Collage (The Digital Advantage) - Frame-by-Frame Stop Motion: The Guide to Non-Traditional Animation Techniques - page 135

can import Quicktimes and image sequences. A timeline in this Photoshop
allows you to work on individual frames in a sequence. Ultimately, this is a slow,
meticulous process and requires careful scrutiny on a frame-by-frame basis. No
matter what approach you take, the goal is to place the clean plate on every
animation frame that has a rig or cleanup issue as a background layer. It can be
helpful to use a rig support that has a different color than your model so the
delineation of the two elements is easier to distinguish. Carefully erase the rig
and rig shadows of the animation frame on the top layer, revealing the clean
plate behind it. These should match in placement, color, and light. I often use
a small, slightly feathered eraser at the interface point of the rig and animated
object being supported. It is possible to use a larger feathered eraser for the
rest of the rig, because the rest of the rig is less critical in its placement.
Fig 10.10 the eraser tool wiping
out a rig.
Once all your frames have been cleaned, which should include any camera dirt
or burned out pixels from the image sensor, you want to re-export those new
frames to a Quicktime movie. Often you do not see some of the more subtle
imperfections in a shot until you see it in “running time.” You may have to go back
and address those problems for the particular frames that need additional work.
The Chroma Key
Chroma keying is becoming more prevalent in stop motion, because it allows
an animator to work with individual components or objects separately in any
shot. This often saves space and massive set building. There are many uses for
chroma keying, so I asked Jeff Sias, who, along with his partner Bryan Papciak,
run a small studio in Boston called Handcranked Productions, to create a
chroma key exercise that explains the process.
Chroma keying is a compositing term, meaning that anything of a
particular color in frame will be eliminated through the process of “keying
out” that color. If shooting with a green screen, then anything green
in frame will be removed and become transparent. This allows you to
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