ADOBE PREMIERE PRO 2.0
User Guide
342
Time effects
Echo effect
The Echo effect combines frames from many different times in a clip. It has a variety of uses, from a simple visual
echo to streaking and smearing effects. This effect is visible only when there is motion in the clip. By default, any
previously applied effects are ignored when you apply the Echo effect.
Echo effect: Original image (left), with low echo values (center), and with increased number of echoes (right)
The Echo effect has the following settings:
Echo Time
Specifies the time, in seconds, between echoes. Negative values create echoes from previous frames;
positive values create echoes from upcoming frames.
Number Of Echoes
Specifies the number of frames to combine for the Echo effect. For example, if two echoes are
specified, Echo will make a new image out of [current time], [current time + Echo Time], and [current time + 2 *
Echo Time].
Starting Intensity
Specifies the intensity, or brightness, of the starting frame in the echo sequence. For example, if
this is set to 1, the first frame is combined at its full intensity. If this is set to 0.5, the first frame is combined at half
intensity.
Decay
Specifies the ratio of intensities of subsequent echoes. For example, if the decay is set to 0.5, the first echo will
be half as bright as the Starting Intensity. The second echo will then be half that, or 0.25 times the Starting Intensity.
Echo Operator
Specifies the operations to be performed between echoes:
•
Add
Combines the echoes by adding their pixel values. If the starting intensity is too high, this mode can quickly
overload and produce streaks of white. Set the Starting Intensity to 1.0 per number of echoes and the Decay to 1.0 to
blend the echoes equally.
•
Maximum
Combines the echoes by taking the maximum pixel value from all the echoes.
•
Minimum
Combines the echoes by taking the minimum pixel value from all the echoes.
•
Screen
Emulates combining the echoes by sandwiching them optically. This is similar to Add, but it will not
overload as quickly.
•
Composite In Back
Uses the echoes’ alpha channels to composite them back to front.
•
Composite In Front
Uses the echoes’ alpha channels to composite them front to back.
Posterize Time effect
The Posterize Time effect locks a clip to a specific frame rate. Posterize Time is useful on its own as a special effect,
but it also has more subtle uses. For example, 60-field video footage can be locked to 24 fps (and then field-rendered
at 60 fields per second) to give a film-like look. This effect is sometimes called Strobe in hardware devices.