Floating Point Files

Floating Point Files

As you’ve already seen, there is one class of files
that does not need to be converted to linear space:
floating point files. These files are already storing
scene-referred values, complete with overbright
information. Common formats supported by After
Effects are Radiance (.hdr) and floating point .tiff,
not to mention .psd, but the most universal and
versatile is Industrial Light + Magic’s OpenEXR
format. OpenEXR uses efficient 16-bit floating
point pixels, can store any number of image channels,
supports lossless compression, and is already
supported by most 3D programs thanks to being an
open source format.
After Effects CS4 offers expanded support of the
OpenEXR format by bundling plug-ins from fnord
software, which provide access to multiple layers
and channels within these files. EXtractoR can
open any floating point image channel in an EXR
file, and Identifier can open the other, non-image
channels such as Object and Material ID.