Place
the shot you wish the enhance on the first video layer on
the timeline (V1). In this example I am using the ChurchSkyline.tga
Next add
the Gradient Designer effect on the timeline below the skyline
(on V2).
Setup
a gradient in the effect, simulating a gradient akin to a
camera filter you may use during acquisition (eg: Cokin filters).
The Gradient effect should come preset to a linear gradient
from lower left red to upper right green, close to the desired
result. First align the two control points (labeled 0 &
1 in the Item Info window).

To align the control points, select the Video tab of the Item
Info window. Next, highlight the Gradient effect on the timeline.
Click above the effect the render a single frame preview of
the effect - a red to green gradient appears. You will also
see the gradient and two control nodes in both the playback
window and the result window. Grab each node, one at a time,
and center it horizontally. As mentioned before, Speed Razor
allows several different ways of accomplishing the same task.
The quick, easy, and most precise way is to go to the Item
Info window and adjust the numeric values for the control
nodes. First double click on the numeric value for "Point
0 x," press 0 on your keyboard and viola, the point is
now centered on the X-axis. Repeat this for "Point 1
x" and your gradient orientation is all set.
Next lets
choose the color to add to the sky. Based on the same starting
point as the effect preset, RGB 1 will be the uppermost color
in our gradient - applied to the sky - and RGB 0 will be the
color applied to the skyline. First select any of the first
three color picker buttons (to the right of Red 0, Green 0,
or Blue 0). This will bring up the picker dialog box. Since
this is the skyline color, and we do not want to alter that,
we'll choose a neutral shade of gray. For RGB 1 we'll choose
a nice blue to give the sky a little color (also, <....pst
LINK:here> is a preset that includes a few color sky gradients
to start you off).