There are different ways of using Flash for television. However, due to the nature of the television display, they all share a variety of common development issues. No matter how you produce Flash for television, you are certain to run into specific problems and limitations.
Many of these limitations today stem from the fact that standard TV technology generally needs to be backward compatible. In other words, today's consumer NTSC color television is still pretty much determined by the lowest common denominator the 1950's black-and-white TV set, which still has to be able to generate a proper display from modern-day color TV transmissions.
Modern computer screens on the other hand aren't restricted to 525 or 625 horizontal lines or interlaced images. Monitors have a much higher definition and do generally better in displaying colors. Therefore, graphics created on a computer have to be adjusted for the poorer display quality of TV sets.
Fonts and Readability
Because television resolution is low and viewers are further from the screen, it's crucial to use easy-to-read fonts at a large point size. Fonts such as Helvetica, Arial, or other sans serif fonts are the most readable on televisions. Standard font sizes for readability are 18pt and above. Fonts inside of Flash should probably be set to 24pt and higher because Flash renders fonts a bit "fuzzier" than HTML and therefore are more difficult to read.
Graphics techniques such as drop shadows can be used to set off titles from a background. To distinguish text from background, the color contrast between them will have to bigger than on computer monitors. Larger fonts should be anti-aliased to avoid interlacing problems such as flicker.
Because text is difficult to read on television monitors it's important that text stays on the screen long enough for someone to read it. For the viewer's sake, err on the side of text being on the screen too long.
Consumer TV sets do not display the full range of NTSC's 640x480 or PAL's 720x486 resolution formats. Due to an effect called overscanning, the average consumer TV loses a portion of the image. Therefore, crucial content should not be placed too close to the edges of your image. The safe area for action should be considered 10% smaller for action and 20% smaller for titles. If you are new to TV graphics, you should create safe area frames for your design in Flash (see Figure 11.1). They'll remind you to keep crucial content inside.
Figure 11.1. Creating title and action safe frames for your Flash movie allow content to be created that will be seen by viewers.