keylight and Primatte—two indispensable keying tools in After Effects—and explains when to use one over the other. And for times when green screen won't work, he shows how to generate high-contrast mattes, or luma keys, based on the luminance data in your footage. Last, learn about compression and how to prep a shot for keying.
- What is color keying?
- Using garbage mattes
- Getting started with Keylight
- Understanding the Screen Color, Clip Black, and Clip White adjustments
- Eliminating spill with Advanced Spill Suppressor
- Using Key Cleaner to refine edges automatically
- Dividing a matte with holdout mattes
- Breaking down a complex color key
- Creating a luma key with Extract
- Setting up sky replacement
- Using Refine Soft Matte to improve edge detail
- Feathering edges with Channel Blur
- Knowing when to avoid green screen
- Prepping a shot for keying
Skill Level Intermediate
Duration
Views
Q: How do I locate the exercise files for chapter 5, 6, and 7 of this course?
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Introduction
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Welcome1m 46s
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Using the exercise files2m 23s
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1. Work with Keylight
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2. Manage Edges and Spill
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3. Divide a Matte for Best Results When Keying
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Add a holdout matte1m 38s
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4. Solve Problematic Edges
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5. Complex Color Keys and Primatte
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6. High-Contrast Mattes (When There Is No Green Screen)
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7. Prep for Success When Color Keying
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Prep a shot for keying3m 4s
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Video: Avoid compression: The enemy of mattes