Adobe After Effects CS4 - Manual (Page 531)

525 USING AFTER EFFECTS CS4
Effects and animation presets
Last updated 12/21/2009
Several factors can affect the apparent color of the grain that these effects generate, including the following:
• The color value of the underlying pixel in the source image.
• The Saturation value of the noise.
• The Tint Color and Tint Amount values, if you have modified these settings from the defaults.
• The Blending Mode value in the Application controls group.
• The amount of noise applied, if any, to each channel individually using the Channel Intensities controls group.
Using the Color controls group in the Effect Controls panel, you can adjust any of the following:
Monochromatic Gives the added noise a single tint. By default, the tones are black and white, but you can change the
Tint Color to make it a gradient of any color. (The Saturation and Channel Intensities controls aren’t available if
Monochromatic is selected.)
Tint Amount Controls the depth and intensity of the color shift.
Tint Color Controls the color the added noise shifts toward.
Saturation Controls the amount and vividness of the color.
The Blending Mode in the Application controls determines how the color value of the generated noise combines with
the color value of the underlying source layer at each pixel:
Film Makes the generated grain appear embedded in the image. This mode affects darker colors more than lighter
ones, just as the grain in a film negative appears.
Multiply Multiplies the color values of the noise and the source. However, the result may be either lighter or darker
than the original, because the noise may have either a positive or negative value.
Add Combines the color values of the pixel in the source with the noise. However, the result isn’t always lighter than
the original because the noise created by grain effects can have either a positive or negative value.
Screen Multiplies the inverse brightness values of the noise and the source. The effect is like printing from a multiple
exposure on a negative. The result is always brighter than the original.
Overlay Combines the behavior of Film and Multiply: Both shadows and highlights get less grain, while midtones get
a full application of grain.
Add Grain effect
The Add Grain effect generates new noise from nothing and does not take samples from existing noise. Instead,
parameters and presets for different types of film can be used to synthesize many different types of noise or grain. You
can modify virtually every characteristic of this noise, control its color, apply it to the image in several ways, even
animate it or apply it selectively to only a part of your image.
This effect works with 8-bpc and 16-bpc color.
Original (left), and with effect applied (right)