32-Bit HDR Compositing and Color Management

32-Bit HDR Compositing
and Color Management


Whether you are directly aware of limitations or not,
you no doubt realize that there are limits to the ways
images are processed and displayed on a computer. Your
monitor likely only displays 8 bits of color per channel, and
while its size (in pixel dimensions) has steadily increased
over the last few years, this color depth limitation has
hardly budged.
You may also be aware that although an After Effects project,
by default, operates in the same limited 8-bit-per-channel
mode as your monitor, this is hardly the optimal way
to create an image. Other modes, models, and methods
for color are available, including high-bit depths, alternate
color spaces, and color management, and few topics in
After Effects generate as much curiosity or confusion as
these. Each of the features detailed here improves upon
the standard digital color model you know best, but at the
cost of requiring better understanding on your part.
In After Effects CS4 the process centers around Color Management,
whose name would seem to imply that it is an
automated process to manage colors for you, when in fact
it is a complex set of tools allowing (even requiring) you to
effectively manage color.
On the other hand, 32-bit High Dynamic Range (HDR)
compositing is routinely ignored by artists who could

benefi t from it, despite that it remains uncommon for
source fi les to contain over-range color data, which are
pixel values too bright for your monitor to display.
Film can and typically does contain these over-range color
values. These are most often brought into After Effects as
10-bit log Cineon or DPX fi les, and importing, converting,
and writing this format requires a bit of special knowledge.
It’s an elegant and highly standardized system that has relevance
even when you’re working with the most up-to-date,
high-end digital cameras.