Cause: float footage (OpenEXR, float TIFF) was always sRGB-encoded on
decode, and Interpret Footage could not turn that off, so an OCIO effect
on the layer converted values that were already encoded.
Fix: After Effects' Interpret Footage ▸ Color ▸ Preserve RGB
(Footage::preserve_rgb; file.interpretFootage {"preserveRgb": true}; a
checkbox in the Interpret Footage form; Remember / Apply Interpretation
carry it). The decoder keeps float values linear, and the working-space
conversion from the colour profile and Interpret As Linear Light don't
apply, so the file's values enter the composition unconverted. The media
cache key includes the flag, so both interpretations decode separately.
Tests: pool::preserve_rgb_reads_float_exr_values_unconverted,
tests_color::preserve_rgb_footage_is_not_converted (managed, linearized
and not), tests_proxy::guess_alpha_invert_and_linear_light (command,
render, Apply Interpretation).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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