Conflicts with issue #150 (NEF colour from the camera JPEG): the per-file
look, its hue/saturation/value table and chroma curve, and camera
profiles now apply to every `file_local_look` format (ARW, NEF, NRW);
`calibrate` also collects NEF/NRW. Render cache version 11 (main 9,
branch 10).
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
One photo can show too little of a colour for its own fit: a lime shirt
covering a few dozen proxy pixels next to foliage at the same hue stayed
yellow (hue 68 deg vs the JPEG's 82 deg).
- `lightcraft-cli calibrate [--max N] [--out DIR] FOLDERS...` pools the
colour pairs of many ARWs per model (each against its embedded JPEG,
192 px proxies, <= 4000 pairs per photo) and fits one matrix from
white-balanced camera RGB plus a hue/saturation/value table.
- Profiles live in $LIGHTCRAFT_CAMERA_PROFILES or
<config>/camera-profiles/<model>.json; validated on load, damaged files
ignored with a warning, part of the render cache keys.
- Photos of a profiled model take its colour and fit only their own tone
and chroma curves; the acceptance gates still apply.
- The table fit buckets samples by hue and runs nodes in parallel; the
app's config_dir moves to the engine.
Profile from 300 Feb-Aug ILCE-7M4 photos (2 min); 29 held-out September
photos: mean dE vs camera JPEG 3.54 -> 3.10, saturated 6.41 -> 5.20;
the shirt's hue 68 -> 82 deg (JPEG 81.5).
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
A sunny ILCE-7M4 waterfall shot rendered yellow: sunlit rock came out
cream, +4 b* in the brightest fifth of the picture. Camera JPEGs make
shadows up to 1.4x more colourful and bleach highlights to 0.1-0.3x
(a per-channel tone curve), which a luminance-only curve can't do.
- CameraTone gains an 8-node chroma-by-display-luminance curve, fitted
per file (bright pixels included) and kept only when it lowers the
held-out error; applied after the tone map on CPU and GPU, keeping
luminance. Old smart-preview headers load with an identity curve.
- The hue/saturation table gets an sRGB-encoded value axis: dark yellows
had to turn toward orange while bright yellow-greens turned toward
green. It is applied after the baseline exposure, as it is fitted.
- Matrix-only and matrix+table looks are completed (tone, chroma) and
compared in gamma-encoded values; acceptance gates stay linear.
29 local ARWs vs their camera JPEGs: mean dE 4.23 -> 3.54, every file
closer, saturated areas 7.65 -> 6.41. Render cache v10.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
A global 3x3 matrix can't follow the camera's hue-dependent rendering:
on an ILCE-7M4 photo of a lime shirt among grey rocks the best matrix
rendered the shirt olive (16 deg hue error), since the few saturated
pixels carry little weight and a matrix fitted to them breaks the rest.
After the matrix, fit a 72x5 hue/saturation table (DNG ProfileHueSatMap
layout, linear ProPhoto) to the residual hue shifts and saturation
ratios: kernel-weighted per node, shrunk to identity where samples are
sparse, identity at saturation 0. It preserves luminance (the tone curve
owns it) and is kept only when it lowers the held-out error.
28 local ILCE-7M4 ARWs: mean dE vs camera JPEG 4.74 -> 4.27, none worse
overall; the shirt's hue error drops to 6-8 deg. Render cache v9.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
LightCraft has no colour matrix for Nikon cameras. Because of this, NEF
files showed colours that were too gray and too green.
- Colour: LightCraft now calculates a colour matrix and a tone curve from
the JPEG preview in each NEF file. Sony ARW files use the same
procedure and the same quality checks. White balance is relative to
the as-shot look, as for ARW files.
- One function, camera_preview::file_local_look, selects the formats for
the fit and for the relative white balance. Photo::relative_wb in the
catalog uses the same formats.
- Black level: Nikon stores the black level (maker note 0x003d) in
14-bit units, also in 12-bit files. The decoder read it as a 12-bit
value. Because of this, 12-bit files from the D750, D780, D850, D7500
and Z 50 were too dark. Now the decoder divides the value by 4 for
12-bit files.
- The corpus gets the D7500 12-bit and 14-bit lossless samples. A test
compares their levels. The render cache version increases to 9.
Results on 13 NEF files that LightCraft can decode: LightCraft accepted
the fit for all 13 files. The mean colour difference from the camera
JPEG (CIE76 dE) decreased from 13-46 to 2.9-7.8. One file with mixed
light improved by a small quantity only (12.7 to 12.0).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The 0.055 cap rejected half of the public Sony samples tried (ILCE-6400,
ILCE-6700, ILCE-7M4) although their fits were 1.5-3x closer to the
camera JPEG than the fallback and visibly better (mean dE vs the embedded
preview 19-26 -> 5-10). Unrelated previews stay rejected (synthetic test
lands at 0.115).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
