Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 470

How to apply the noise to the alpha channel:
Original Alpha
• Produces equal amounts of noise in the transparent and opaque areas of the clip.
Add
• Produces noise in the opaque areas only.
Clamp
•
Increases the amount of noise proportionate to the level of opacity and produces no noise in 100% trans-
Scale
parent areas.
• Produces noise only in partially transparent areas, such as the edge of the alpha channel.
Edges
How the effect remaps values that fall outside the grayscale range of 0-255:
Overflow
•
Values above 255 are mapped to 255. Values below 0 are mapped to 0.
Clip
•
Values above 255 or below 0 are reflected back into the 0-255 range. For example, a value of 258
Wrap Back
(255+3) is reflected to 252 (255-3), and a value of -3 is reflected to 3.
•
Values above 255 and below 0 are wrapped back around into the 0-255 range. For example, a value of 258
Wrap
wraps around to 2, a value of 256 wraps around to 0, and a value of -3 wraps around to 253.
An input value to the random number generator for the noise. This control is active only if you choose
Random Seed
Uniform Random or Squared Random.
To produce flashing noise, animate the Random Seed control. To create smoothly animated noise, animate the Noise
Phase value.
Specifies the placement of noise. This control is active only if you choose Uniform Animation or
Noise Phase
Squared Animation.
Noise Options (Animation)
•
Produces a cycle of noise that plays through once in the specified amount of time.
Cycle Noise
• Specifies the numbers of revolutions of the Noise Phase that the noise cycles through before it repeats
Cycle
(available only when Cycle Noise is selected).
Alter the timing of the Noise Phase keyframes to adjust the speed of the Noise Phase cycles.
To save time animating the Noise Phase value, use the Cycle Noise option to create a seamless noise loop. Then,
render the layer, and reimport it as a new source footage item.
Noise HLS effect and Noise HLS Auto effect
The Noise HLS and Noise HLS Auto effects add noise to the hue, lightness, and saturation components of an image.
The noise generated by the Noise HLS Auto effect is automatically animated noise; you choose the speed of the
animation. To animate the Noise HLS effect, you must use keyframes or expressions. Controls for these effects are
the same except for the Noise Phase or Noise Animation Speed control, which controls noise animation.
These effects work with 8-bpc color.
How noise is animated.
AFTER EFFECTS CS3 464
User Guide