diff --git a/LICENSE-delaunator b/LICENSE-delaunator
new file mode 100644
index 0000000..d552272
--- /dev/null
+++ b/LICENSE-delaunator
@@ -0,0 +1,15 @@
+ISC License
+
+Copyright (c) 2017, Mapbox
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/src-tauri/Cargo.lock b/src-tauri/Cargo.lock
index 61cd4d4..0ab1ad3 100644
--- a/src-tauri/Cargo.lock
+++ b/src-tauri/Cargo.lock
@@ -1579,6 +1579,7 @@ dependencies = [
 name = "iccery"
 version = "0.1.0"
 dependencies = [
+ "base64 0.22.1",
  "serde",
  "serde_json",
  "tauri",
diff --git a/src-tauri/Cargo.toml b/src-tauri/Cargo.toml
index 0ba1c25..060753c 100644
--- a/src-tauri/Cargo.toml
+++ b/src-tauri/Cargo.toml
@@ -24,4 +24,5 @@ serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 tokio = { version = "1", features = ["full"] }
 tauri-plugin-dialog = "2.7.2"
+base64 = "0.22"
 
diff --git a/src-tauri/argyll/linux-x86_64/chartread.mock b/src-tauri/argyll/linux-x86_64/chartread.mock
new file mode 100755
index 0000000..b05aada
--- /dev/null
+++ b/src-tauri/argyll/linux-x86_64/chartread.mock
@@ -0,0 +1,30 @@
+#!/bin/bash
+# Mock script for chartread -u
+# This script simulates the behaviour of chartread for testing purposes.
+
+echo "Place instrument on calibration tile and hit [Space] to calibrate."
+
+# We don't really wait for input, just wait 1 second
+sleep 1
+echo "Calibration successful."
+echo "Hit [Space] to read strip A (or 's' to skip)."
+
+sleep 1
+echo "Reading strip A..."
+
+# Emit mock JSON for strip A
+cat << 'EOF'
+ROW_COLORS_JSON: {"event": "row_complete", "row_id": "A", "row_index": 0, "total_rows": 2, "patch_count": 3, "patches": [{"id": "1", "loc": "A1", "is_pad": false, "device": [0.0, 50.0, 100.0], "expected": {"XYZ": [18.4210, 20.1234, 15.6789], "Lab": [51.98, -8.45, 12.32]}, "measured": {"XYZ": [18.5120, 20.0451, 15.7100], "Lab": [51.89, -8.31, 12.15]}}, {"id": "2", "loc": "A2", "is_pad": false, "device": [10.0, 60.0, 90.0], "expected": {"Lab": [60.0, 10.0, -20.0]}, "measured": {"Lab": [60.1, 10.5, -19.5]}}, {"id": "3", "loc": "A3", "is_pad": true, "device": [100.0, 100.0, 100.0]}]}
+EOF
+
+echo "Hit [Space] to read strip B (or 's' to skip)."
+sleep 1
+echo "Reading strip B..."
+
+# Emit mock JSON for strip B
+cat << 'EOF'
+ROW_COLORS_JSON: {"event": "row_complete", "row_id": "B", "row_index": 1, "total_rows": 2, "patch_count": 2, "patches": [{"id": "4", "loc": "B1", "is_pad": false, "device": [100.0, 0.0, 0.0], "expected": {"Lab": [40.0, 40.0, 40.0]}, "measured": {"Lab": [38.0, 41.0, 39.0]}}, {"id": "5", "loc": "B2", "is_pad": false, "device": [0.0, 100.0, 0.0], "expected": {"Lab": [80.0, -50.0, 50.0]}, "measured": {"Lab": [79.0, -49.0, 51.0]}}]}
+EOF
+
+echo "Ready to read... done."
+exit 0
diff --git a/src-tauri/argyll/linux-x86_64/colprof.mock b/src-tauri/argyll/linux-x86_64/colprof.mock
new file mode 100755
index 0000000..8bbd22c
--- /dev/null
+++ b/src-tauri/argyll/linux-x86_64/colprof.mock
@@ -0,0 +1,20 @@
+#!/bin/bash
+# Mock script for colprof
+# Simulates colprof execution and outputs progress log
+
+basename="$1"
+# Find last argument if -D or other flags are used
+for arg in "$@"; do
+    basename="$arg"
+done
+
+echo "colprof: Starting profile calculation for $basename"
+sleep 1
+echo "Gamut mapping calculation..."
+sleep 1
+echo "Fitting cLUT grid points..."
+sleep 1
+echo "Writing ICC profile $basename.icc..."
+touch "$basename.icc"
+echo "Done."
+exit 0
diff --git a/src-tauri/argyll/linux-x86_64/profcheck.mock b/src-tauri/argyll/linux-x86_64/profcheck.mock
new file mode 100755
index 0000000..78da1f3
--- /dev/null
+++ b/src-tauri/argyll/linux-x86_64/profcheck.mock
@@ -0,0 +1,14 @@
+#!/bin/bash
+# Mock script for profcheck
+# Simulates profcheck verification output
+
+echo "profcheck: Checking profile accuracy..."
+sleep 1
+cat << 'EOF'
+{"event": "profcheck_complete", "avg_de": 0.85, "max_de": 2.41, "rms_de": 1.02}
+EOF
+echo "Summary:"
+echo "  avg. dE = 0.85"
+echo "  max. dE = 2.41"
+echo "  rms. dE = 1.02"
+exit 0
diff --git a/src-tauri/argyll/reference_gamuts/sRGB.gam b/src-tauri/argyll/reference_gamuts/sRGB.gam
new file mode 100644
index 0000000..9826a02
--- /dev/null
+++ b/src-tauri/argyll/reference_gamuts/sRGB.gam
@@ -0,0 +1,16 @@
+CGATS.17
+NUMBER_OF_FIELDS 4
+BEGIN_DATA_FORMAT
+INDEX LAB_L LAB_A LAB_B
+END_DATA_FORMAT
+NUMBER_OF_SETS 8
+BEGIN_DATA
+0 0.0 0.0 0.0
+1 100.0 0.0 0.0
+2 53.2 80.1 67.2
+3 87.7 -86.2 83.2
+4 97.1 -21.6 94.5
+5 32.3 79.2 -107.9
+6 60.3 98.2 -60.8
+7 91.1 -48.1 -14.1
+END_DATA
diff --git a/src-tauri/src/commands.rs b/src-tauri/src/commands.rs
index 314cdc1..1cd540d 100644
--- a/src-tauri/src/commands.rs
+++ b/src-tauri/src/commands.rs
@@ -32,27 +32,62 @@ pub async fn kill_process(
 
 #[tauri::command]
 pub async fn resolve_binary(app: AppHandle, binary_name: String) -> Result<String, String> {
-    // Resolve sidecar resource path
+    let settings = crate::settings::load_settings(app.clone()).unwrap_or_default();
+    if let Some(dir) = settings.argyll_binary_dir {
+        if !dir.trim().is_empty() {
+            let custom_path = std::path::Path::new(&dir).join(&binary_name);
+            if custom_path.exists() {
+                return Ok(custom_path.to_string_lossy().to_string());
+            }
+        }
+    }
+
+    let platform = match (std::env::consts::OS, std::env::consts::ARCH) {
+        ("linux", "x86_64") => "linux-x86_64",
+        ("windows", "x86_64") => "windows-x86_64",
+        ("macos", "aarch64") => "macos-aarch64",
+        _ => "linux-x86_64",
+    };
+
     let resource_path = app
         .path()
         .resolve(
-            format!("argyll/linux-x86_64/{}", binary_name),
+            format!("argyll/{}/{}", platform, binary_name),
             tauri::path::BaseDirectory::Resource,
         )
         .map_err(|e| e.to_string())?;
 
-    // In a real app we'd switch based on target_os, but for Milestone 1 scaffolding we'll mock the linux path.
     Ok(resource_path.to_string_lossy().to_string())
 }
 
 #[tauri::command]
-pub async fn list_instruments(app: AppHandle, state: State<'_, ProcessManager>) -> Result<(), String> {
-    // We would use spawn_process directly with instlist binary and parse JSON output.
-    // For scaffolding, this is a placeholder.
+pub async fn detect_instruments(app: AppHandle, state: State<'_, ProcessManager>) -> Result<(), String> {
     let binary = resolve_binary(app.clone(), "instlist".to_string()).await?;
     state.spawn(app, "instlist".to_string(), binary, vec![], None).await
 }
 
+#[tauri::command]
+pub async fn extract_gamut(
+    app: AppHandle,
+    state: State<'_, ProcessManager>,
+    icc_path: String,
+) -> Result<(), String> {
+    let binary = resolve_binary(app.clone(), "iccgamut".to_string()).await?;
+    let path = std::path::Path::new(&icc_path);
+    let basename = path.file_stem().unwrap().to_str().unwrap();
+    let parent_dir = path.parent().map(|p| p.to_str().unwrap()).unwrap_or("");
+    
+    let mut args = vec!["-w".to_string()];
+    if !parent_dir.is_empty() {
+        args.push("-d".to_string());
+        args.push(parent_dir.to_string());
+    }
+    args.push(icc_path.clone());
+    
+    let id = format!("iccgamut_{}", basename);
+    state.spawn(app, id, binary, args, None).await
+}
+
 #[derive(Debug, Deserialize, Serialize)]
 pub struct TargenConfig {
     pub colour_space: String,
@@ -63,6 +98,16 @@ pub struct TargenConfig {
     pub cwd: String,
 }
 
+#[derive(Debug, Deserialize, Serialize)]
+pub struct PrinttargConfig {
+    pub instrument: String,   // One of: "i1", "p3", "CM", "SS", "20", "22", "41", "51"
+    pub page_size: String,    // One of: "A4", "A4R", "A3", "A2", "Letter", "LetterR", "Legal", "4x6", "11x17", or "WWWxHHH"
+    pub bit_depth: u8,        // 8 or 16
+    pub dpi: u32,             // TIFF resolution, e.g. 100, 200, 300
+    pub basename: String,     // Must match the .ti1 basename from Stage 1
+    pub cwd: String,          // Working directory where the .ti1 file resides
+}
+
 pub fn build_targen_args(config: &TargenConfig) -> Vec<String> {
     let mut args = vec![
         "-v".to_string(),
@@ -92,6 +137,27 @@ pub fn build_targen_args(config: &TargenConfig) -> Vec<String> {
     args
 }
 
+pub fn build_printtarg_args(config: &PrinttargConfig) -> Vec<String> {
+    let mut args = vec![
+        "-v".to_string(),
+        "-u".to_string(),
+        "-i".to_string(),
+        config.instrument.clone(),
+        "-p".to_string(),
+        config.page_size.clone(),
+    ];
+
+    if config.bit_depth == 16 {
+        args.push("-T".to_string());
+    } else {
+        args.push("-t".to_string());
+    }
+    args.push(config.dpi.to_string());
+
+    args.push(config.basename.clone());
+    args
+}
+
 #[tauri::command]
 pub async fn run_targen(
     app: AppHandle,
@@ -113,6 +179,154 @@ pub async fn run_targen(
     state.spawn(app, id, binary, args, cwd).await
 }
 
+#[tauri::command]
+pub async fn run_printtarg(
+    app: AppHandle,
+    state: State<'_, ProcessManager>,
+    config: PrinttargConfig,
+) -> Result<(), String> {
+    let binary = resolve_binary(app.clone(), "printtarg".to_string()).await?;
+    let args = build_printtarg_args(&config);
+    let id = format!("printtarg_{}", config.basename);
+
+    let cwd = if config.cwd.trim().is_empty() {
+        None
+    } else {
+        Some(config.cwd.clone())
+    };
+
+    state.spawn(app, id, binary, args, cwd).await
+}
+
+#[tauri::command]
+pub async fn read_file_base64(path: String) -> Result<String, String> {
+    use std::fs;
+    let bytes = fs::read(&path).map_err(|e| format!("Failed to read {}: {}", path, e))?;
+    use base64::Engine;
+    Ok(base64::engine::general_purpose::STANDARD.encode(&bytes))
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct ChartreadConfig {
+    pub basename: String,
+    pub cwd: String,
+}
+
+pub fn build_chartread_args(config: &ChartreadConfig) -> Vec<String> {
+    vec![
+        "-v".to_string(),
+        "-u".to_string(),
+        config.basename.clone(),
+    ]
+}
+
+#[tauri::command]
+pub async fn run_chartread(
+    app: AppHandle,
+    state: State<'_, ProcessManager>,
+    config: ChartreadConfig,
+) -> Result<(), String> {
+    let binary = resolve_binary(app.clone(), "chartread".to_string()).await?;
+    let args = build_chartread_args(&config);
+    let id = format!("chartread_{}", config.basename);
+
+    let cwd = if config.cwd.trim().is_empty() {
+        None
+    } else {
+        Some(config.cwd.clone())
+    };
+
+    state.spawn(app, id, binary, args, cwd).await
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct ColprofConfig {
+    pub quality: String,
+    pub algorithm: String,
+    pub description: String,
+    pub copyright: Option<String>,
+    pub basename: String,
+    pub cwd: String,
+}
+
+pub fn build_colprof_args(config: &ColprofConfig) -> Vec<String> {
+    let mut args = vec![
+        "-v".to_string(),
+        "-u".to_string(),
+        "-q".to_string(),
+        config.quality.clone(),
+        "-a".to_string(),
+        config.algorithm.clone(),
+        "-D".to_string(),
+        config.description.clone(),
+    ];
+
+    if let Some(copyright) = &config.copyright {
+        if !copyright.trim().is_empty() {
+            args.push("-C".to_string());
+            args.push(copyright.clone());
+        }
+    }
+
+    args.push(config.basename.clone());
+    args
+}
+
+#[tauri::command]
+pub async fn run_colprof(
+    app: AppHandle,
+    state: State<'_, ProcessManager>,
+    config: ColprofConfig,
+) -> Result<(), String> {
+    let binary = resolve_binary(app.clone(), "colprof".to_string()).await?;
+    let args = build_colprof_args(&config);
+    let id = format!("colprof_{}", config.basename);
+
+    let cwd = if config.cwd.trim().is_empty() {
+        None
+    } else {
+        Some(config.cwd.clone())
+    };
+
+    state.spawn(app, id, binary, args, cwd).await
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct ProfcheckConfig {
+    pub ti3_path: String,
+    pub icc_path: String,
+    pub cwd: String,
+}
+
+pub fn build_profcheck_args(config: &ProfcheckConfig) -> Vec<String> {
+    vec![
+        "-v".to_string(),
+        "-k".to_string(),
+        "-u".to_string(),
+        config.ti3_path.clone(),
+        config.icc_path.clone(),
+    ]
+}
+
+#[tauri::command]
+pub async fn run_profcheck(
+    app: AppHandle,
+    state: State<'_, ProcessManager>,
+    config: ProfcheckConfig,
+) -> Result<(), String> {
+    let binary = resolve_binary(app.clone(), "profcheck".to_string()).await?;
+    let args = build_profcheck_args(&config);
+    let id = format!("profcheck_{}", config.ti3_path);
+
+    let cwd = if config.cwd.trim().is_empty() {
+        None
+    } else {
+        Some(config.cwd.clone())
+    };
+
+    state.spawn(app, id, binary, args, cwd).await
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -144,4 +358,84 @@ mod tests {
         let args = build_targen_args(&config);
         assert_eq!(args, vec!["-v", "-d", "4", "-f", "1500", "-B", "8", "cmyk_profile"]);
     }
+
+    #[test]
+    fn test_build_printtarg_args_i1_a4_8bit() {
+        let config = PrinttargConfig {
+            instrument: "i1".to_string(),
+            page_size: "A4".to_string(),
+            bit_depth: 8,
+            dpi: 100,
+            basename: "my_profile".to_string(),
+            cwd: "/tmp".to_string(),
+        };
+        let args = build_printtarg_args(&config);
+        assert_eq!(args, vec!["-v", "-u", "-i", "i1", "-p", "A4", "-t", "100", "my_profile"]);
+    }
+
+    #[test]
+    fn test_build_printtarg_args_cm_letter_16bit() {
+        let config = PrinttargConfig {
+            instrument: "CM".to_string(),
+            page_size: "Letter".to_string(),
+            bit_depth: 16,
+            dpi: 300,
+            basename: "cmyk_profile".to_string(),
+            cwd: "/home/user".to_string(),
+        };
+        let args = build_printtarg_args(&config);
+        assert_eq!(args, vec!["-v", "-u", "-i", "CM", "-p", "Letter", "-T", "300", "cmyk_profile"]);
+    }
+
+    #[test]
+    fn test_build_printtarg_args_custom_page_size() {
+        let config = PrinttargConfig {
+            instrument: "SS".to_string(),
+            page_size: "200x400".to_string(),
+            bit_depth: 8,
+            dpi: 150,
+            basename: "custom_target".to_string(),
+            cwd: "/tmp".to_string(),
+        };
+        let args = build_printtarg_args(&config);
+        assert_eq!(args, vec!["-v", "-u", "-i", "SS", "-p", "200x400", "-t", "150", "custom_target"]);
+    }
+
+    #[test]
+    fn test_build_chartread_args() {
+        let config = ChartreadConfig {
+            basename: "my_profile".to_string(),
+            cwd: "/home/user".to_string(),
+        };
+        let args = build_chartread_args(&config);
+        assert_eq!(args, vec!["-v", "-u", "my_profile"]);
+    }
+
+    #[test]
+    fn test_build_colprof_args() {
+        let config = ColprofConfig {
+            quality: "h".to_string(),
+            algorithm: "l".to_string(),
+            description: "My Profile".to_string(),
+            copyright: Some("2026 ACME".to_string()),
+            basename: "my_profile".to_string(),
+            cwd: "/home/user".to_string(),
+        };
+        let args = build_colprof_args(&config);
+        assert_eq!(
+            args,
+            vec!["-v", "-u", "-q", "h", "-a", "l", "-D", "My Profile", "-C", "2026 ACME", "my_profile"]
+        );
+    }
+
+    #[test]
+    fn test_build_profcheck_args() {
+        let config = ProfcheckConfig {
+            ti3_path: "my_profile.ti3".to_string(),
+            icc_path: "my_profile.icc".to_string(),
+            cwd: "/home/user".to_string(),
+        };
+        let args = build_profcheck_args(&config);
+        assert_eq!(args, vec!["-v", "-k", "-u", "my_profile.ti3", "my_profile.icc"]);
+    }
 }
diff --git a/src-tauri/src/events.rs b/src-tauri/src/events.rs
index cd1292f..9e665b7 100644
--- a/src-tauri/src/events.rs
+++ b/src-tauri/src/events.rs
@@ -45,3 +45,16 @@ pub fn emit_error(app: &AppHandle, id: &str, error: String) {
         error: Some(error),
     });
 }
+
+#[derive(Clone, Serialize)]
+pub struct JsonRowPayload {
+    pub id: String,
+    pub json: String,
+}
+
+pub fn emit_json_row(app: &AppHandle, id: &str, json: String) {
+    let _ = app.emit("process:json_row", JsonRowPayload {
+        id: id.to_string(),
+        json,
+    });
+}
diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index 9d1f622..15b596c 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -1,6 +1,7 @@
 mod commands;
 mod events;
 mod process_manager;
+mod settings;
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
@@ -13,8 +14,16 @@ pub fn run() {
             commands::send_stdin,
             commands::kill_process,
             commands::resolve_binary,
-            commands::list_instruments,
+            commands::detect_instruments,
+            commands::extract_gamut,
             commands::run_targen,
+            commands::run_printtarg,
+            commands::read_file_base64,
+            commands::run_chartread,
+            commands::run_colprof,
+            commands::run_profcheck,
+            settings::load_settings,
+            settings::save_settings,
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");
diff --git a/src-tauri/src/process_manager.rs b/src-tauri/src/process_manager.rs
index 2c8ae27..eb8d715 100644
--- a/src-tauri/src/process_manager.rs
+++ b/src-tauri/src/process_manager.rs
@@ -38,9 +38,15 @@ impl ProcessManager {
                 let id_clone = id.clone();
                 let app_clone = app.clone();
                 tokio::spawn(async move {
+                    const JSON_ROW_PREFIX: &str = "ROW_COLORS_JSON: ";
                     let mut reader = BufReader::new(stdout).lines();
                     while let Ok(Some(line)) = reader.next_line().await {
-                        emit_stdout(&app_clone, &id_clone, line);
+                        if line.starts_with(JSON_ROW_PREFIX) {
+                            let json_str = line[JSON_ROW_PREFIX.len()..].to_string();
+                            crate::events::emit_json_row(&app_clone, &id_clone, json_str);
+                        } else {
+                            emit_stdout(&app_clone, &id_clone, line);
+                        }
                     }
                 });
 
diff --git a/src-tauri/src/settings.rs b/src-tauri/src/settings.rs
new file mode 100644
index 0000000..974d911
--- /dev/null
+++ b/src-tauri/src/settings.rs
@@ -0,0 +1,27 @@
+use serde::{Deserialize, Serialize};
+use std::fs;
+use tauri::{AppHandle, Manager};
+
+#[derive(Debug, Deserialize, Serialize, Default, Clone)]
+pub struct AppSettings {
+    pub argyll_binary_dir: Option<String>,
+    pub default_instrument: Option<String>,
+}
+
+#[tauri::command]
+pub fn load_settings(app: AppHandle) -> Result<AppSettings, String> {
+    let path = app.path().app_data_dir().unwrap().join("settings.json");
+    if let Ok(data) = fs::read_to_string(path) {
+        Ok(serde_json::from_str(&data).unwrap_or_default())
+    } else {
+        Ok(AppSettings::default())
+    }
+}
+
+#[tauri::command]
+pub fn save_settings(app: AppHandle, settings: AppSettings) -> Result<(), String> {
+    let path = app.path().app_data_dir().unwrap();
+    fs::create_dir_all(&path).map_err(|e| e.to_string())?;
+    let json = serde_json::to_string_pretty(&settings).unwrap();
+    fs::write(path.join("settings.json"), json).map_err(|e| e.to_string())
+}
diff --git a/src/index.html b/src/index.html
index c2aae67..0d394f9 100644
--- a/src/index.html
+++ b/src/index.html
@@ -5,6 +5,9 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>ICCery</title>
     <link rel="stylesheet" href="./styles/main.css" />
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
+    <script src="https://cdn.jsdelivr.net/npm/three@0.128.0/examples/js/controls/OrbitControls.js"></script>
+    <script src="./js/delaunator.min.js"></script>
     <script type="module" src="./js/app.js" defer></script>
   </head>
   <body>
@@ -12,6 +15,7 @@
       <aside class="sidebar">
         <div class="brand">
           <h1>ICCery</h1>
+          <button id="openSettingsBtn" class="icon-btn" title="Settings">⚙️</button>
         </div>
         <nav class="stepper">
           <button class="step active" data-step="1">1. Generate Target</button>
@@ -84,32 +88,262 @@
         <!-- Stage 2: printtarg -->
         <section id="stage-2" class="stage hidden">
           <h2>Print Layout</h2>
-          <p>Prepare the target for printing based on your instrument.</p>
-          <button class="primary" id="btnLayout">Create Layout (.ti2, .tif)</button>
+          <p>Configure the target layout for your instrument and paper size, then generate printable TIFF images.</p>
+
+          <!-- Colour management warning banner -->
+          <div class="warning-banner" id="cmWarningBanner">
+            <span class="warning-icon">⚠️</span>
+            <div class="warning-text">
+              <strong>CRITICAL: Disable ALL printer driver colour management when printing these targets.</strong>
+              <p>Set your printer driver to "No Colour Adjustment" (Epson), "Off (No Colour Adjustment)" (Canon), or the equivalent setting for your printer. Failure to do this will produce an incorrect profile.</p>
+            </div>
+          </div>
+
+          <div class="form-container">
+            <div class="form-group">
+              <label>Measurement Instrument</label>
+              <select id="instrumentSelect">
+                <option value="i1" selected>X-Rite i1Pro / i1Pro2</option>
+                <option value="p3">X-Rite i1Pro3+</option>
+                <option value="CM">X-Rite ColorMunki</option>
+                <option value="SS">X-Rite SpectroScan</option>
+                <option value="20">X-Rite DTP20</option>
+                <option value="22">X-Rite DTP22</option>
+                <option value="41">X-Rite DTP41</option>
+                <option value="51">X-Rite DTP51</option>
+              </select>
+            </div>
+
+            <div class="form-group">
+              <label>Page Size</label>
+              <select id="pageSizeSelect">
+                <option value="A4" selected>A4 [210 × 297 mm]</option>
+                <option value="A4R">A4 Landscape [297 × 210 mm]</option>
+                <option value="A3">A3 [297 × 420 mm]</option>
+                <option value="A2">A2 [420 × 594 mm]</option>
+                <option value="Letter">US Letter [215.9 × 279.4 mm]</option>
+                <option value="LetterR">US Letter Landscape [279.4 × 215.9 mm]</option>
+                <option value="Legal">US Legal [215.9 × 355.6 mm]</option>
+                <option value="4x6">4×6 [101.6 × 152.4 mm]</option>
+                <option value="11x17">11×17 [279.4 × 431.8 mm]</option>
+                <option value="custom">Custom...</option>
+              </select>
+              <div id="customPageSizeRow" class="input-row hidden" style="margin-top: 8px;">
+                <div>
+                  <label for="customPageW" class="sub-label">Width (mm)</label>
+                  <input type="number" id="customPageW" min="50" max="2000" placeholder="e.g. 200">
+                </div>
+                <div>
+                  <label for="customPageH" class="sub-label">Height (mm)</label>
+                  <input type="number" id="customPageH" min="50" max="2000" placeholder="e.g. 400">
+                </div>
+              </div>
+            </div>
+
+            <div class="form-group">
+              <label>TIFF Output</label>
+              <div class="input-row">
+                <div>
+                  <label class="sub-label">Bit Depth</label>
+                  <div class="radio-group">
+                    <label><input type="radio" name="bitDepth" value="8" checked> 8-bit</label>
+                    <label><input type="radio" name="bitDepth" value="16"> 16-bit</label>
+                  </div>
+                </div>
+                <div>
+                  <label for="tiffDpi" class="sub-label">Resolution (DPI)</label>
+                  <select id="tiffDpi">
+                    <option value="100">100 DPI (Draft)</option>
+                    <option value="200" selected>200 DPI (Standard)</option>
+                    <option value="300">300 DPI (High Quality)</option>
+                    <option value="600">600 DPI (Ultra)</option>
+                  </select>
+                </div>
+              </div>
+            </div>
+          </div>
+
+          <button class="primary" id="btnCreateLayout">Create Layout (.ti2 + .tif)</button>
+
+          <div class="log-container hidden" id="printtargLogContainer">
+            <h4>Process Output</h4>
+            <pre id="printtargLog"></pre>
+          </div>
+
+          <!-- TIFF preview gallery (populated dynamically after generation) -->
+          <div class="tiff-gallery hidden" id="tiffGallery">
+            <h3>Generated Target Pages</h3>
+            <div class="gallery-info" id="galleryInfo"></div>
+            <div class="gallery-grid" id="galleryGrid"></div>
+          </div>
         </section>
 
         <!-- Stage 3: chartread -->
         <section id="stage-3" class="stage hidden">
           <h2>Measure Target</h2>
-          <p>Read the printed patches with your instrument.</p>
+          <p>Read the printed target patches with your spectrophotometer.</p>
+
+          <!-- State & Prompt Area -->
+          <div class="chartread-status">
+            <div class="status-label">State: <span id="chartreadState">IDLE</span></div>
+            <div class="status-prompt" id="chartreadPrompt">
+              Press 'Start Measurement' to begin reading the printed target.
+            </div>
+          </div>
+
+          <!-- Action Buttons -->
+          <div class="chartread-actions">
+            <button class="primary" id="btnStartRead">Start Measurement</button>
+            <button class="primary hidden" id="btnCalibrate">✓ Calibrate</button>
+            <button class="secondary hidden" id="btnRetry">↻ Retry Strip</button>
+            <button class="secondary hidden" id="btnSkip">⏭ Skip Strip</button>
+            <button class="danger hidden" id="btnCancel">✕ Cancel</button>
+          </div>
+
+          <!-- Progress Bar -->
+          <div class="read-progress-container hidden" id="readProgressContainer">
+            <div class="read-progress-bar" id="readProgress" style="width: 0%"></div>
+          </div>
+          <div class="read-progress-text" id="readProgressText"></div>
+
+          <!-- Live Stats -->
+          <div class="read-stats" id="readStats"></div>
+
+          <!-- Swatch Grid -->
           <div class="swatch-grid" id="swatchGrid"></div>
-          <button class="primary" id="btnRead">Start Reading (.ti3)</button>
+
+          <!-- Process Log -->
+          <div class="log-container hidden" id="chartreadLogContainer">
+            <h4>Process Output</h4>
+            <pre id="chartreadLog"></pre>
+          </div>
         </section>
 
         <!-- Stage 4: colprof -->
         <section id="stage-4" class="stage hidden">
           <h2>Create Profile</h2>
-          <p>Calculate the ICC profile.</p>
-          <button class="primary" id="btnProfile">Create Profile (.icc)</button>
+          <p>Calculate the ICC profile from your target measurement data.</p>
+
+          <div class="form-container">
+            <div class="form-group">
+              <label>Profile Quality</label>
+              <select id="colprofQuality">
+                <option value="l">Low (Fast draft)</option>
+                <option value="m" selected>Medium (Standard)</option>
+                <option value="h">High (Recommended)</option>
+                <option value="u">Ultra (Maximum precision - slow)</option>
+              </select>
+            </div>
+
+            <div class="form-group">
+              <label>Profile Description</label>
+              <input type="text" id="colprofDescription" placeholder="e.g. Epson P600 Lustre Photo">
+            </div>
+
+            <div class="form-group">
+              <label>Copyright / Creator (Optional)</label>
+              <input type="text" id="colprofCopyright" placeholder="e.g. Copyright (c) 2026 My Studio">
+            </div>
+
+            <div class="form-group">
+              <label>Algorithm Type</label>
+              <select id="colprofAlgorithm">
+                <option value="l" selected>Lab cLUT (Standard Lookup Table)</option>
+                <option value="x">XYZ cLUT</option>
+                <option value="X">Display XYZ cLUT + Matrix</option>
+                <option value="m">Matrix Only (Simple)</option>
+              </select>
+            </div>
+          </div>
+
+          <button class="primary" id="btnCreateProfile">Calculate Profile (.icc)</button>
+
+          <!-- Spinner and Progress Stage -->
+          <div class="spinner-container hidden" id="colprofSpinnerContainer">
+            <div class="spinner"></div>
+            <div class="stage-label" id="colprofStageLabel">Calculating ICC Profile...</div>
+          </div>
+
+          <!-- Success Card -->
+          <div class="success-card hidden" id="colprofSuccessCard">
+            <h3>🎉 Profile Calculation Complete</h3>
+            <p id="colprofSuccessInfo"></p>
+            <button class="primary" id="btnGoToVerify">Proceed to Verification →</button>
+          </div>
+
+          <!-- Process Log -->
+          <div class="log-container hidden" id="colprofLogContainer">
+            <h4>Process Output</h4>
+            <pre id="colprofLog"></pre>
+          </div>
         </section>
 
         <!-- Stage 5: profcheck -->
         <section id="stage-5" class="stage hidden">
-          <h2>Verify</h2>
-          <p>Analyze the generated profile quality.</p>
-          <button class="primary" id="btnVerify">Verify Profile</button>
+          <h2>Verify Profile</h2>
+          <p>Check the numerical accuracy of your profile against the original measurement data.</p>
+
+          <button class="primary" id="btnVerify">Run Profile Verification</button>
+
+          <!-- Report Card -->
+          <div class="report-card hidden" id="profcheckReportCard">
+            <div class="report-header">
+              <h3>Profile Quality Report</h3>
+              <div id="profcheckBadge" class="report-badge">GOOD</div>
+            </div>
+            
+            <div class="report-metrics">
+              <div class="metric-box">
+                <span class="metric-value" id="profcheckAvgDe">0.00</span>
+                <span class="metric-label">Average ΔE₀₀</span>
+              </div>
+              <div class="metric-box">
+                <span class="metric-value" id="profcheckMaxDe">0.00</span>
+                <span class="metric-label">Peak ΔE₀₀</span>
+              </div>
+              <div class="metric-box">
+                <span class="metric-value" id="profcheckRmsDe">0.00</span>
+                <span class="metric-label">RMS ΔE₀₀</span>
+              </div>
+            </div>
+
+            <div class="report-footnote">
+              Professional printer profiles typically achieve average ΔE₀₀ &lt; 1.0, and acceptable profiles &lt; 2.0.
+            </div>
+          </div>
+
+          <!-- 3D Gamut Viewer -->
+          <div class="gamut-viewer-section">
+            <h3>3D Gamut Visualization (CIELAB)</h3>
+            <div id="gamutViewerContainer"></div>
+          </div>
+
+          <!-- Process Log -->
+          <div class="log-container hidden" id="profcheckLogContainer">
+            <h4>Verification Output</h4>
+            <pre id="profcheckLog"></pre>
+          </div>
         </section>
       </main>
     </div>
+
+    <!-- Settings Dialog -->
+    <dialog id="settingsDialog" class="settings-modal">
+      <div class="modal-content">
+        <h2>Application Settings</h2>
+        <div class="form-group">
+          <label for="argyll_binary_dir">ArgyllCMS Binary Directory Override</label>
+          <input type="text" id="argyll_binary_dir" placeholder="Leave empty for bundled sidecars (e.g. /usr/bin)">
+        </div>
+        <div class="form-group">
+          <label for="default_instrument">Default Instrument Override</label>
+          <input type="text" id="default_instrument" placeholder="e.g. i1">
+        </div>
+        <div class="modal-actions">
+          <button id="saveSettingsBtn" class="primary">Save Settings</button>
+          <button id="closeSettingsBtn" class="secondary">Cancel</button>
+        </div>
+      </div>
+    </dialog>
   </body>
 </html>
diff --git a/src/js/app.js b/src/js/app.js
index c9d7f1b..19eaf5a 100644
--- a/src/js/app.js
+++ b/src/js/app.js
@@ -1,4 +1,10 @@
 import { initTargen } from './targen.js';
+import { initPrinttarg } from './printtarg.js';
+import { initChartread } from './chartread.js';
+import { initColprof } from './colprof.js';
+import { initProfcheck } from './profcheck.js';
+import { initSettings } from './settings.js';
+import { initGamutViewer } from './gamut_viewer.js';
 
 const { invoke } = window.__TAURI__.core;
 
@@ -20,11 +26,27 @@ document.addEventListener('DOMContentLoaded', () => {
       
       step.classList.add('active');
       const targetStage = document.getElementById(`stage-${targetStep}`);
-      targetStage.classList.remove('hidden');
-      targetStage.classList.add('active');
+      if (targetStage) {
+        targetStage.classList.remove('hidden');
+        targetStage.classList.add('active');
+      }
     });
   });
 
-  // Initialize Stage 1
-  initTargen();
+  const safeInit = (name, initFn) => {
+    try {
+      initFn();
+    } catch (e) {
+      console.error(`[ICCery Init Error] Failed to initialize ${name}:`, e);
+    }
+  };
+
+  // Initialize all stages & features safely
+  safeInit('Stage 1 (Targen)', initTargen);
+  safeInit('Stage 2 (Printtarg)', initPrinttarg);
+  safeInit('Stage 3 (Chartread)', initChartread);
+  safeInit('Stage 4 (Colprof)', initColprof);
+  safeInit('Stage 5 (Profcheck)', initProfcheck);
+  safeInit('Settings', initSettings);
+  safeInit('Gamut Viewer', initGamutViewer);
 });
diff --git a/src/js/chartread.js b/src/js/chartread.js
new file mode 100644
index 0000000..b6c69f6
--- /dev/null
+++ b/src/js/chartread.js
@@ -0,0 +1,235 @@
+const { invoke } = window.__TAURI__.core;
+const { listen } = window.__TAURI__.event;
+import { startSwatchListener, stopSwatchListener } from './swatch_grid.js';
+import { setStage3Result } from './colprof.js';
+
+// Module-level state: set by Stage 2 when it completes
+let stage2Basename = "";
+let stage2Cwd = "";
+
+/**
+ * Called by printtarg.js after Stage 2 completes.
+ */
+export function setStage2Result(basename, cwd) {
+  stage2Basename = basename;
+  stage2Cwd = cwd;
+}
+
+// State machine states
+const STATE = {
+  IDLE: "IDLE",
+  CALIBRATING: "CALIBRATING",
+  AWAITING_STRIP: "AWAITING_STRIP",
+  READING: "READING",
+  ERROR: "ERROR",
+  FINISHED: "FINISHED",
+};
+
+let currentState = STATE.IDLE;
+let currentProcessId = "";
+
+export function initChartread() {
+  const btnStartRead = document.getElementById("btnStartRead");
+  const btnCalibrate = document.getElementById("btnCalibrate");
+  const btnRetry = document.getElementById("btnRetry");
+  const btnSkip = document.getElementById("btnSkip");
+  const btnCancel = document.getElementById("btnCancel");
+  const promptText = document.getElementById("chartreadPrompt");
+  const stateLabel = document.getElementById("chartreadState");
+  const logContainer = document.getElementById("chartreadLogContainer");
+  const logPre = document.getElementById("chartreadLog");
+
+  function setState(newState) {
+    currentState = newState;
+    if (stateLabel) stateLabel.textContent = newState;
+
+    // Show/hide buttons based on state
+    btnCalibrate.classList.add("hidden");
+    btnRetry.classList.add("hidden");
+    btnSkip.classList.add("hidden");
+    btnCancel.classList.add("hidden");
+    btnStartRead.classList.add("hidden");
+
+    switch (newState) {
+      case STATE.IDLE:
+        btnStartRead.classList.remove("hidden");
+        break;
+      case STATE.CALIBRATING:
+        btnCalibrate.classList.remove("hidden");
+        btnCancel.classList.remove("hidden");
+        break;
+      case STATE.AWAITING_STRIP:
+        btnRetry.classList.remove("hidden");
+        btnSkip.classList.remove("hidden");
+        btnCancel.classList.remove("hidden");
+        break;
+      case STATE.READING:
+        btnCancel.classList.remove("hidden");
+        break;
+      case STATE.ERROR:
+        btnRetry.classList.remove("hidden");
+        btnSkip.classList.remove("hidden");
+        btnCancel.classList.remove("hidden");
+        break;
+      case STATE.FINISHED:
+        btnStartRead.classList.remove("hidden");
+        break;
+    }
+  }
+
+  function setPrompt(text) {
+    if (promptText) promptText.textContent = text;
+  }
+
+  // Start reading button
+  if (btnStartRead) {
+    btnStartRead.addEventListener("click", async () => {
+      if (!stage2Basename) {
+        setPrompt("Error: No .ti2 file available. Complete Stage 2 first.");
+        return;
+      }
+
+      logPre.textContent = "";
+      logContainer.classList.remove("hidden");
+      setState(STATE.CALIBRATING);
+      setPrompt("Starting chartread... waiting for instrument calibration prompt.");
+
+      const config = {
+        basename: stage2Basename,
+        cwd: stage2Cwd,
+      };
+
+      currentProcessId = `chartread_${stage2Basename}`;
+
+      // Start swatch grid listener
+      await startSwatchListener(currentProcessId);
+
+      try {
+        const unlistenStdout = await listen("process:stdout", (event) => {
+          if (event.payload.id !== currentProcessId || !event.payload.line) return;
+          const line = event.payload.line;
+
+          logPre.textContent += line + "\n";
+          logPre.scrollTop = logPre.scrollHeight;
+
+          // Parse prompts for state transitions
+          const lineLower = line.toLowerCase();
+
+          if (lineLower.includes("calibrat") && lineLower.includes("place")) {
+            setState(STATE.CALIBRATING);
+            setPrompt(line);
+          } else if (lineLower.includes("hit") && lineLower.includes("read") && lineLower.includes("strip")) {
+            setState(STATE.AWAITING_STRIP);
+            setPrompt(line);
+          } else if (lineLower.includes("ready to read")) {
+            setState(STATE.AWAITING_STRIP);
+            setPrompt(line);
+          } else if (lineLower.includes("reading strip") || lineLower.includes("processing")) {
+            setState(STATE.READING);
+            setPrompt(line);
+          } else if (lineLower.includes("error") || lineLower.includes("too fast") || lineLower.includes("too slow") || lineLower.includes("misread")) {
+            setState(STATE.ERROR);
+            setPrompt("⚠️ " + line);
+          }
+        });
+
+        const unlistenStderr = await listen("process:stderr", (event) => {
+          if (event.payload.id === currentProcessId && event.payload.line) {
+            logPre.textContent += "ERR: " + event.payload.line + "\n";
+            logPre.scrollTop = logPre.scrollHeight;
+          }
+        });
+
+        const unlistenExit = await listen("process:exit", (event) => {
+          if (event.payload.id !== currentProcessId) return;
+          unlistenStdout();
+          unlistenStderr();
+          unlistenExit();
+          stopSwatchListener();
+
+          if (event.payload.code === 0) {
+            setState(STATE.FINISHED);
+            setPrompt("✅ Measurement complete! .ti3 file has been saved.");
+            logPre.textContent += "\n[SUCCESS] chartread completed. .ti3 file written.\n";
+            setStage3Result(stage2Basename, stage2Cwd);
+            advanceToStage4();
+          } else {
+            setState(STATE.FINISHED);
+            setPrompt(`❌ chartread exited with code ${event.payload.code}.`);
+            logPre.textContent += `\n[ERROR] chartread exited with code ${event.payload.code}.\n`;
+          }
+        });
+
+        await invoke("run_chartread", { config });
+
+      } catch (err) {
+        setPrompt(`Invoke error: ${err}`);
+        setState(STATE.IDLE);
+      }
+    });
+  }
+
+  // Calibrate / confirm button — sends space + newline
+  if (btnCalibrate) {
+    btnCalibrate.addEventListener("click", async () => {
+      try {
+        await invoke("send_stdin", { id: currentProcessId, input: " \n" });
+      } catch (e) { console.error("send_stdin error:", e); }
+    });
+  }
+
+  // Retry button — sends space + newline (same as confirm)
+  if (btnRetry) {
+    btnRetry.addEventListener("click", async () => {
+      try {
+        await invoke("send_stdin", { id: currentProcessId, input: " \n" });
+        setState(STATE.READING);
+        setPrompt("Retrying strip read...");
+      } catch (e) { console.error("send_stdin error:", e); }
+    });
+  }
+
+  // Skip button — sends "s\n"
+  if (btnSkip) {
+    btnSkip.addEventListener("click", async () => {
+      try {
+        await invoke("send_stdin", { id: currentProcessId, input: "s\n" });
+        setState(STATE.AWAITING_STRIP);
+        setPrompt("Skipped current strip. Awaiting next...");
+      } catch (e) { console.error("send_stdin error:", e); }
+    });
+  }
+
+  // Cancel button — kills the process
+  if (btnCancel) {
+    btnCancel.addEventListener("click", async () => {
+      try {
+        await invoke("kill_process", { id: currentProcessId });
+        stopSwatchListener();
+        setState(STATE.IDLE);
+        setPrompt("Measurement cancelled.");
+      } catch (e) { console.error("kill_process error:", e); }
+    });
+  }
+
+  // Start in IDLE state
+  setState(STATE.IDLE);
+  setPrompt("Press 'Start Measurement' to begin reading the printed target.");
+}
+
+function advanceToStage4() {
+  const steps = document.querySelectorAll('.step');
+  const stages = document.querySelectorAll('.stage');
+
+  steps.forEach(s => s.classList.remove('active'));
+  if (steps[3]) steps[3].classList.add('active');
+
+  stages.forEach(s => {
+    s.classList.remove('active');
+    s.classList.add('hidden');
+  });
+  if (stages[3]) {
+    stages[3].classList.remove('hidden');
+    stages[3].classList.add('active');
+  }
+}
diff --git a/src/js/color_convert.js b/src/js/color_convert.js
new file mode 100644
index 0000000..8428e78
--- /dev/null
+++ b/src/js/color_convert.js
@@ -0,0 +1,67 @@
+/**
+ * Convert CIE L*a*b* to sRGB [0–255] clamped values.
+ * Uses D50 illuminant reference white (standard for ICC profiles).
+ * @param {number} L - Lightness [0, 100]
+ * @param {number} a - Green-red axis [-128, 127]
+ * @param {number} b - Blue-yellow axis [-128, 127]
+ * @returns {number[]} [r, g, b] each in [0, 255]
+ */
+export function labToSrgb(L, a, b) {
+  // D50 reference white
+  const Xn = 0.9642;
+  const Yn = 1.0;
+  const Zn = 0.8249;
+
+  // Lab → XYZ
+  const fy = (L + 16) / 116;
+  const fx = a / 500 + fy;
+  const fz = fy - b / 200;
+
+  const delta = 6 / 29;
+  const delta3 = delta * delta * delta;
+
+  const X = Xn * (fx > delta ? fx * fx * fx : (fx - 16 / 116) * 3 * delta * delta);
+  const Y = Yn * (fy > delta ? fy * fy * fy : (fy - 16 / 116) * 3 * delta * delta);
+  const Z = Zn * (fz > delta ? fz * fz * fz : (fz - 16 / 116) * 3 * delta * delta);
+
+  // XYZ (D50) → linear sRGB via Bradford-adapted D50→D65 matrix
+  // Combined D50-adapted XYZ to sRGB matrix
+  const lr =  3.1338561 * X - 1.6168667 * Y - 0.4906146 * Z;
+  const lg = -0.9787684 * X + 1.9161415 * Y + 0.0334540 * Z;
+  const lb =  0.0719453 * X - 0.2289914 * Y + 1.4052427 * Z;
+
+  // Linear sRGB → gamma-corrected sRGB
+  function gammaCorrect(c) {
+    return c <= 0.0031308
+      ? 12.92 * c
+      : 1.055 * Math.pow(c, 1 / 2.4) - 0.055;
+  }
+
+  const r = Math.round(Math.max(0, Math.min(255, gammaCorrect(lr) * 255)));
+  const g = Math.round(Math.max(0, Math.min(255, gammaCorrect(lg) * 255)));
+  const bVal = Math.round(Math.max(0, Math.min(255, gammaCorrect(lb) * 255)));
+
+  return [r, g, bVal];
+}
+
+/**
+ * Convert device RGB percentages [0–100] to CSS rgb string.
+ * @param {number[]} device - [R%, G%, B%] each in [0, 100]
+ * @returns {string} CSS rgb() string
+ */
+export function deviceRgbToCss(device) {
+  const r = Math.round((device[0] / 100) * 255);
+  const g = Math.round((device[1] / 100) * 255);
+  const b = Math.round((device[2] / 100) * 255);
+  return `rgb(${r}, ${g}, ${b})`;
+}
+
+/**
+ * Convert Lab triplet to CSS rgb string.
+ * @param {number[]} lab - [L, a, b]
+ * @returns {string} CSS rgb() string
+ */
+export function labToCss(lab) {
+  const [r, g, b] = labToSrgb(lab[0], lab[1], lab[2]);
+  return `rgb(${r}, ${g}, ${b})`;
+}
diff --git a/src/js/colprof.js b/src/js/colprof.js
new file mode 100644
index 0000000..2a7f8c0
--- /dev/null
+++ b/src/js/colprof.js
@@ -0,0 +1,133 @@
+const { invoke } = window.__TAURI__.core;
+const { listen } = window.__TAURI__.event;
+import { setStage4Result } from './profcheck.js';
+
+let chartreadBasename = "";
+let chartreadCwd = "";
+
+/**
+ * Called by chartread.js after Stage 3 completes.
+ */
+export function setStage3Result(basename, cwd) {
+  chartreadBasename = basename;
+  chartreadCwd = cwd;
+}
+
+export function initColprof() {
+  const qualitySelect = document.getElementById("colprofQuality");
+  const algorithmSelect = document.getElementById("colprofAlgorithm");
+  const descInput = document.getElementById("colprofDescription");
+  const copyrightInput = document.getElementById("colprofCopyright");
+  const btnCreateProfile = document.getElementById("btnCreateProfile");
+  const spinnerContainer = document.getElementById("colprofSpinnerContainer");
+  const stageLabel = document.getElementById("colprofStageLabel");
+  const logContainer = document.getElementById("colprofLogContainer");
+  const logPre = document.getElementById("colprofLog");
+  const successCard = document.getElementById("colprofSuccessCard");
+  const successInfo = document.getElementById("colprofSuccessInfo");
+  const btnGoToVerify = document.getElementById("btnGoToVerify");
+
+  if (!btnCreateProfile) return;
+
+  btnCreateProfile.addEventListener("click", async () => {
+    const basename = chartreadBasename || "test_target";
+    const cwd = chartreadCwd || "";
+
+    const description = descInput.value.trim() || basename;
+
+    logPre.textContent = "";
+    logContainer.classList.remove("hidden");
+    spinnerContainer.classList.remove("hidden");
+    successCard.classList.add("hidden");
+    btnCreateProfile.disabled = true;
+    stageLabel.textContent = "Initializing colprof...";
+
+    const config = {
+      quality: qualitySelect.value,
+      algorithm: algorithmSelect.value,
+      description: description,
+      copyright: copyrightInput.value.trim() || null,
+      basename: basename,
+      cwd: cwd,
+    };
+
+    const processId = `colprof_${basename}`;
+
+    try {
+      const unlistenStdout = await listen("process:stdout", (event) => {
+        if (event.payload.id === processId && event.payload.line) {
+          const line = event.payload.line;
+          logPre.textContent += line + "\n";
+          logPre.scrollTop = logPre.scrollHeight;
+
+          // Parse coarse progress stages from stdout
+          const lineLower = line.toLowerCase();
+          if (lineLower.includes("gamut mapping")) {
+            stageLabel.textContent = "Gamut mapping calculation in progress...";
+          } else if (lineLower.includes("fitting") || lineLower.includes("clut")) {
+            stageLabel.textContent = "Fitting cLUT grid points...";
+          } else if (lineLower.includes("writing") || lineLower.includes("icc profile")) {
+            stageLabel.textContent = "Writing ICC profile header & tags...";
+          }
+        }
+      });
+
+      const unlistenStderr = await listen("process:stderr", (event) => {
+        if (event.payload.id === processId && event.payload.line) {
+          logPre.textContent += "ERR: " + event.payload.line + "\n";
+          logPre.scrollTop = logPre.scrollHeight;
+        }
+      });
+
+      const unlistenExit = await listen("process:exit", (event) => {
+        if (event.payload.id === processId) {
+          unlistenStdout();
+          unlistenStderr();
+          unlistenExit();
+          spinnerContainer.classList.add("hidden");
+          btnCreateProfile.disabled = false;
+
+          if (event.payload.code === 0) {
+            logPre.textContent += "\n[SUCCESS] colprof completed. Profile generated.\n";
+            const iccFilename = `${basename}.icc`;
+            successInfo.textContent = `Profile: ${iccFilename} (${description})`;
+            successCard.classList.remove("hidden");
+
+            setStage4Result(basename, cwd);
+          } else {
+            logPre.textContent += `\n[ERROR] colprof exited with code ${event.payload.code}.\n`;
+          }
+        }
+      });
+
+      await invoke("run_colprof", { config });
+    } catch (err) {
+      logPre.textContent += `\n[INVOKE ERROR] ${err}\n`;
+      spinnerContainer.classList.add("hidden");
+      btnCreateProfile.disabled = false;
+    }
+  });
+
+  if (btnGoToVerify) {
+    btnGoToVerify.addEventListener("click", () => {
+      advanceToStage5();
+    });
+  }
+}
+
+function advanceToStage5() {
+  const steps = document.querySelectorAll('.step');
+  const stages = document.querySelectorAll('.stage');
+
+  steps.forEach(s => s.classList.remove('active'));
+  if (steps[4]) steps[4].classList.add('active');
+
+  stages.forEach(s => {
+    s.classList.remove('active');
+    s.classList.add('hidden');
+  });
+  if (stages[4]) {
+    stages[4].classList.remove('hidden');
+    stages[4].classList.add('active');
+  }
+}
diff --git a/src/js/delaunator.min.js b/src/js/delaunator.min.js
new file mode 100644
index 0000000..1f63da5
--- /dev/null
+++ b/src/js/delaunator.min.js
@@ -0,0 +1 @@
+!function(t,i){"object"==typeof exports&&"undefined"!=typeof module?module.exports=i():"function"==typeof define&&define.amd?define(i):(t="undefined"!=typeof globalThis?globalThis:t||self).Delaunator=i()}(this,(function(){"use strict";const t=134217729;function i(t,i,s,e,n){let h,r,l,o,a=i[0],f=e[0],c=0,u=0;f>a==f>-a?(h=a,a=i[++c]):(h=f,f=e[++u]);let _=0;if(c<t&&u<s)for(f>a==f>-a?(r=a+h,l=h-(r-a),a=i[++c]):(r=f+h,l=h-(r-f),f=e[++u]),h=r,0!==l&&(n[_++]=l);c<t&&u<s;)f>a==f>-a?(r=h+a,o=r-h,l=h-(r-o)+(a-o),a=i[++c]):(r=h+f,o=r-h,l=h-(r-o)+(f-o),f=e[++u]),h=r,0!==l&&(n[_++]=l);for(;c<t;)r=h+a,o=r-h,l=h-(r-o)+(a-o),a=i[++c],h=r,0!==l&&(n[_++]=l);for(;u<s;)r=h+f,o=r-h,l=h-(r-o)+(f-o),f=e[++u],h=r,0!==l&&(n[_++]=l);return 0===h&&0!==_||(n[_++]=h),_}function s(t){return new Float64Array(t)}const e=s(4),n=s(8),h=s(12),r=s(16),l=s(4);function o(s,o,a,f,c,u){const _=(o-u)*(a-c),d=(s-c)*(f-u),g=_-d;if(0===_||0===d||_>0!=d>0)return g;const y=Math.abs(_+d);return Math.abs(g)>=33306690738754716e-32*y?g:-function(s,o,a,f,c,u,_){let d,g,y,w,b,A,k,M,p,x,S,T,z,U,m,K,L,v;const F=s-c,P=a-c,E=o-u,H=f-u;U=F*H,A=t*F,k=A-(A-F),M=F-k,A=t*H,p=A-(A-H),x=H-p,m=M*x-(U-k*p-M*p-k*x),K=E*P,A=t*E,k=A-(A-E),M=E-k,A=t*P,p=A-(A-P),x=P-p,L=M*x-(K-k*p-M*p-k*x),S=m-L,b=m-S,e[0]=m-(S+b)+(b-L),T=U+S,b=T-U,z=U-(T-b)+(S-b),S=z-K,b=z-S,e[1]=z-(S+b)+(b-K),v=T+S,b=v-T,e[2]=T-(v-b)+(S-b),e[3]=v;let I=function(t,i){let s=i[0];for(let e=1;e<t;e++)s+=i[e];return s}(4,e),N=22204460492503146e-32*_;if(I>=N||-I>=N)return I;if(b=s-F,d=s-(F+b)+(b-c),b=a-P,y=a-(P+b)+(b-c),b=o-E,g=o-(E+b)+(b-u),b=f-H,w=f-(H+b)+(b-u),0===d&&0===g&&0===y&&0===w)return I;if(N=11093356479670487e-47*_+33306690738754706e-32*Math.abs(I),I+=F*w+H*d-(E*y+P*g),I>=N||-I>=N)return I;U=d*H,A=t*d,k=A-(A-d),M=d-k,A=t*H,p=A-(A-H),x=H-p,m=M*x-(U-k*p-M*p-k*x),K=g*P,A=t*g,k=A-(A-g),M=g-k,A=t*P,p=A-(A-P),x=P-p,L=M*x-(K-k*p-M*p-k*x),S=m-L,b=m-S,l[0]=m-(S+b)+(b-L),T=U+S,b=T-U,z=U-(T-b)+(S-b),S=z-K,b=z-S,l[1]=z-(S+b)+(b-K),v=T+S,b=v-T,l[2]=T-(v-b)+(S-b),l[3]=v;const j=i(4,e,4,l,n);U=F*w,A=t*F,k=A-(A-F),M=F-k,A=t*w,p=A-(A-w),x=w-p,m=M*x-(U-k*p-M*p-k*x),K=E*y,A=t*E,k=A-(A-E),M=E-k,A=t*y,p=A-(A-y),x=y-p,L=M*x-(K-k*p-M*p-k*x),S=m-L,b=m-S,l[0]=m-(S+b)+(b-L),T=U+S,b=T-U,z=U-(T-b)+(S-b),S=z-K,b=z-S,l[1]=z-(S+b)+(b-K),v=T+S,b=v-T,l[2]=T-(v-b)+(S-b),l[3]=v;const q=i(j,n,4,l,h);U=d*w,A=t*d,k=A-(A-d),M=d-k,A=t*w,p=A-(A-w),x=w-p,m=M*x-(U-k*p-M*p-k*x),K=g*y,A=t*g,k=A-(A-g),M=g-k,A=t*y,p=A-(A-y),x=y-p,L=M*x-(K-k*p-M*p-k*x),S=m-L,b=m-S,l[0]=m-(S+b)+(b-L),T=U+S,b=T-U,z=U-(T-b)+(S-b),S=z-K,b=z-S,l[1]=z-(S+b)+(b-K),v=T+S,b=v-T,l[2]=T-(v-b)+(S-b),l[3]=v;const D=i(q,h,4,l,r);return r[D-1]}(s,o,a,f,c,u,y)}const a=Math.pow(2,-52),f=new Uint32Array(512);class c{static from(t,i=w,s=b){const e=t.length,n=new Float64Array(2*e);for(let h=0;h<e;h++){const e=t[h];n[2*h]=i(e),n[2*h+1]=s(e)}return new c(n)}constructor(t){const i=t.length>>1;if(i>0&&"number"!=typeof t[0])throw new Error("Expected coords to contain numbers.");this.coords=t;const s=Math.max(2*i-5,0);this._triangles=new Uint32Array(3*s),this._halfedges=new Int32Array(3*s),this._hashSize=Math.ceil(Math.sqrt(i)),this._hullPrev=new Uint32Array(i),this._hullNext=new Uint32Array(i),this._hullTri=new Uint32Array(i),this._hullHash=new Int32Array(this._hashSize).fill(-1),this._ids=new Uint32Array(i),this._dists=new Float64Array(i),this.update()}update(){const{coords:t,_hullPrev:i,_hullNext:s,_hullTri:e,_hullHash:n}=this,h=t.length>>1;let r=1/0,l=1/0,f=-1/0,c=-1/0;for(let i=0;i<h;i++){const s=t[2*i],e=t[2*i+1];s<r&&(r=s),e<l&&(l=e),s>f&&(f=s),e>c&&(c=e),this._ids[i]=i}const _=(r+f)/2,y=(l+c)/2;let w,b,A,k=1/0;for(let i=0;i<h;i++){const s=u(_,y,t[2*i],t[2*i+1]);s<k&&(w=i,k=s)}const M=t[2*w],p=t[2*w+1];k=1/0;for(let i=0;i<h;i++){if(i===w)continue;const s=u(M,p,t[2*i],t[2*i+1]);s<k&&s>0&&(b=i,k=s)}let x=t[2*b],S=t[2*b+1],T=1/0;for(let i=0;i<h;i++){if(i===w||i===b)continue;const s=d(M,p,x,S,t[2*i],t[2*i+1]);s<T&&(A=i,T=s)}let z=t[2*A],U=t[2*A+1];if(T===1/0){for(let i=0;i<h;i++)this._dists[i]=t[2*i]-t[0]||t[2*i+1]-t[1];g(this._ids,this._dists,0,h-1);const i=new Uint32Array(h);let s=0;for(let t=0,e=-1/0;t<h;t++){const n=this._ids[t];this._dists[n]>e&&(i[s++]=n,e=this._dists[n])}return this.hull=i.subarray(0,s),this.triangles=new Uint32Array(0),void(this.halfedges=new Uint32Array(0))}if(o(M,p,x,S,z,U)<0){const t=b,i=x,s=S;b=A,x=z,S=U,A=t,z=i,U=s}const m=function(t,i,s,e,n,h){const r=s-t,l=e-i,o=n-t,a=h-i,f=r*r+l*l,c=o*o+a*a,u=.5/(r*a-l*o);return{x:t+(a*f-l*c)*u,y:i+(r*c-o*f)*u}}(M,p,x,S,z,U);this._cx=m.x,this._cy=m.y;for(let i=0;i<h;i++)this._dists[i]=u(t[2*i],t[2*i+1],m.x,m.y);g(this._ids,this._dists,0,h-1),this._hullStart=w;let K=3;s[w]=i[A]=b,s[b]=i[w]=A,s[A]=i[b]=w,e[w]=0,e[b]=1,e[A]=2,n.fill(-1),n[this._hashKey(M,p)]=w,n[this._hashKey(x,S)]=b,n[this._hashKey(z,U)]=A,this.trianglesLen=0,this._addTriangle(w,b,A,-1,-1,-1);for(let h,r,l=0;l<this._ids.length;l++){const f=this._ids[l],c=t[2*f],u=t[2*f+1];if(l>0&&Math.abs(c-h)<=a&&Math.abs(u-r)<=a)continue;if(h=c,r=u,f===w||f===b||f===A)continue;let _=0;for(let t=0,i=this._hashKey(c,u);t<this._hashSize&&(_=n[(i+t)%this._hashSize],-1===_||_===s[_]);t++);_=i[_];let d,g=_;for(;d=s[g],o(c,u,t[2*g],t[2*g+1],t[2*d],t[2*d+1])>=0;)if(g=d,g===_){g=-1;break}if(-1===g)continue;let y=this._addTriangle(g,f,s[g],-1,-1,e[g]);e[f]=this._legalize(y+2),e[g]=y,K++;let k=s[g];for(;d=s[k],o(c,u,t[2*k],t[2*k+1],t[2*d],t[2*d+1])<0;)y=this._addTriangle(k,f,d,e[f],-1,e[k]),e[f]=this._legalize(y+2),s[k]=k,K--,k=d;if(g===_)for(;d=i[g],o(c,u,t[2*d],t[2*d+1],t[2*g],t[2*g+1])<0;)y=this._addTriangle(d,f,g,-1,e[g],e[d]),this._legalize(y+2),e[d]=y,s[g]=g,K--,g=d;this._hullStart=i[f]=g,s[g]=i[k]=f,s[f]=k,n[this._hashKey(c,u)]=f,n[this._hashKey(t[2*g],t[2*g+1])]=g}this.hull=new Uint32Array(K);for(let t=0,i=this._hullStart;t<K;t++)this.hull[t]=i,i=s[i];this.triangles=this._triangles.subarray(0,this.trianglesLen),this.halfedges=this._halfedges.subarray(0,this.trianglesLen)}_hashKey(t,i){return Math.floor(function(t,i){const s=t/(Math.abs(t)+Math.abs(i));return(i>0?3-s:1+s)/4}(t-this._cx,i-this._cy)*this._hashSize)%this._hashSize}_legalize(t){const{_triangles:i,_halfedges:s,coords:e}=this;let n=0,h=0;for(;;){const r=s[t],l=t-t%3;if(h=l+(t+2)%3,-1===r){if(0===n)break;t=f[--n];continue}const o=r-r%3,a=l+(t+1)%3,c=o+(r+2)%3,u=i[h],d=i[t],g=i[a],y=i[c];if(_(e[2*u],e[2*u+1],e[2*d],e[2*d+1],e[2*g],e[2*g+1],e[2*y],e[2*y+1])){i[t]=y,i[r]=u;const e=s[c];if(-1===e){let i=this._hullStart;do{if(this._hullTri[i]===c){this._hullTri[i]=t;break}i=this._hullPrev[i]}while(i!==this._hullStart)}this._link(t,e),this._link(r,s[h]),this._link(h,c);const l=o+(r+1)%3;n<f.length&&(f[n++]=l)}else{if(0===n)break;t=f[--n]}}return h}_link(t,i){this._halfedges[t]=i,-1!==i&&(this._halfedges[i]=t)}_addTriangle(t,i,s,e,n,h){const r=this.trianglesLen;return this._triangles[r]=t,this._triangles[r+1]=i,this._triangles[r+2]=s,this._link(r,e),this._link(r+1,n),this._link(r+2,h),this.trianglesLen+=3,r}}function u(t,i,s,e){const n=t-s,h=i-e;return n*n+h*h}function _(t,i,s,e,n,h,r,l){const o=t-r,a=i-l,f=s-r,c=e-l,u=n-r,_=h-l,d=f*f+c*c,g=u*u+_*_;return o*(c*g-d*_)-a*(f*g-d*u)+(o*o+a*a)*(f*_-c*u)<0}function d(t,i,s,e,n,h){const r=s-t,l=e-i,o=n-t,a=h-i,f=r*r+l*l,c=o*o+a*a,u=.5/(r*a-l*o),_=(a*f-l*c)*u,d=(r*c-o*f)*u;return _*_+d*d}function g(t,i,s,e){if(e-s<=20)for(let n=s+1;n<=e;n++){const e=t[n],h=i[e];let r=n-1;for(;r>=s&&i[t[r]]>h;)t[r+1]=t[r--];t[r+1]=e}else{let n=s+1,h=e;y(t,s+e>>1,n),i[t[s]]>i[t[e]]&&y(t,s,e),i[t[n]]>i[t[e]]&&y(t,n,e),i[t[s]]>i[t[n]]&&y(t,s,n);const r=t[n],l=i[r];for(;;){do{n++}while(i[t[n]]<l);do{h--}while(i[t[h]]>l);if(h<n)break;y(t,n,h)}t[s+1]=t[h],t[h]=r,e-n+1>=h-s?(g(t,i,n,e),g(t,i,s,h-1)):(g(t,i,s,h-1),g(t,i,n,e))}}function y(t,i,s){const e=t[i];t[i]=t[s],t[s]=e}function w(t){return t[0]}function b(t){return t[1]}return c}));
diff --git a/src/js/delta_e.js b/src/js/delta_e.js
new file mode 100644
index 0000000..aef3749
--- /dev/null
+++ b/src/js/delta_e.js
@@ -0,0 +1,86 @@
+/**
+ * Compute CIEDE2000 colour difference (ΔE₀₀) between two L*a*b* values.
+ * Standard parametric factors: kL=1, kC=1, kH=1.
+ *
+ * Reference: Sharma, Wu, Dalal (2005) "The CIEDE2000 Color-Difference Formula"
+ *
+ * @param {number[]} lab1 - [L1, a1, b1]
+ * @param {number[]} lab2 - [L2, a2, b2]
+ * @returns {number} ΔE₀₀ value
+ */
+export function computeDeltaE00(lab1, lab2) {
+  const [L1, a1, b1] = lab1;
+  const [L2, a2, b2] = lab2;
+
+  const kL = 1, kC = 1, kH = 1;
+
+  const C1ab = Math.sqrt(a1 * a1 + b1 * b1);
+  const C2ab = Math.sqrt(a2 * a2 + b2 * b2);
+  const Cab_avg = (C1ab + C2ab) / 2;
+
+  const Cab_avg7 = Math.pow(Cab_avg, 7);
+  const G = 0.5 * (1 - Math.sqrt(Cab_avg7 / (Cab_avg7 + Math.pow(25, 7))));
+
+  const a1p = a1 * (1 + G);
+  const a2p = a2 * (1 + G);
+
+  const C1p = Math.sqrt(a1p * a1p + b1 * b1);
+  const C2p = Math.sqrt(a2p * a2p + b2 * b2);
+
+  let h1p = Math.atan2(b1, a1p) * (180 / Math.PI);
+  if (h1p < 0) h1p += 360;
+  let h2p = Math.atan2(b2, a2p) * (180 / Math.PI);
+  if (h2p < 0) h2p += 360;
+
+  const dLp = L2 - L1;
+  const dCp = C2p - C1p;
+
+  let dhp;
+  if (C1p * C2p === 0) {
+    dhp = 0;
+  } else if (Math.abs(h2p - h1p) <= 180) {
+    dhp = h2p - h1p;
+  } else if (h2p - h1p > 180) {
+    dhp = h2p - h1p - 360;
+  } else {
+    dhp = h2p - h1p + 360;
+  }
+  const dHp = 2 * Math.sqrt(C1p * C2p) * Math.sin((dhp * Math.PI / 180) / 2);
+
+  const Lp_avg = (L1 + L2) / 2;
+  const Cp_avg = (C1p + C2p) / 2;
+
+  let hp_avg;
+  if (C1p * C2p === 0) {
+    hp_avg = h1p + h2p;
+  } else if (Math.abs(h1p - h2p) <= 180) {
+    hp_avg = (h1p + h2p) / 2;
+  } else if (h1p + h2p < 360) {
+    hp_avg = (h1p + h2p + 360) / 2;
+  } else {
+    hp_avg = (h1p + h2p - 360) / 2;
+  }
+
+  const T = 1
+    - 0.17 * Math.cos((hp_avg - 30) * Math.PI / 180)
+    + 0.24 * Math.cos(2 * hp_avg * Math.PI / 180)
+    + 0.32 * Math.cos((3 * hp_avg + 6) * Math.PI / 180)
+    - 0.20 * Math.cos((4 * hp_avg - 63) * Math.PI / 180);
+
+  const SL = 1 + (0.015 * Math.pow(Lp_avg - 50, 2)) / Math.sqrt(20 + Math.pow(Lp_avg - 50, 2));
+  const SC = 1 + 0.045 * Cp_avg;
+  const SH = 1 + 0.015 * Cp_avg * T;
+
+  const Cp_avg7 = Math.pow(Cp_avg, 7);
+  const RT_term = -2 * Math.sqrt(Cp_avg7 / (Cp_avg7 + Math.pow(25, 7)))
+    * Math.sin(60 * Math.exp(-Math.pow((hp_avg - 275) / 25, 2)) * Math.PI / 180);
+
+  const dE = Math.sqrt(
+    Math.pow(dLp / (kL * SL), 2) +
+    Math.pow(dCp / (kC * SC), 2) +
+    Math.pow(dHp / (kH * SH), 2) +
+    RT_term * (dCp / (kC * SC)) * (dHp / (kH * SH))
+  );
+
+  return dE;
+}
diff --git a/src/js/gamut_viewer.js b/src/js/gamut_viewer.js
new file mode 100644
index 0000000..dd23b78
--- /dev/null
+++ b/src/js/gamut_viewer.js
@@ -0,0 +1,117 @@
+const { invoke } = window.__TAURI__.core;
+const { listen } = window.__TAURI__.event;
+
+let scene, camera, renderer, controls;
+let currentProfileMesh, sRgbMesh;
+
+export async function initGamutViewer() {
+    try {
+        const container = document.getElementById('gamutViewerContainer');
+        if (!container || typeof THREE === 'undefined') return;
+
+        scene = new THREE.Scene();
+        scene.background = new THREE.Color(0x111116);
+
+        camera = new THREE.PerspectiveCamera(45, container.clientWidth / container.clientHeight, 1, 1000);
+        camera.position.set(150, 100, 150);
+
+        renderer = new THREE.WebGLRenderer({ antialias: true });
+        renderer.setSize(container.clientWidth, container.clientHeight);
+        container.appendChild(renderer.domElement);
+
+        if (typeof THREE.OrbitControls !== 'undefined') {
+            controls = new THREE.OrbitControls(camera, renderer.domElement);
+            controls.enableDamping = true;
+        }
+
+        // Add CIELAB orientation helpers (Axes: X=a*, Y=L*, Z=b*)
+        const axesHelper = new THREE.AxesHelper(80);
+        scene.add(axesHelper);
+
+        // Lights
+        const ambientLight = new THREE.AmbientLight(0xffffff, 0.6);
+        scene.add(ambientLight);
+        const dirLight = new THREE.DirectionalLight(0xffffff, 0.8);
+        dirLight.position.set(100, 200, 100);
+        scene.add(dirLight);
+
+        animate();
+    } catch (err) {
+        console.warn("Gamut viewer initialization notice:", err);
+    }
+}
+
+function animate() {
+    requestAnimationFrame(animate);
+    if (controls) controls.update();
+    if (renderer && scene && camera) renderer.render(scene, camera);
+}
+
+function parseCGATS(text) {
+    const lines = text.split('\n');
+    let dataStarted = false;
+    const points = [];
+
+    for (const line of lines) {
+        if (line.startsWith('BEGIN_DATA')) {
+            dataStarted = true;
+            continue;
+        }
+        if (line.startsWith('END_DATA')) break;
+
+        if (dataStarted) {
+            const parts = line.trim().split(/\s+/);
+            if (parts.length >= 4) {
+                const L = parseFloat(parts[1]);
+                const a = parseFloat(parts[2]);
+                const b = parseFloat(parts[3]);
+                if (!isNaN(L) && !isNaN(a) && !isNaN(b)) {
+                    points.push({ L, a, b });
+                }
+            }
+        }
+    }
+    return points;
+}
+
+export async function loadGamutMesh(gamFilePath, color = 0x3b82f6, isWireframe = false) {
+    try {
+        const base64Data = await invoke('read_file_base64', { path: gamFilePath });
+        const text = atob(base64Data);
+        const points = parseCGATS(text);
+        if (points.length < 3) return null;
+
+        const coords = [];
+        const vertices = new Float32Array(points.length * 3);
+
+        points.forEach((pt, i) => {
+            coords.push(pt.a, pt.b);
+            vertices[i * 3] = pt.a;     // X = a*
+            vertices[i * 3 + 1] = pt.L; // Y = L*
+            vertices[i * 3 + 2] = pt.b; // Z = b*
+        });
+
+        if (typeof Delaunator === 'undefined') return null;
+        const delaunay = new Delaunator(coords);
+
+        const geometry = new THREE.BufferGeometry();
+        geometry.setAttribute('position', new THREE.BufferAttribute(vertices, 3));
+        geometry.setIndex(Array.from(delaunay.triangles));
+        geometry.computeVertexNormals();
+
+        const material = new THREE.MeshLambertMaterial({
+            color: color,
+            wireframe: isWireframe,
+            transparent: true,
+            opacity: isWireframe ? 0.4 : 0.75,
+            side: THREE.DoubleSide
+        });
+
+        const mesh = new THREE.Mesh(geometry, material);
+        scene.add(mesh);
+        return mesh;
+    } catch (e) {
+        console.error("Failed to load gamut mesh:", e);
+        return null;
+    }
+}
diff --git a/src/js/printtarg.js b/src/js/printtarg.js
new file mode 100644
index 0000000..b940dc8
--- /dev/null
+++ b/src/js/printtarg.js
@@ -0,0 +1,226 @@
+const { invoke } = window.__TAURI__.core;
+const { listen } = window.__TAURI__.event;
+import { setStage2Result } from './chartread.js';
+
+// Module-level state: set by Stage 1 when it completes
+let stage1Basename = "";
+let stage1Cwd = "";
+
+/**
+ * Called by targen.js (or app.js) after Stage 1 completes.
+ * Passes the basename and working directory forward.
+ */
+export function setStage1Result(basename, cwd) {
+  stage1Basename = basename;
+  stage1Cwd = cwd;
+}
+
+export function initPrinttarg() {
+  const instrumentSelect = document.getElementById("instrumentSelect");
+  const pageSizeSelect = document.getElementById("pageSizeSelect");
+  const customPageSizeRow = document.getElementById("customPageSizeRow");
+  const customPageW = document.getElementById("customPageW");
+  const customPageH = document.getElementById("customPageH");
+  const bitDepthRadios = document.querySelectorAll('input[name="bitDepth"]');
+  const tiffDpi = document.getElementById("tiffDpi");
+  const btnCreateLayout = document.getElementById("btnCreateLayout");
+  const logContainer = document.getElementById("printtargLogContainer");
+  const logPre = document.getElementById("printtargLog");
+  const tiffGallery = document.getElementById("tiffGallery");
+  const galleryInfo = document.getElementById("galleryInfo");
+  const galleryGrid = document.getElementById("galleryGrid");
+
+  // Show/hide custom page size inputs
+  pageSizeSelect.addEventListener("change", (e) => {
+    if (e.target.value === "custom") {
+      customPageSizeRow.classList.remove("hidden");
+    } else {
+      customPageSizeRow.classList.add("hidden");
+    }
+  });
+
+  // Create Layout button
+  btnCreateLayout.addEventListener("click", async () => {
+    // Validate that Stage 1 has been completed
+    if (!stage1Basename) {
+      logPre.textContent = "[ERROR] No .ti1 file available. Complete Stage 1 first.\n";
+      logContainer.classList.remove("hidden");
+      return;
+    }
+
+    logPre.textContent = "";
+    logContainer.classList.remove("hidden");
+    tiffGallery.classList.add("hidden");
+    galleryGrid.innerHTML = "";
+    btnCreateLayout.disabled = true;
+
+    // Determine page size
+    let pageSize = pageSizeSelect.value;
+    if (pageSize === "custom") {
+      const w = parseInt(customPageW.value, 10);
+      const h = parseInt(customPageH.value, 10);
+      if (!w || !h || w < 50 || h < 50) {
+        logPre.textContent = "[ERROR] Custom page size must have width and height ≥ 50mm.\n";
+        btnCreateLayout.disabled = false;
+        return;
+      }
+      pageSize = `${w}x${h}`;
+    }
+
+    // Determine bit depth
+    let bitDepth = 8;
+    bitDepthRadios.forEach(radio => {
+      if (radio.checked) bitDepth = parseInt(radio.value, 10);
+    });
+
+    const config = {
+      instrument: instrumentSelect.value,
+      page_size: pageSize,
+      bit_depth: bitDepth,
+      dpi: parseInt(tiffDpi.value, 10),
+      basename: stage1Basename,
+      cwd: stage1Cwd,
+    };
+
+    const processId = `printtarg_${stage1Basename}`;
+
+    // Accumulate all stdout lines to extract JSON manifest at the end
+    let stdoutAccumulator = "";
+
+    try {
+      const unlistenStdout = await listen("process:stdout", (event) => {
+        if (event.payload.id === processId && event.payload.line) {
+          stdoutAccumulator += event.payload.line + "\n";
+          logPre.textContent += event.payload.line + "\n";
+          logPre.scrollTop = logPre.scrollHeight;
+        }
+      });
+
+      const unlistenStderr = await listen("process:stderr", (event) => {
+        if (event.payload.id === processId && event.payload.line) {
+          logPre.textContent += "ERR: " + event.payload.line + "\n";
+          logPre.scrollTop = logPre.scrollHeight;
+        }
+      });
+
+      const unlistenExit = await listen("process:exit", (event) => {
+        if (event.payload.id === processId) {
+          unlistenStdout();
+          unlistenStderr();
+          unlistenExit();
+
+          if (event.payload.code === 0) {
+            logPre.textContent += "\n[SUCCESS] printtarg completed successfully.\n";
+            btnCreateLayout.disabled = false;
+
+            // Parse the JSON manifest from stdout
+            const manifest = extractManifest(stdoutAccumulator);
+            if (manifest && manifest.pages && manifest.pages.length > 0) {
+              renderTiffGallery(manifest, config.cwd);
+            }
+
+            setStage2Result(stage1Basename, stage1Cwd);
+            advanceToStage3();
+          } else {
+            logPre.textContent += `\n[ERROR] printtarg exited with code ${event.payload.code}.\n`;
+            btnCreateLayout.disabled = false;
+          }
+        }
+      });
+
+      logPre.textContent = "Starting printtarg...\n";
+      await invoke("run_printtarg", { config });
+
+    } catch (err) {
+      logPre.textContent += `\n[INVOKE ERROR] ${err}\n`;
+      btnCreateLayout.disabled = false;
+    }
+  });
+
+  /**
+   * Extract the JSON manifest object from the accumulated stdout.
+   * The manifest is emitted by printtarg -u as a JSON block starting with { and ending with }.
+   * It always appears at the end of stdout, after all "Creating file..." lines.
+   */
+  function extractManifest(stdout) {
+    try {
+      // Find the last JSON object in the output
+      const jsonStart = stdout.lastIndexOf('{\n  "event": "manifest"');
+      if (jsonStart === -1) return null;
+      const jsonEnd = stdout.indexOf('\n}', jsonStart);
+      if (jsonEnd === -1) return null;
+      const jsonStr = stdout.substring(jsonStart, jsonEnd + 2);
+      return JSON.parse(jsonStr);
+    } catch (e) {
+      console.error("Failed to parse printtarg manifest:", e);
+      return null;
+    }
+  }
+
+  /**
+   * Render TIFF preview gallery using base64-encoded images from the backend.
+   * @param {Object} manifest - The parsed JSON manifest from printtarg -u
+   * @param {string} cwd - The working directory where TIFFs were generated
+   */
+  async function renderTiffGallery(manifest, cwd) {
+    tiffGallery.classList.remove("hidden");
+
+    const pageCount = manifest.pages.length;
+    const totalPatches = manifest.pages.reduce((sum, p) => sum + p.patches, 0);
+    const dims = manifest.pages[0];
+    galleryInfo.textContent = `${pageCount} page(s) · ${totalPatches} patches · ${dims.width_mm} × ${dims.height_mm} mm per page`;
+
+    for (const page of manifest.pages) {
+      const sep = cwd.includes('\\') ? '\\' : '/';
+      const filePath = cwd ? `${cwd}${sep}${page.filename}` : page.filename;
+
+      const card = document.createElement("div");
+      card.className = "gallery-card";
+
+      const label = document.createElement("div");
+      label.className = "gallery-label";
+      label.textContent = `${page.filename} (${page.patches} patches)`;
+      card.appendChild(label);
+
+      try {
+        const base64Data = await invoke("read_file_base64", { path: filePath });
+        const img = document.createElement("img");
+        img.src = `data:image/tiff;base64,${base64Data}`;
+        img.alt = page.filename;
+        // TIFF may not render natively in all browsers — provide a fallback
+        img.onerror = () => {
+          img.remove();
+          const fallback = document.createElement("div");
+          fallback.className = "gallery-fallback";
+          fallback.innerHTML = `<span class="file-icon">📄</span><span>${page.filename}</span><span class="file-size">${page.patches} patches</span>`;
+          card.insertBefore(fallback, label.nextSibling);
+        };
+        card.appendChild(img);
+      } catch (err) {
+        const fallback = document.createElement("div");
+        fallback.className = "gallery-fallback";
+        fallback.innerHTML = `<span class="file-icon">📄</span><span>${page.filename}</span><span class="file-size">Preview unavailable</span>`;
+        card.appendChild(fallback);
+      }
+
+      galleryGrid.appendChild(card);
+    }
+  }
+}
+
+function advanceToStage3() {
+  const steps = document.querySelectorAll('.step');
+  const stages = document.querySelectorAll('.stage');
+
+  steps.forEach(s => s.classList.remove('active'));
+  if (steps[2]) steps[2].classList.add('active');
+
+  stages.forEach(s => {
+    s.classList.remove('active');
+    s.classList.add('hidden');
+  });
+  if (stages[2]) {
+    stages[2].classList.remove('hidden');
+    stages[2].classList.add('active');
+  }
+}
diff --git a/src/js/profcheck.js b/src/js/profcheck.js
new file mode 100644
index 0000000..49677c6
--- /dev/null
+++ b/src/js/profcheck.js
@@ -0,0 +1,137 @@
+const { invoke } = window.__TAURI__.core;
+const { listen } = window.__TAURI__.event;
+
+let profileBasename = "";
+let profileCwd = "";
+
+/**
+ * Called by colprof.js after Stage 4 completes.
+ */
+export function setStage4Result(basename, cwd) {
+  profileBasename = basename;
+  profileCwd = cwd;
+}
+
+export function initProfcheck() {
+  const btnVerify = document.getElementById("btnVerify");
+  const logContainer = document.getElementById("profcheckLogContainer");
+  const logPre = document.getElementById("profcheckLog");
+  const reportCard = document.getElementById("profcheckReportCard");
+  const avgDeEl = document.getElementById("profcheckAvgDe");
+  const maxDeEl = document.getElementById("profcheckMaxDe");
+  const rmsDeEl = document.getElementById("profcheckRmsDe");
+  const badgeEl = document.getElementById("profcheckBadge");
+
+  if (!btnVerify) return;
+
+  btnVerify.addEventListener("click", async () => {
+    const basename = profileBasename || "test_target";
+    const cwd = profileCwd || "";
+
+    const sep = cwd.includes('\\') ? '\\' : '/';
+    const ti3Path = cwd ? `${cwd}${sep}${basename}.ti3` : `${basename}.ti3`;
+    const iccPath = cwd ? `${cwd}${sep}${basename}.icc` : `${basename}.icc`;
+
+    logPre.textContent = "";
+    logContainer.classList.remove("hidden");
+    reportCard.classList.add("hidden");
+    btnVerify.disabled = true;
+
+    const config = {
+      ti3_path: ti3Path,
+      icc_path: iccPath,
+      cwd: cwd,
+    };
+
+    const processId = `profcheck_${ti3Path}`;
+    let stdoutAccumulator = "";
+
+    try {
+      const unlistenStdout = await listen("process:stdout", (event) => {
+        if (event.payload.id === processId && event.payload.line) {
+          stdoutAccumulator += event.payload.line + "\n";
+          logPre.textContent += event.payload.line + "\n";
+          logPre.scrollTop = logPre.scrollHeight;
+        }
+      });
+
+      const unlistenStderr = await listen("process:stderr", (event) => {
+        if (event.payload.id === processId && event.payload.line) {
+          logPre.textContent += "ERR: " + event.payload.line + "\n";
+          logPre.scrollTop = logPre.scrollHeight;
+        }
+      });
+
+      const unlistenExit = await listen("process:exit", (event) => {
+        if (event.payload.id === processId) {
+          unlistenStdout();
+          unlistenStderr();
+          unlistenExit();
+          btnVerify.disabled = false;
+
+          if (event.payload.code === 0) {
+            logPre.textContent += "\n[SUCCESS] profcheck verification finished.\n";
+            parseAndRenderReport(stdoutAccumulator);
+          } else {
+            logPre.textContent += `\n[ERROR] profcheck exited with code ${event.payload.code}.\n`;
+          }
+        }
+      });
+
+      await invoke("run_profcheck", { config });
+    } catch (err) {
+      logPre.textContent += `\n[INVOKE ERROR] ${err}\n`;
+      btnVerify.disabled = false;
+    }
+  });
+
+  function parseAndRenderReport(stdout) {
+    reportCard.classList.remove("hidden");
+
+    let avgDe = 0.0;
+    let maxDe = 0.0;
+    let rmsDe = 0.0;
+
+    // Check if JSON output is present
+    const jsonMatch = stdout.match(/\{[\s\S]*"avg_de"[\s\S]*\}/);
+    if (jsonMatch) {
+      try {
+        const json = JSON.parse(jsonMatch[0]);
+        avgDe = json.avg_de || 0;
+        maxDe = json.max_de || json.peak_de || 0;
+        rmsDe = json.rms_de || 0;
+      } catch (e) {
+        console.error("JSON parse error:", e);
+      }
+    } else {
+      // Regex fallbacks for standard profcheck output
+      const avgMatch = stdout.match(/avg\.\s*dE\s*=\s*([\d\.]+)/i) || stdout.match(/average\s*dE\s*:\s*([\d\.]+)/i);
+      const maxMatch = stdout.match(/max\.\s*dE\s*=\s*([\d\.]+)/i) || stdout.match(/peak\s*dE\s*:\s*([\d\.]+)/i);
+      const rmsMatch = stdout.match(/rms\.\s*dE\s*=\s*([\d\.]+)/i) || stdout.match(/rms\s*dE\s*:\s*([\d\.]+)/i);
+
+      if (avgMatch) avgDe = parseFloat(avgMatch[1]);
+      if (maxMatch) maxDe = parseFloat(maxMatch[1]);
+      if (rmsMatch) rmsDe = parseFloat(rmsMatch[1]);
+    }
+
+    avgDeEl.textContent = avgDe.toFixed(2);
+    maxDeEl.textContent = maxDe.toFixed(2);
+    rmsDeEl.textContent = rmsDe.toFixed(2);
+
+    // Quality verdict
+    badgeEl.className = "report-badge";
+    if (avgDe < 1.0) {
+      badgeEl.textContent = "EXCELLENT";
+      badgeEl.classList.add("badge-excellent");
+    } else if (avgDe < 2.0) {
+      badgeEl.textContent = "GOOD";
+      badgeEl.classList.add("badge-good");
+    } else if (avgDe < 4.0) {
+      badgeEl.textContent = "ACCEPTABLE";
+      badgeEl.classList.add("badge-acceptable");
+    } else {
+      badgeEl.textContent = "POOR";
+      badgeEl.classList.add("badge-poor");
+    }
+  }
+}
diff --git a/src/js/settings.js b/src/js/settings.js
new file mode 100644
index 0000000..2d98595
--- /dev/null
+++ b/src/js/settings.js
@@ -0,0 +1,40 @@
+const { invoke } = window.__TAURI__.core;
+
+export async function initSettings() {
+    const dialog = document.getElementById('settingsDialog');
+    const openBtn = document.getElementById('openSettingsBtn');
+    const saveBtn = document.getElementById('saveSettingsBtn');
+    const closeBtn = document.getElementById('closeSettingsBtn');
+
+    if (!dialog || !openBtn) return;
+
+    openBtn.addEventListener('click', async () => {
+        try {
+            const settings = await invoke('load_settings');
+            document.getElementById('argyll_binary_dir').value = settings.argyll_binary_dir || '';
+            document.getElementById('default_instrument').value = settings.default_instrument || '';
+            dialog.showModal();
+        } catch (e) {
+            console.error("Failed to load settings:", e);
+        }
+    });
+
+    if (closeBtn) {
+        closeBtn.addEventListener('click', () => dialog.close());
+    }
+
+    if (saveBtn) {
+        saveBtn.addEventListener('click', async () => {
+            const settings = {
+                argyll_binary_dir: document.getElementById('argyll_binary_dir').value.trim() || null,
+                default_instrument: document.getElementById('default_instrument').value.trim() || null
+            };
+            try {
+                await invoke('save_settings', { settings });
+                dialog.close();
+            } catch (e) {
+                console.error("Failed to save settings:", e);
+            }
+        });
+    }
+}
diff --git a/src/js/swatch_grid.js b/src/js/swatch_grid.js
new file mode 100644
index 0000000..8856dfc
--- /dev/null
+++ b/src/js/swatch_grid.js
@@ -0,0 +1,127 @@
+import { computeDeltaE00 } from './delta_e.js';
+import { labToCss, deviceRgbToCss } from './color_convert.js';
+
+const { listen } = window.__TAURI__.event;
+
+let unlistenJsonRow = null;
+
+/**
+ * Start listening for row events from a chartread process.
+ * @param {string} processId - The process ID (e.g. "chartread_my_profile")
+ */
+export async function startSwatchListener(processId) {
+  const grid = document.getElementById("swatchGrid");
+  const progressBar = document.getElementById("readProgress");
+  const progressText = document.getElementById("readProgressText");
+  const statsPanel = document.getElementById("readStats");
+
+  // Clear previous state
+  grid.innerHTML = "";
+  let totalPatches = 0;
+  let totalDeltaE = 0;
+  let patchCount = 0;
+  let maxDeltaE = 0;
+
+  unlistenJsonRow = await listen("process:json_row", (event) => {
+    if (event.payload.id !== processId) return;
+
+    let data;
+    try {
+      data = JSON.parse(event.payload.json);
+    } catch (e) {
+      console.error("Failed to parse json_row:", e);
+      return;
+    }
+
+    if (data.event !== "row_complete") return;
+
+    // Update progress bar
+    const progress = ((data.row_index + 1) / data.total_rows) * 100;
+    if (progressBar) progressBar.style.width = `${progress}%`;
+    if (progressText) progressText.textContent = `Strip ${data.row_id} — ${data.row_index + 1} / ${data.total_rows}`;
+
+    // Create row container
+    const rowEl = document.createElement("div");
+    rowEl.className = "swatch-row";
+
+    const rowLabel = document.createElement("div");
+    rowLabel.className = "swatch-row-label";
+    rowLabel.textContent = data.row_id;
+    rowEl.appendChild(rowLabel);
+
+    const rowPatches = document.createElement("div");
+    rowPatches.className = "swatch-row-patches";
+
+    for (const patch of data.patches) {
+      if (patch.is_pad) continue; // Skip spacer patches
+
+      const patchEl = document.createElement("div");
+      patchEl.className = "swatch-patch";
+
+      // Determine the display colour
+      let bgColor;
+      if (patch.measured && patch.measured.Lab) {
+        bgColor = labToCss(patch.measured.Lab);
+      } else if (patch.device && patch.device.length === 3) {
+        bgColor = deviceRgbToCss(patch.device);
+      } else {
+        bgColor = "#888";
+      }
+
+      const swatch = document.createElement("div");
+      swatch.className = "swatch-color";
+      swatch.style.backgroundColor = bgColor;
+      patchEl.appendChild(swatch);
+
+      // Compute and display ΔE₀₀ if both expected and measured Lab are present
+      if (patch.expected && patch.expected.Lab && patch.measured && patch.measured.Lab) {
+        const deltaE = computeDeltaE00(patch.expected.Lab, patch.measured.Lab);
+
+        const deLabel = document.createElement("div");
+        deLabel.className = "swatch-de";
+        deLabel.textContent = deltaE.toFixed(1);
+
+        // Traffic light classification
+        if (deltaE < 2) {
+          patchEl.classList.add("de-good");       // Green
+        } else if (deltaE < 5) {
+          patchEl.classList.add("de-warning");     // Amber
+        } else {
+          patchEl.classList.add("de-bad");          // Red
+        }
+
+        patchEl.appendChild(deLabel);
+
+        // Accumulate stats
+        totalDeltaE += deltaE;
+        patchCount++;
+        if (deltaE > maxDeltaE) maxDeltaE = deltaE;
+      }
+
+      patchEl.title = `${patch.loc} (ID: ${patch.id})`;
+      rowPatches.appendChild(patchEl);
+    }
+
+    rowEl.appendChild(rowPatches);
+    grid.appendChild(rowEl);
+
+    // Scroll to bottom
+    grid.scrollTop = grid.scrollHeight;
+
+    // Update stats
+    if (statsPanel && patchCount > 0) {
+      const avgDe = (totalDeltaE / patchCount).toFixed(2);
+      statsPanel.textContent = `Avg ΔE₀₀: ${avgDe} · Max ΔE₀₀: ${maxDeltaE.toFixed(2)} · Patches: ${patchCount}`;
+    }
+  });
+}
+
+/**
+ * Stop listening for row events.
+ */
+export function stopSwatchListener() {
+  if (unlistenJsonRow) {
+    unlistenJsonRow();
+    unlistenJsonRow = null;
+  }
+}
diff --git a/src/js/targen.js b/src/js/targen.js
index 0b854e1..a6917cb 100644
--- a/src/js/targen.js
+++ b/src/js/targen.js
@@ -1,6 +1,7 @@
 const { invoke } = window.__TAURI__.core;
 const { listen } = window.__TAURI__.event;
 const { save } = window.__TAURI__.dialog;
+import { setStage1Result } from './printtarg.js';
 
 export function initTargen() {
   const colourSpaceRadios = document.querySelectorAll('input[name="colourSpace"]');
@@ -131,6 +132,7 @@ export function initTargen() {
             // In a real app we'd dispatch an event to advance the stepper here.
             // For now, we'll manually unlock stage 2 in the state.
             btnGenerate.disabled = false;
+            setStage1Result(basename, currentWorkingDir);
             advanceToStage2();
           } else {
             logPre.textContent += `\n[ERROR] Targen exited with code ${event.payload.code}.\n`;
diff --git a/src/styles/main.css b/src/styles/main.css
index b4b182b..0e47ae3 100644
--- a/src/styles/main.css
+++ b/src/styles/main.css
@@ -225,7 +225,8 @@ button:disabled {
   font-size: 0.9em;
 }
 
-#targenLog {
+#targenLog,
+#printtargLog {
   margin: 0;
   font-family: monospace;
   font-size: 0.9em;
@@ -234,3 +235,472 @@ button:disabled {
   overflow-y: auto;
   white-space: pre-wrap;
 }
+
+/* ========================================
+   Stage 2: Warning Banner
+   ======================================== */
+.warning-banner {
+  display: flex;
+  align-items: flex-start;
+  gap: 12px;
+  background: rgba(255, 152, 0, 0.12);
+  border: 1px solid rgba(255, 152, 0, 0.4);
+  border-left: 4px solid #ff9800;
+  border-radius: 6px;
+  padding: 16px;
+  margin-bottom: 20px;
+}
+
+.warning-icon {
+  font-size: 1.5rem;
+  flex-shrink: 0;
+  line-height: 1;
+}
+
+.warning-text strong {
+  display: block;
+  color: #ffb74d;
+  margin-bottom: 6px;
+}
+
+.warning-text p {
+  margin: 0;
+  font-size: 0.9em;
+  color: #ccc;
+  line-height: 1.5;
+}
+
+/* ========================================
+   Stage 2: TIFF Gallery
+   ======================================== */
+.tiff-gallery {
+  margin-top: 24px;
+}
+
+.tiff-gallery h3 {
+  margin: 0 0 8px 0;
+  color: #fff;
+}
+
+.gallery-info {
+  font-size: 0.9em;
+  color: #888;
+  margin-bottom: 16px;
+}
+
+.gallery-grid {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
+  gap: 16px;
+}
+
+.gallery-card {
+  background: var(--panel-color);
+  border: 1px solid var(--border-color);
+  border-radius: 8px;
+  overflow: hidden;
+  transition: border-color 0.2s;
+}
+
+.gallery-card:hover {
+  border-color: var(--accent-color);
+}
+
+.gallery-card img {
+  width: 100%;
+  height: auto;
+  display: block;
+  background: #fff;
+}
+
+.gallery-label {
+  padding: 10px 12px;
+  font-size: 0.85em;
+  color: #aaa;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.gallery-fallback {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  padding: 30px 16px;
+  background: var(--bg-color);
+  gap: 8px;
+}
+
+.gallery-fallback .file-icon {
+  font-size: 2.5rem;
+}
+
+.gallery-fallback .file-size {
+  font-size: 0.8em;
+  color: #666;
+}
+
+/* ========================================
+   Stage 3: chartread State Machine UI
+   ======================================== */
+.chartread-status {
+  background: var(--panel-color);
+  border: 1px solid var(--border-color);
+  border-radius: 8px;
+  padding: 16px;
+  margin-bottom: 16px;
+}
+
+.status-label {
+  font-size: 0.85em;
+  color: #888;
+  margin-bottom: 8px;
+}
+
+.status-label span {
+  color: var(--accent-color);
+  font-weight: bold;
+  text-transform: uppercase;
+}
+
+.status-prompt {
+  font-size: 1.1em;
+  color: #fff;
+  line-height: 1.4;
+  min-height: 2.8em;
+}
+
+.chartread-actions {
+  display: flex;
+  gap: 10px;
+  margin-bottom: 16px;
+  flex-wrap: wrap;
+}
+
+button.danger {
+  background-color: #c62828;
+  color: white;
+  border: none;
+  padding: 10px 20px;
+  font-size: 1rem;
+  border-radius: 4px;
+  cursor: pointer;
+}
+
+button.danger:hover {
+  background-color: #e53935;
+}
+
+/* Progress Bar */
+.read-progress-container {
+  width: 100%;
+  height: 8px;
+  background: var(--bg-color);
+  border-radius: 4px;
+  overflow: hidden;
+  margin-bottom: 6px;
+}
+
+.read-progress-bar {
+  height: 100%;
+  background: linear-gradient(90deg, var(--accent-color), #4fc3f7);
+  border-radius: 4px;
+  transition: width 0.3s ease;
+}
+
+.read-progress-text {
+  font-size: 0.85em;
+  color: #888;
+  margin-bottom: 12px;
+}
+
+.read-stats {
+  font-size: 0.9em;
+  color: #aaa;
+  margin-bottom: 16px;
+}
+
+/* ========================================
+   Stage 3: Swatch Grid
+   ======================================== */
+.swatch-grid {
+  max-height: 500px;
+  overflow-y: auto;
+  border: 1px solid var(--border-color);
+  border-radius: 8px;
+  background: var(--panel-color);
+  padding: 12px;
+  margin-bottom: 16px;
+}
+
+.swatch-row {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  margin-bottom: 8px;
+}
+
+.swatch-row-label {
+  min-width: 30px;
+  font-weight: bold;
+  font-size: 0.85em;
+  color: #888;
+  text-align: center;
+}
+
+.swatch-row-patches {
+  display: flex;
+  gap: 4px;
+  flex-wrap: wrap;
+}
+
+.swatch-patch {
+  width: 36px;
+  text-align: center;
+  border: 2px solid transparent;
+  border-radius: 4px;
+  overflow: hidden;
+  transition: border-color 0.2s;
+}
+
+.swatch-color {
+  width: 100%;
+  height: 28px;
+}
+
+.swatch-de {
+  font-size: 0.65em;
+  padding: 2px 0;
+  color: #ccc;
+  background: rgba(0,0,0,0.3);
+}
+
+/* Traffic light ΔE indicators */
+.swatch-patch.de-good {
+  border-color: #4caf50;
+}
+
+.swatch-patch.de-warning {
+  border-color: #ff9800;
+}
+
+.swatch-patch.de-bad {
+  border-color: #f44336;
+}
+
+/* Process log for chartread */
+#chartreadLog {
+  margin: 0;
+  font-family: monospace;
+  font-size: 0.9em;
+  color: #ccc;
+  max-height: 200px;
+  overflow-y: auto;
+  white-space: pre-wrap;
+}
+
+/* ========================================
+   Stage 4: Spinner & Success Card
+   ======================================== */
+.spinner-container {
+  display: flex;
+  align-items: center;
+  gap: 16px;
+  background: var(--panel-color);
+  border: 1px solid var(--border-color);
+  border-radius: 8px;
+  padding: 16px;
+  margin-top: 16px;
+  margin-bottom: 16px;
+}
+
+.spinner {
+  width: 24px;
+  height: 24px;
+  border: 3px solid rgba(255, 255, 255, 0.2);
+  border-top-color: var(--accent-color);
+  border-radius: 50%;
+  animation: spin 1s linear infinite;
+}
+
+@keyframes spin {
+  to { transform: rotate(360deg); }
+}
+
+.stage-label {
+  font-size: 1rem;
+  color: #ddd;
+}
+
+.success-card {
+  background: rgba(76, 175, 80, 0.1);
+  border: 1px solid #4caf50;
+  border-radius: 8px;
+  padding: 20px;
+  margin-top: 16px;
+  margin-bottom: 16px;
+}
+
+.success-card h3 {
+  color: #4caf50;
+  margin-top: 0;
+  margin-bottom: 8px;
+}
+
+.success-card p {
+  color: #ccc;
+  margin-bottom: 16px;
+}
+
+/* ========================================
+   Stage 5: Report Card
+   ======================================== */
+.report-card {
+  background: var(--panel-color);
+  border: 1px solid var(--border-color);
+  border-radius: 8px;
+  padding: 20px;
+  margin-top: 16px;
+  margin-bottom: 16px;
+}
+
+.report-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 20px;
+}
+
+.report-header h3 {
+  margin: 0;
+  font-size: 1.2rem;
+}
+
+.report-badge {
+  padding: 4px 12px;
+  border-radius: 12px;
+  font-weight: bold;
+  font-size: 0.85rem;
+  letter-spacing: 0.5px;
+}
+
+.badge-excellent {
+  background: rgba(76, 175, 80, 0.2);
+  color: #4caf50;
+  border: 1px solid #4caf50;
+}
+
+.badge-good {
+  background: rgba(33, 150, 243, 0.2);
+  color: #2196f3;
+  border: 1px solid #2196f3;
+}
+
+.badge-acceptable {
+  background: rgba(255, 152, 0, 0.2);
+  color: #ff9800;
+  border: 1px solid #ff9800;
+}
+
+.badge-poor {
+  background: rgba(244, 67, 54, 0.2);
+  color: #f44336;
+  border: 1px solid #f44336;
+}
+
+.report-metrics {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
+  gap: 16px;
+  margin-bottom: 16px;
+}
+
+.metric-box {
+  background: var(--bg-color);
+  border: 1px solid var(--border-color);
+  border-radius: 6px;
+  padding: 16px;
+  text-align: center;
+}
+
+.metric-value {
+  display: block;
+  font-size: 1.8rem;
+  font-weight: bold;
+  color: #fff;
+}
+
+.metric-label {
+  font-size: 0.8rem;
+  color: #888;
+}
+
+.report-footnote {
+  font-size: 0.85rem;
+  color: #888;
+  border-top: 1px dashed var(--border-color);
+  padding-top: 12px;
+}
+
+/* ========================================
+   Stage 5: Gamut Viewer & Settings Modal
+   ======================================== */
+.gamut-viewer-section {
+  margin-top: 24px;
+}
+
+#gamutViewerContainer {
+  width: 100%;
+  height: 400px;
+  background: #111116;
+  border: 1px solid var(--border-color);
+  border-radius: 8px;
+  overflow: hidden;
+}
+
+.brand {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+}
+
+.icon-btn {
+  background: none;
+  border: none;
+  font-size: 1.2rem;
+  cursor: pointer;
+  padding: 4px;
+  border-radius: 4px;
+}
+
+.icon-btn:hover {
+  background: var(--border-color);
+}
+
+.settings-modal {
+  background: var(--panel-color);
+  color: #fff;
+  border: 1px solid var(--border-color);
+  border-radius: 12px;
+  padding: 24px;
+  max-width: 480px;
+  width: 90%;
+}
+
+.settings-modal::backdrop {
+  background: rgba(0, 0, 0, 0.6);
+}
+
+.modal-content h2 {
+  margin-top: 0;
+  margin-bottom: 20px;
+}
+
+.modal-actions {
+  display: flex;
+  gap: 12px;
+  margin-top: 24px;
+  justify-content: flex-end;
+}
+