Merge PR #386

crates/engine/src/camera_preview.rs

@@ -1179,15 +1179,17 @@ mod tests {
         assert!(fit_pairs(&sensor, &reference).is_none());
     }
 
-    /// X-Trans and 16-bit Bayer RAFs use the same fixed fit at thumbnail and export sizes;
-    /// a poor reference keeps the fallback. Skips cleanly without these CC0 corpus files.
+    /// X-Trans and 16-bit Bayer RAFs use the same fixed fit at thumbnail and export sizes.
+    /// The X-T20 fails the gates on all pixels (held-out RMS 0.114 against 0.10) and passes away
+    /// from edges (0.056, issue #232), so it is fitted too. Skips cleanly without these CC0
+    /// corpus files.
     #[test]
     fn corpus_raf_colour_and_white_balance() {
         let dir = std::env::var_os("LIGHTCRAFT_CORPUS")
             .map(std::path::PathBuf::from)
             .unwrap_or_else(|| std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("../../corpus"))
             .join("raw");
-        for (name, accepted) in [("raf-fuji-xt2-865.raf", true), ("raf-fuji-gfx100s-4503.raf", true), ("raf-fuji-xt20-compressed.raf", false)] {
+        for (name, accepted) in [("raf-fuji-xt2-865.raf", true), ("raf-fuji-gfx100s-4503.raf", true), ("raf-fuji-xt20-compressed.raf", true)] {
             let Ok(bytes) = std::fs::read(dir.join(name)) else { continue };
             let header = crate::files::probe_bytes(name, &bytes).unwrap();
             assert_eq!(header.as_shot_wb, Some((6500.0, 0.0)), "{name}");

docs/camera-preview-colour.md

@@ -56,7 +56,7 @@ The additional supplied folder contains 748 RAFs. Profiles were fitted separatel
 
 For validation, every fifth usable photo of each model in sorted path order was withheld. Profiles trained on the remaining 160 X-H2S and 436 X-T4 photos were tested on 41 and 109 withheld photos. Mean CIE76 ΔE against the camera JPEG was 9.86 → 1.70 with per-file fitting → 1.62 with the pooled X-H2S profile, and 13.64 → 2.43 → 2.34 for X-T4. The profiles improved 108 of 150 files; the largest regression against per-file fitting was 0.60 ΔE, with no previously accepted fit rejected. These are withheld files from the same limited scene collection, not independent coverage of all subjects or illuminants.
 
-The three original dark X-H2S wrench files have too little colour variation to learn a matrix, but now use the known profile to fit tone: ΔE 8.74 → 2.25, all accepted. The four original X-T4 files and two public X-T4 files remain accepted with the final bundled profile; they regress slightly against their own per-file fits (six-file mean 4.72 → 4.94), while remaining much closer than the neutral fallback (13.47). One public X-T20 reference still fails the gates and keeps the fallback.
+The three original dark X-H2S wrench files have too little colour variation to learn a matrix, but now use the known profile to fit tone: ΔE 8.74 → 2.25, all accepted. The four original X-T4 files and two public X-T4 files remain accepted with the final bundled profile; they regress slightly against their own per-file fits (six-file mean 4.72 → 4.94), while remaining much closer than the neutral fallback (13.47). The public X-T20 reference fails the gates on all pixels (held-out RMS 0.114) and passes on the second attempt away from edges (0.056, from 0.185 uncorrected), so it is fitted too.
 
 RAF inputs also work with `lightcraft-cli calibrate`. Tests cover real X-Trans/16-bit Bayer fits, profile use on dull scenes, per-file fitting after profile rejection, monochrome rejection, resolution independence, header/decoded relative WB, old-catalog WB transitions and invalid RAF calibration inputs. A full-size 6240×4160 X-T4 JPEG export also succeeded.