Join Steve Wright for an in-depth discussion in this video How to create a color difference key, part of VFX Keying: Master Course.
- [Teacher] In the previous video,…we saw strategies for pulling a key from a single channel.…Here, we'll kick it up a notch…and make more discriminating keys…by using the difference between two-color channels…such as green minus red, for example.…This is a surprisingly powerful technique…that can produce some very nice keys…with just a few minutes of work.…Now this is a basic color difference key setup.…The idea is, you can just walk through here…and see all the different channel arithmetic operations.…
The idea is we always start with a de-noise node…to get rid of the noise to make for cleaner keys.…These are just shuffle nodes where I have shuffled…the entire red channel into this data stream.…So I now have a red image, a green image, and a blue image…so that I can use merge nodes instead of the channel merge.…This just makes it easier to follow the process.…At the end, we'll redo it with channel merge nodes.…So we have all possible combinations.…
Here is what red minus blue looks like, red minus green,…green minus red, green minus blue,…
Note: This course was created by Steve Wright, author of the seminal book, Digital Compositing for Film and Video. We are proud to host this course in our library.
- Creating an uber key
- Keying green-screen vs. blue-screen footage
- Preprocessing footage
- Building a clean plate
- Making luma keys
- Keying on hue and saturation
- Pasting keys together
- Grain management
- Saving time with garbage mattes
- Using spill suppression
- Improving edges
- Color correcting keys
- Sweetening the comp
- Alternative compositing workflows
- Fixing edge problems
- Using KEYLIGHT, Primatte, Ultimatte, and other tools
Skill Level Intermediate
Compositing a Sci-Fi Force Field in NUKEwith Steve Wright2h 12m Intermediate
Compositing an Alien Portal in NUKEwith Steve Wright2h 20m Intermediate
1. Keying Workflows
2. Pre-Processing the Green Screen
3. Other Types of Keys
4. Building the Uber Key
5. Spill Suppression
6. Compositing Techniques
7. Color Correcting
How to match grade two clips4m 15s
8. Workflow Examples
9. Sweetening the Comp
10. Fixing Edge Problems
11. Special Keying Solutions
12. Appendix: Keyer Tutorials
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