Colors and Levels
After you get beyond the formatting and resolution issues, the next thing to educate your graphic designer in on is color. Video is much more forgiving than the Web. Although you are not restricted to just the limited palette of Web-safe colors, there are a number of guidelines that need to be considered. Most of these rules apply to broadcasting video, but if you are educating your graphic designer to create for video, it's good practice that he do it right, even if the final content will not broadcast by the networks or cable television. I guess you can feel free to disregard these rules if you are producing video for you own personal use, but keep in mind that they have been established because images created within these guidelines look best on television.
The rules relating to color and levels when developing video to be played over the Internet are similar to broadcast television, but seem to be slightly more flexible and forgiving. In regard to color, be aware that oversaturated colors tend to appear to bleed. That means you will see the colors within an image smear or run outside the boundaries of the actual image. If you are developing graphics professionally (again, especially for broadcast) talk to your video editor and have him test your designs on a Vectorscope (a measurement device used to test the saturation and hue/phase of the video signal).
Another important aspect is the actual video level. Without turning this into a week-long lecture on broadcast video levels, I will highlight some of the key aspects to be aware of when developing images for video. The two major aspects are the black levels (or the darkest portions of your image) and the white levels (or brightest portions of your image). Again, your video editor can check your images through a similar measurement-testing device known as a Waveform Monitor. In general, this unit allows the editor to monitor when his video signal is within legal broadcasting white and black levels.
Typically, creating a pure black file in Photoshop (or another design application) set at 0,0,0 will produce a black level that is too low for broadcasting purposes. The designer needs to bring up those levels a bit. On the bright side, creating a pure white file of 255, 255, 255 would exceed the legal broadcasting brightness level. Instead, what appears to be safe "white" on video is actually a very light shade of gray from a design perspective, say somewhere around 235, 235, 235.
With multimedia video, the image quality may need to be adjusted. Typically, PCs display images (including video) darker than what appears on Macs. Depending on your audience, you may wish to adjust the brightness and levels of your overall video output, but I would still recommend following the guidelines established for designing and developing for broadcast video. Once you create and export a multimedia file (such as a QuickTime, AVI, or MPEG), you can always run your file through a third-party software application, in which you can control and adjust the brightness and contract of your overall video signal. One of the best applications on the market is Discreet's Cleaner 5.0.