Maximum RGB White Level Settings
When you add graphics or generator clips created in the RGB color space (for example,
imported graphics files or generator clips created with generators such as the Text
generator), the “Process Maximum White as” pop-up menu determines whether the
maximum white value of these clips should be 100 percent or 109 percent. Use this
pop-up menu to make sure the white levels of your RGB footage match those of your
video. Because most still images and generators use the RGB color space and
most video footage is recorded in the Y´C
color space, it is important to check this
pop-up menu whenever you add graphics to your sequence.
and RGB video systems assign maximum white levels to different digital codes,
as shown here with an 8-bit video example.
A 100 percent
white value in Y´C
video is the legal limit for broadcast television and
generally corresponds to the analog broadcast legal limit of 100 IRE. However,
camcorders and decks allow white levels above this level (up to 109 percent) to avoid
clipping occasional highlights. For example, even if you set your camcorder exposure
so that it appears no level is above 100 percent, highlights from shiny objects can go
beyond 100 percent. Having the extra headroom from 100 percent
to 109 percent
allows you to capture these highlights without losing details in the white.
If you are creating video for broadcast, you need to make sure that any Y´C
your sequence are reduced to 100 percent
(8-bit 235, or “white”). In this case, choosing
the White option from the “Process Maximum White as” pop-up menu maps RGB white
(255) values from imported still images to 100 percent
white (235) in the Y´C
space. This means that your RGB graphics will have a maximum white level of 100
color space, which is the broadcast-legal limit.
RGB 8-bit value
Rendering and Video Processing Settings
If you aren’t concerned about broadcast-legal limits and you want your imported RGB
graphics to match Y´C
white levels that are above 100 percent, you should choose
the Super-White option from the “Process Maximum White as” pop-up menu. In this
case, RGB white values of 255 are mapped to Y´C
values of 254 (109 percent). Keep
in mind that any white levels in your RGB graphics will not be broadcast-legal.