LibRaw is deliberately kept out of white balance and tone here, so a RAW opened
in the studio lands on the neutral demosaic — while the JPEG on the back of the
camera carried the body's own rendering. cameraMatch.ts holds that difference as
one 3x3 per body, fitted offline against the camera's own preview of the same
frame and applied in the develop shader right after the sRGB encode.
Measured on held-out blocks, mean CIEDE2000 against the camera preview:
GR III 5.99 -> 4.28 X100V 8.19 -> 4.22
GR II 11.68 -> 9.73 X100S 7.41 -> 7.27
X-T3 9.03 -> 6.12
The matrix is fitted luma-preserving and the shader holds that exactly, so the
profile moves colour and never exposure: a preview that came out dark stays
dark, by design. What is left over is largely high-frequency (sharpening, noise
reduction, demosaic) — the error keeps falling as the blocks grow.
The fits are weak evidence on their own. Validation on colour charts came out
poor: the daylight chart is an Adobe DNG Converter export that aligns to the
body's own develop at only 0.785 correlation and gets worse with the profile
applied, and the tungsten chart is a different illuminant entirely. The honest
claims are the self-fit numbers above and that the X100S — whose cast was small
to begin with — barely moves.
Verified end to end through the real develop: an unfitted body (Sony ILME-FX30)
develops byte-for-byte identically to before, and reading the matrix back out of
each profiled develop recovers the fitted one.
ponytail: one matrix per body, no tone curve and no 3D LUT (a curve on top
measured 2% better and needs a spline plus array uniforms). The match is applied
to the 8-bit band the develop already produces — give develop 16-bit output if a
profile ever has to grade rather than match.
3dtours
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