Adobe After Effects CS4 - Manual (Page 543)

537 USING AFTER EFFECTS CS4
Effects and animation presets
Last updated 12/21/2009
Sharpen an image with Unsharp Mask controls
The Remove Grain effect contains Unsharp Mask controls, which increase the contrast of edges and fine details to help
restore some of the sharpness that may have been lost during the grain reduction process.
❖ Do any of the following:
• Increase the Unsharp Mask controls Amount value to obtain acceptable sharpening without generating undesirable
artifacts or bringing back too much grain.
• Increase the Threshold value to remove any unwanted artifacts that resulted from the sharpening.
• Adjust the Radius to change the area over which Unsharp Mask finds details.
• Adjust the Noise Reduction value until the image begins to lose sharpness; then decrease the value a little, and then
apply the Unsharp Mask controls to sharpen the image.
Turbulent Noise effect
The Turbulent Noise effect uses Perlin noise to create grayscale noise that you can use for organic-looking
backgrounds, displacement maps, and textures, or to simulate things like clouds, fire, lava, steam, flowing water, or
vapor.
The Turbulent Noise effect is essentially a modern, higher-performance implementation of the Fractal Noise effect.
The Turbulent Noise effect takes less time to render, and it’s easier to use for creating smooth animations. The
Turbulent Noise effect also more accurately models turbulent systems, with smaller noise features moving more
quickly than larger noise features. The primary reason to use the Fractal Noise effect instead of the Turbulent Noise
effect is for the creation of looping animations, since the Turbulent Noise effect doesn’t have Cycle controls.
Note: Because the controls for the two effects are nearly identical, you can use most instructions and tutorials created for
the Fractal Noise effect to instead guide your use of the Turbulent Noise effect. (See “
Fractal Noise effect ” on page 527.)
The Evolution controls create subtle changes in the shape of the noise. Animating these controls results in smooth
changes of the noise over time, creating results that resemble, for example, passing clouds or flowing water.
This effect works with 8-bpc, 16-bpc, and 32-bpc color.
Controls
Fractal Type The fractal noise is created by generating a grid of random numbers for each noise layer. The Complexity
setting specifies the number of noise layers. The Fractal Type setting determines the characteristics of this grid.
Noise Type The type of interpolation to use between the random values in the noise grid.
Invert Inverts the noise. Black areas become white, and white areas become black.
Contrast The default value is 100. Higher values create larger, more sharply defined areas of black and white in the
noise, generally revealing less subtle detail. Lower values result in more areas of gray, softening or muting the noise.
Overflow Remaps color values that fall outside the range of 0–1.0, using one of the following options:
• Clip Remaps values so that any value above 1.0 is displayed as pure white, and any value below 0 is displayed as
pure black. The Contrast value influences how much of the image falls outside this range. Higher values result in a
mostly black and/or white image with less gray area. Therefore, higher contrast settings display less subtle detail. When
used as a luma matte, the layer has sharper, better-defined areas of transparency.
• Soft Clamp Remaps values on an infinite curve so that all values stay in the range. This option reduces contrast and
makes noise appear gray with few areas of pure black or pure white. When used as a luma matte, the layer contains
subtle areas of transparency.