LR-EDIT-CALIB: Calibration — shadows tint and R/G/B primary hue/saturation

White-preserving primaries matrix (OkLCh hue rotation / chroma scale of each Rec.2020
primary) plus a luminance-preserving green/magenta shadows tint, applied in scene-linear
light before the tone map. CPU (colorops::calibrate) and GPU (finish.wgsl) with an
equivalence case; seven control specs (calibration.*), a settings group, crs: import
(ShadowTint, Red/Green/BlueHue/Saturation) and a Calibration section at the bottom of the
Edit panel.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/develop/src/controls.rs

@@ -22,6 +22,7 @@ pub enum Section {
     Optics,
     Geometry,
     Profile,
+    Calibration,
 }
 
 impl Section {
@@ -40,6 +41,7 @@ impl Section {
             Section::Optics => "Optics",
             Section::Geometry => "Geometry",
             Section::Profile => "Profile",
+            Section::Calibration => "Calibration",
         }
     }
 }
@@ -227,6 +229,13 @@ controls! {
     "geometry.scale" => geometry.scale, "Scale", Geometry, 50, 150, 100, 1, 0, Plain;
     "geometry.offsetX" => geometry.offset_x, "Offset X", Geometry, -100, 100, 0, 0.1, 1, Centered;
     "geometry.offsetY" => geometry.offset_y, "Offset Y", Geometry, -100, 100, 0, 0.1, 1, Centered;
+    "calibration.shadowsTint" => calibration.shadows_tint, "Shadows Tint", Calibration, -100, 100, 0, 1, 0, Tint;
+    "calibration.redHue" => calibration.red_hue, "Red Hue", Calibration, -100, 100, 0, 1, 0, Gradient { from: "#e0306a", to: "#e08a30" };
+    "calibration.redSat" => calibration.red_sat, "Red Saturation", Calibration, -100, 100, 0, 1, 0, Gradient { from: "#7a7a7a", to: "#e03a3a" };
+    "calibration.greenHue" => calibration.green_hue, "Green Hue", Calibration, -100, 100, 0, 1, 0, Gradient { from: "#b0c030", to: "#30c08a" };
+    "calibration.greenSat" => calibration.green_sat, "Green Saturation", Calibration, -100, 100, 0, 1, 0, Gradient { from: "#7a7a7a", to: "#40b050" };
+    "calibration.blueHue" => calibration.blue_hue, "Blue Hue", Calibration, -100, 100, 0, 1, 0, Gradient { from: "#30a0d0", to: "#8040d0" };
+    "calibration.blueSat" => calibration.blue_sat, "Blue Saturation", Calibration, -100, 100, 0, 1, 0, Gradient { from: "#7a7a7a", to: "#3a60e0" };
     "crop.angle" => crop.geometry.angle, "Straighten", Geometry, -45, 45, 0, 0.01, 2, Centered;
 }
 

crates/develop/src/presets.rs

@@ -32,10 +32,11 @@ pub enum SettingsGroup {
     Spots,
     RedEye,
     LensBlur,
+    Calibration,
 }
 
 impl SettingsGroup {
-    pub const ALL: [SettingsGroup; 19] = [
+    pub const ALL: [SettingsGroup; 20] = [
         SettingsGroup::Profile,
         SettingsGroup::Treatment,
         SettingsGroup::WhiteBalance,
@@ -55,6 +56,7 @@ impl SettingsGroup {
         SettingsGroup::Spots,
         SettingsGroup::RedEye,
         SettingsGroup::LensBlur,
+        SettingsGroup::Calibration,
     ];
 
     /// Groups included by default when copying (Lightroom excludes crop, masks and spots by default).
@@ -86,6 +88,7 @@ impl SettingsGroup {
             SettingsGroup::Spots => "Remove",
             SettingsGroup::RedEye => "Red Eye",
             SettingsGroup::LensBlur => "Lens Blur",
+            SettingsGroup::Calibration => "Calibration",
         }
     }
 
@@ -111,6 +114,7 @@ impl SettingsGroup {
             SettingsGroup::Spots => &["spots"],
             SettingsGroup::RedEye => &["red_eye"],
             SettingsGroup::LensBlur => &["lens_blur"],
+            SettingsGroup::Calibration => &["calibration"],
         }
     }
 }

crates/develop/src/settings.rs

@@ -32,6 +32,8 @@ pub struct DevelopSettings {
     pub red_eye: Vec<RedEye>,
     pub lens_blur: LensBlur,
     pub enhance: Enhance,
+    /// Camera calibration: shadows tint and primary hue/saturation (applied before tone mapping).
+    pub calibration: Calibration,
     /// Section on/off toggles (the "eye" buttons on panel headers): section id → enabled.
     pub disabled_sections: Vec<String>,
 }
@@ -62,6 +64,7 @@ impl Default for DevelopSettings {
             red_eye: Vec::new(),
             lens_blur: LensBlur::default(),
             enhance: Enhance::default(),
+            calibration: Calibration::default(),
             disabled_sections: Vec::new(),
         }
     }
@@ -319,6 +322,31 @@ impl ColorGrading {
     }
 }
 
+/// Camera calibration (Lightroom Classic's Calibration panel): a green/magenta tint of the shadows,
+/// and a hue rotation / saturation scale of each working-space primary (−100..100), i.e. a
+/// white-preserving 3×3 matrix applied in scene-linear light before tone mapping.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Serialize, Deserialize)]
+#[serde(default)]
+pub struct Calibration {
+    pub shadows_tint: f64,
+    pub red_hue: f64,
+    pub red_sat: f64,
+    pub green_hue: f64,
+    pub green_sat: f64,
+    pub blue_hue: f64,
+    pub blue_sat: f64,
+}
+
+impl Calibration {
+    /// (hue, saturation) of the red, green and blue primaries.
+    pub fn primaries(&self) -> [(f64, f64); 3] {
+        [(self.red_hue, self.red_sat), (self.green_hue, self.green_sat), (self.blue_hue, self.blue_sat)]
+    }
+    pub fn is_neutral(&self) -> bool {
+        *self == Calibration::default()
+    }
+}
+
 #[derive(Clone, Copy, Debug, Default, PartialEq, Serialize, Deserialize)]
 #[serde(default)]
 pub struct Effects {