Getting the Right Size
Size does matter when creating images for video. Like anything else these days with so many different formats on the market, there are a few variations to the numbers I'm going to give you, but you'll get the idea. Once again, check with a video editor to find out which format size he will be working in so you create your graphics in the proper aspect ratio and file size. Continuing with the example of dealing with NTSC standard definition, you are talking about working with an aspect ratio of approximately 4:3. That's four wide by three high. In pixels, the standard size is 720 pixels wide by 486 pixels high. If you look at your television (unless you have a HDTV wide-screen television, which is at a 16:9 ratio), it should look fairly rectangular, slightly wider than it is high. So when a graphic designer creates a full-screen graphic for NTSC broadcast television standards, the final size should be 720x486 pixels (or 10 inches by 6.75 inches).
As I've told you, each format and each system varies slightly. DV format is 720x480. Even if you are not creating a graphic to cover the full screen, you still need to work within those boundaries. To get a perspective on how large you need to create a file that will not be full screen, create an image in Photoshop at 720x486. On a new layer, create the image you intend to use for the video. Use the size of the image to give you an idea of how large your image will be and how much of the full video screen it will cover. One more reason to check with your video editor about which system he will be using is how each system works with files. For instance, Avid recommends creating images at 720x540 first. When you are finished, change the image size to 720x486. This will appear to squash your image or take things out of the correct perspective, but don't worry. When the file is imported into the Avid, the file is converted back into the proper perspective, making everything look the way it was supposed tono longer squashed.