Manual

830 Part IX Effects
Color Correction in Final Cut Express HD
With Final Cut Express HD, you have professional color correction tools at your disposal.
Controls that allow automatic adjustments of blacks and whites give even the beginner
a basic starting point from which to proceed. With patience and practice, you can learn
to work with these tools to achieve sophisticated color correction right on your
desktop. With a fast enough computer or a third-party capture card with real-time
processing, Final Cut Express HD color correction filters can even operate in real time,
eliminating the need to render every color-corrected clip.
Measuring and Evaluating Video
Before you can effectively perform color correction using the Final Cut Express HD color
correction features, you need to understand the basics of what makes up the image of
a video clip.
A video clip’s image can be divided into two components, luma (luminance) and
chroma (chrominance). Together, these two components make up the picture that you
see when you play back your video. As you begin to learn how to use
Final Cut Express HD scopes and color correction filters together to manipulate the look
of your clips, it is important to understand exactly what these components are.
Luma (Luminance)
Luma (also referred to as luminance) describes the image intensity of a video clip, from
absolute black, through the distribution of gray tones, all the way up to the brightest
white. Luma is completely separate from the color of your clip. In fact, if you viewed the
luma of a video clip by itself, you would see a grayscale image completely devoid of color.
Luma is measured by Final Cut Express HD as a digital percentage from 0 to 100, where
0 represents absolute black and 100 represents absolute white. Final Cut Express HD
also allows you to see super-white levels (levels from 101 to 109 percent) if they exist in
your clip. While super-white video levels are not considered to be broadcast safe, many
consumer camcorders record video at these levels anyway.
Note: In analog video, luma is measured in IRE. On the IRE scale, NTSC black is 7.5 IRE,
but the level of black in PAL or NTSC in Japan is 0. These IRE measurements are
irrelevant in Final Cut Express HD because it deals only with the digital signal that exists
in your computer as a straight percentage from 0 to 100 for NTSC and PAL.
Black
0% luminance
100%
109%
White
Superwhite