Using Chroma Key Walls

Pic83Chroma key walls are a great way to expand your school news sets without building an expensive new addition to the existing studio.

Fortunately, chroma key technology is becoming more and more readily available in even consumer-grade video production tools.

Obviously the first thing you'll need to have is a chroma key wall. Chroma key walls can technically be any color, but bright blue and green are the most common. Of these, green has tended to become preferred over the past few years since you're much less likely to run into someone wearing a fluorescent green piece of clothing!

There are companies that make fabric chroma key walls that can be hung from thePic81 wall as well as pop-up ones. The pop-up ones tend to be smaller but are more than adequate for many productions. Another option is to paint a wall in your studio area. While pre-made paint is available in chroma key blue and green, you can also have it mixed up at your local paint or home improvement store. Just look for the most garish shade of bright green they offer in the color chip rack. If it still doesn't look quite right, the worker can usually add some additional pigments to get it where you need it. If you do buy paint, be sure to buy an matte or egg shell type not a glossy since this will make things hard for you in production.

The key to good chroma keying, however, is even lighting. You need to make sure that the chroma key wall, whatever format you chose, is lit evenly with no "hot" spots or darker areas. These can confuse the software, though depending on how good your software is this may not be as much of a problem as you think.

Pic82In general it's best to have your talent stand a few feet in front of the key wall, but experiment with what works best in your setup. One of the other issues that chroma key can bring is the "glow" around talent. This can usually be fixed with lighting adjusts. Or, if your software allows it, you may be able to adjust it to make it work better.

Now that you have a key wall, what to put in it?

You can make simple backgrounds on a photo editing program or buy from a variety of companies that make pre-designed ones.

ChromaVault (www.chromavault.com) works frequently with schools and offers low-cost Pic84chroma key wall graphics in a variety of topics including news, sports and all-purpose backgrounds as well as virtual sets. The images come in a format that works in virtually all chroma keying systems as well as 16:9 and 4:3. They are created at a high-quality level that allows you to crop and "zoom" in on certain areas.

Most ChromaVault products start at $20 each but frequent sales lower the price to as low as $4.99. In additiona to chroma key backgrounds, ChromaVault also offers a ready-to-go graphics package featuring lower thirds, over the shoulder and other templates that are perfect for school news programs. A matching OTS package is geared specifically toward schools.

Chroma keying can be used for as little or as much of your programming as you want. You can even do the entire school announcements from in front of a key wall, changing out the graphics behind the talent to match what's being talked about. Or, you could use it for specialized parts of the newscast. The format works partcularly well with things such as on-air trivia questions, polls or "words of the week" type features since your talent can point to the various choices and correct answers.

Of course key walls can also be used for fun! You can instantly transport your students to a tropical beach or ski slope with the click of the mouse. Another option is to create fun effects by having students wear clothing that matches the key wall color to make parts of their body disappear. This is particuarly fun to do on Halloween and April Fools day.

Richard Day is the founder of ChromaVault (www.chromavault.com), a Web site that sells low-cost chroma key backgrounds for school and other video productions.