Adobe Premiere Pro CS4 - Manual (Page 353)

347 USING ADOBE PREMIERE PRO CS4
Effects and transitions
Last updated 11/6/2011
Calculations effect
The Calculations effect combines the channels of one clip with the channels of another clip.
Original images (left and center), and with effect applied (right)
Input Channel The channel to extract and use as input to the blending operation. RGBA displays all channels
normally. Gray converts all color channel values for a pixel to the luminance value of the original pixel. Red, Green, or
Blue converts all color channel values for a pixel to the value of the selected color channel for the original pixel. Alpha
converts all channels to the value of the alpha channel for the original pixel. For a video tutorial on using the
Calculations effect and the Ramp effect, see
Coloring A Washed-out Sky With A Gradient In Premiere Pro CS by Jeff
Schell on his Digital Media Net blog.
Invert Input Inverts the clip before the effect extracts the specified channel information.
Second Layer The video track with which Calculations blends the original clip.
Second Layer Channel The channel to be blended with the input channels.
Second Layer Opacity The opacity of the second video track. Set to 0% for the second video track to have no influence
on the output.
Invert Second Layer Inverts the second video track before the effect extracts the specified channel information.
Stretch Second Layer To Fit Stretches the second video track to the dimensions of the original clip before blending.
Deselect this option to center the second video track on the original clip.
Preserve Transparency Ensures that the original layer’s alpha channel isn’t modified.
Compound Arithmetic effect
The Compound Arithmetic effect mathematically combines the clip to which it’s applied with a control layer. The
Compound Arithmetic effect is intended only to provide compatibility with projects created in earlier versions of After
Effects that use the Compound Arithmetic effect.
Second Source Layer Specifies the video track to use with the current clip in the given operation.
Operator Specifies the operation to perform between the two clips.
Operate On Channels Specifies the channels to which the effect is applied.
Overflow Behavior Specifies how pixel values that exceed the allowed range are treated:
• Clip Indicates that the values are limited to the allowed range.
• Wrap Indicates that values exceeding the allowed range wrap around from full on to full off, and vice versa.
• Scale Indicates that the maximum and minimum values are calculated and the results are stretched down from that
full range to the range of allowable values.
Stretch Second Source To Fit Scales the second clip to match the size (width and height) of the current clip. If this option
is deselected, the second clip is placed at its source’s current size, aligned with the upper left corner of the source clip.