Conclusion

Keylight is a great tool, and tips in this chapter should help you get the results you're after. It's not the only option, of course. Primatte Keyer is just as powerful, with a completely different methodology, but you must purchase it separately. (The book's CD-ROM includes a demo if you want to check it out.)

The other potential candidate for pulling a professional blue-screen or green-screen key is Color Difference Key, which like Keylight is available as part of After Effects Professional. It uses an old and straightforward method of comparing the primary color being keyed (blue or green) against the other two color channels and using whichever channel offers the greatest difference to create the matte. This is similar to how optical keyers operate, although they do it photochemically, and how mattes were created in the earliest days of digital compositingsay, on Terminator 2. If you want to try it, follow the directions under "Applying the Color Difference Key" in the online Effects Help.

The next chapter offers assistance for situations where keying can't do the job, or can't do everything, and rotoscoping is necessary.