Backlighting and Light Wrap

Backlighting and Light Wrap

The conditions of a backlit scene are a classic example
where the compositor often does not go far enough to
match what actually happens in the real world.
This technique is designed for scenes that contain backlighting
conditions and a foreground that, although it
may be lit to match those conditions, lacks light wrapping
around the edges.

Set up a light wrap effect as follows:
1. Create a new composition that contains the background
and foreground layers, exactly as they are
positioned and animated in the master composition.
You can do this simply by duplicating the master comp
and renaming it something intuitive, such as Light
Wrap. If the foreground or background consists of
several layers, it will probably be simpler to precompose
them into two layers, one each for the foreground and
background.
2. Set Silhouette Alpha blending mode for the foreground
layer, punching a hole in the background.
3. Add an adjustment layer at the top, and apply Fast Blur.
4. In Fast Blur, check the Repeat Edge Pixels toggle on
and crank up the blurriness.
5. Duplicate the foreground layer, move the copy to the
top, and set its blending mode to Stencil Alpha, leaving
a halo of background color that matches the shape of
the foreground ( top). If the light source is
not directly behind the subject, you can offset this layer
to match, producing more light on the matching side.
6. Place the resulting comp in the master comp and adjust
opacity (and optionally switch the blending mode to
Add, Screen, or Lighten) until you have what you’re
after. You may need to go back to the Light Wrap comp
to further adjust the blur.

When there is no fi ll light on the foreground subject
whatsoever, most cameras are incapable of picking up as
much detail in the foreground as your eye might see. In
your reference photo, an unlit foreground subject might
appear completely silhouetted. Because the foreground
subjects are often the stars of the scene, you might have to
compensate, allowing enough light and detail in the foreground
that the viewer can see facial expressions and other
important dramatic detail.
In other words, this might be a case where your reference
confl icts with what is needed for the story. Try to strike a
balance, but remember, when the story loses, nobody wins.