Digital Video - March 2008 - (Page 28)

KEY THOUGHTS ON CHROMA KEY GREENSCREEN: SALVATION FOR THE CREATIVE VIDEOMAKER. BY SCOTT BILLUPS The following is an excerpt from the recently released book “Digital Moviemaking 3.0” (Michael Wiese Productions, 2008). While it is specific to working with chroma key, the book itself offers a wealth of digital production and post advice. C hroma key is your friend because it releases you from the shackles of reality. There is no other technique that can so drastically increase the scope of your show or so favorably impact the bottom line. Even projects that would not be considered as visual-effects productions can benefit greatly from a number of different uses. One of the most common uses is with regard to pickups. By now it should be de rigeur for every production crew to shoot a clean plate or two of a set or location before they wrap out. When it comes time to shoot that obligatory pickup or missed line, a little pop-up greenscreen can save thousands of dollars. Although the topic of chroma key is encumbered with mismatched bits of outdated information, the practical job of shooting good elements are really quite simple: Cloth is better than paper, and paint is better than cloth. Blue for film, green for digital. Blonds on blue, everyone else on green. Don’t use a bigger screen than you need. Costume color conflicts must be taken seriously. Pop-up screens can handle most of your needs. A little “straw” gel in the backlight works wonders. Never let a tracking mark cross the face or hair. Turn the camera’s detail circuit off. Shoot a progressive image whenever possible. Get the actor as far away from the screen as possible. Match the actor’s lighting to the back-plate. Scott Billups in action behind the camera. Lighting chroma key was once a difficult task, but the newer “digital” colors and the greatly evolved 3-space chroma key software open this powerful process up to anyone with a laptop. Digital green requires far less light than older chroma key green, and it lights more evenly. In many cases, available light is all you’ll need to pull a great key. As one of my favorite gaffers puts it, “a thermonuclear fusion source with a water vapor diffusion system is the perfect system for lighting chroma key” (Cloudy day). 28 dv march 2008 3-D keyers are far more forgiving than the older 2-D systems. You still need to get the screen rather flat, but the increased dynamic range of newer keyers is far more forgiving. For studio work, you’d be hard pressed to beat Space Lights for their soft volume and even spread or a couple Kino Flo banks for a more focused spread. Chroma key software is a long topic; lots of egos, with lots of opinions. Cheapest and easiest chroma key system is Apple’s iMovie and a copy of GeeThree’s Slick Effects. At $50, you’ll need to spend a whole lot more to get to the next usable keyer. Top-of-the-line keyers in daily use at the Billups household include Red Giant’s Primatte, the Foundry’s Keylight and zMatte by Digital Film Tools. Between my wife and I, we pull well over 3,000 mattes a year for movies, commercials and HD TV shows. My wife is an Inferno operator and loves the Autodesk keyers. Whenever I run into a shot that I just can’t get to pull correctly, I give it to her. Part of it is that she’s just more talented than I am, and part of it is that the Inferno/Combustion keyer is great. Tim Sassoon is a Cinemagician. His Santa Monica-based visual effects company blends science and craft to create high-end visual effects for everything from commercials to IMAX. His take: “The only thing about keying is color correcting the image to www.dv.com http://www.dv.com

Table of Contents Feed for the Digital Edition of Digital Video - March 2008

Digital Video - March 2008 Contents DV Update Q&A Fest Circuit Instant Expert LP-Micro Light Fusion F2 Drive PPFP-3N Bag Ego Digital Imaging Light KE-79CC Boom & Fuzzy Close-Up: Honoring George Spiro Dibie, ASC Food Fight Key Thoughts on Chroma key DV101 Dynamic Duos First Look: A Big Serve Cameras & Courtrooms Ad Index Production Diary

Digital Video - March 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.