Adobe 65008009 - After Effects CS4 Technical Paper page 28

box and assign the HDTV (Rec. 709) 16-235 profile to your footage in the Interpret Footage
dialog box. Color values will be preserved because the profile assigned to your footage in the
Interpret Footage dialog box is the same as the profile set for the project's working space.
However, 16 RGB will be mapped to the darkest black on you monitor and 235 mapped to the
lightest white on your monitor, creating the impression of a full-range image on your moni-
tor. Keep in mind that some blending modes and effects expect black to be at a value of 0.
Unexpected results may appear when black is not set at 0.
Note: You can maintain footage values by using the full-range HDTV (Rec. 709) profile for inter-
preting footage, for the project working space, and for the output profile. However, if your footage
is within the limited range of 16-235 and you use the HDTV (Rec. 709) profile as the project
working space, then images will appear to have less dynamic range and contrast.
3 Compress luma levels on output:
Choose one of the "16-235" profiles in the Color Management tab of the Output Module
Settings dialog box. These profiles will insure that the luma levels in your rendered file will be
within the 16-235 range. If your project working space was full-range (0-255), then color values
will be compressed into the limited 16-235 range on output.
If your project working space was one of the "16-235" profiles, there will be no luminance com-
pression on output, but the final output will be within the limited 16-235 range.
RGB=255
RGB=0
RGB
(After Effects
project)
Figure 3 — Luma compression for video output
Y=255
overbrights
Y=235
Y=16
super black
Y=0
YCbCr
Color management workflow in Adobe After Effects CS4 28