NOTE | Graphic Math Anxiety, Part IIWhat Color Is White?
Wouldn't it be nice if… computers and video used the same white and black levels? Well, they don't. When you hear terms like "8-bit video" and "10-bit video," the bits refer to the number of levels between maximum black and maximum white. Eight-bit video has 256 discrete levels, and 10-bit video has 1,024 levels.
This means pure black on the computer has an RGB value of 0,0,0, and pure white on the computer has an RGB value of 255, 255, and 255.
The problem is that video doesn't have that great a range. In 8-bit video, video black in the U.S. is only 16 (as measured on the RGB scale) and video white is 235. To complicate matters, video is measured in IRE, where 7.5 IRE equals video black and 100 IRE equals video white. The reason you need to care is that you can create graphics on your computer that are too white. When they are broadcast, they visually distort and make the audio buzz. Not good. If you are creating professional-level video, this results in your tapes getting rejected for poor technical quality. There is some good news, however. First, create all your graphics with black set to 0. Your capture card or DV deck handles the conversion to the proper level of black automatically. [View full size image]
With white settings, it isn't so easy, though Final Cut adds a preference to help. Choose Sequence > Settings (or press Cmd+0) and click the Video Processing tab.
Here's the rule: if you are outputting to DV or DVD, set this pop-up to Super-White. If you are outputting to a professional SD format, such as Betacam, set this pop-up to White. What this menu tells Final Cut to do is "clamp," or automatically reduce, all imported graphics so that their white levels match the tape format to which you are recording. This setting affects only imported graphics, and not video, but, still, it's a great help. (You'll learn a way to clamp video white levels at the end of the next exercise.) |