Give ACRIPES a straight BT.709 ramp and end-only tone

src/utils/colorUtils.ts

@@ -172,17 +172,22 @@ export function getSkiaColorMatrix(baseFilter: BaseFilter, adj: ColorAdjustments
       0, 0, 0, 1, 0,
     ];
   } else if (baseFilter === 'monochrome') {
-    // Acros: pure BT.709 grayscale, zero colour leakage. Contrast is a touch
-    // above neutral and eased around mid-grey, so the darks keep texture
-    // instead of plugging to black. (Grain/sharpness stay the user's call —
-    // a film sim here is the colour grade only.)
-    const r = 0.2339;
-    const g = 0.7867;
-    const b = 0.0794;
+    // Acros: pure BT.709 grayscale, zero colour leakage, and NO gain or offset.
+    // The weights sum to 1.0 and the offset is 0, so this matrix is a straight
+    // luminance readout: nothing clips at either end and every grey step the
+    // sensor recorded survives. (An earlier 1.10x / -0.05 version plugged every
+    // black below ~5% and blew every white above ~95% — exactly the fine
+    // graduation this stock is prized for.) The deep black and the highlight
+    // shoulder live in FILM_TONE (toneShader.ts), where the curve can be shaped
+    // one end at a time without touching the midtones. (Grain/sharpness stay
+    // the user's call — a film sim here is the colour grade only.)
+    const r = 0.2126;
+    const g = 0.7152;
+    const b = 0.0722;
     matrix = [
-      r, g, b, 0, -0.05,
-      r, g, b, 0, -0.05,
-      r, g, b, 0, -0.05,
+      r, g, b, 0, 0,
+      r, g, b, 0, 0,
+      r, g, b, 0, 0,
       0, 0, 0, 1, 0,
     ];
   }