Adobe 65021048 User Manual page 307

ADOBE PREMIERE PRO CS3 301
User Guide
Posterize effect
The Posterize effect lets you specify the number of tonal levels (or brightness values) for each channel in an image.
The Posterize effect then maps pixels to the closest matching level. For example, choosing two tonal levels in an RGB
image gives you two tones for red, two tones for green, and two tones for blue. Values range from 2 to 255.
The number of tonal levels for each channel.
Level
ProcAmp effect
(High bit-depth) The ProcAmp effect emulates the processing amplifier found on standard video equipment. This
effect adjusts the brightness, contrast, hue, saturation, and split percent of a clip's image.
Shadow/Highlight effect
The Shadow/Highlight effect brightens shadowed subjects in an image and reduces the highlights in an image. This
effect doesn't darken or lighten an entire image; it adjusts the shadows and highlights independently, based on the
surrounding pixels. You can also adjust the overall contrast of an image. The default settings are for fixing images
with backlighting problems.
If this option is selected, the Shadow Amount and Highlight Amount values are ignored, and
Auto Amounts
automatically determined amounts are used that are appropriate for lightening and restoring detail to the shadows.
Selecting this option also activates the Temporal Smoothing control.
The amount to lighten shadows in the image. This control is active only if you deselect Auto
Shadow Amount
Amounts.
The amount to darken highlights in the image. This control is active only if you deselect Auto
Highlight Amount
Amounts.
The range of adjacent frames, in seconds, analyzed to determine the amount of correction
Temporal Smoothing
needed for each frame, relative to its surrounding frames. If Temporal Smoothing is 0, each frame is analyzed
independently, without regard for surrounding frames. Temporal Smoothing can result in smoother looking
corrections over time.
If this option is selected, frames beyond a scene change are ignored when surrounding frames are
Scene Detect
analyzed for temporal smoothing.
The effect's transparency. The result of the effect is blended with the original image, with the
Blend With Original
effect result composited on top. The higher you set this value, the less the effect affects the clip. For example, if you
set this value to 100%, the effect has no visible result on the clip; if you set this value to 0%, the original image doesn't
show through.
Expand the More Options category to reveal the following controls:
The range of adjustable tones in the shadows and highlights.
Shadow Tonal Width and Highlight Tonal Width
Lower values restrict the adjustable range to only the darkest and lightest regions, respectively. Higher values
expand the adjustable range. These controls are useful for isolating regions to adjust. For example, to lighten a dark
area without affecting the midtones, set a low Shadow Tonal Width value so that when you adjust the Shadow
Amount, you are lightening only the darkest areas of an image. Specifying a value that is too large for a given image
might introduce halos around strong dark to light edges. The default settings attempt to reduce these artifacts. They
can be further reduced by decreasing these values.
The radius (in pixels) of the area around a pixel that the effect uses to
Shadow Radius and Highlight Radius
determine whether the pixel resides in a shadow or a highlight. Generally, this value should roughly equal the size
of the subject of interest in your image.
April 1, 2008