Every point operation ran in camera RGB and the camera matrix came after
them all, against the order ARCH §5.2 draws. So `luminance()` applied
Rec.709 weights to a body's own primaries, a band in the colour mixer
was a different hue on every make of sensor, and the vibrance skin guard
tested channel order in a space where skin does not have one.
Operations now declare a `Stage`. White balance is the only camera-stage
node — its multipliers scale the sensor's channels, and after a matrix
that mixes them the same numbers are a different correction — and says
so with `stage: camera` in its YAML, a key both the build-time generator
and the load-time declared op read. The composer emits the camera nodes,
then the matrix, then the rest, each group in graph order; an empty
chain still gets the matrix.
Film simulation stops converting out of camera space itself, since it is
now handed working-space colour like every other scene node. The base
curve stays where it was, after the operations, and so now acts on
working-space colour; the next commit replaces it (D19).
dtourolle
db7b84795c