diff --git a/src/utils/colorUtils.ts b/src/utils/colorUtils.ts
index e8118da..4ad087c 100644
--- a/src/utils/colorUtils.ts
+++ b/src/utils/colorUtils.ts
@@ -150,6 +150,18 @@ function normalizeGainLuma(gain: number[]): { r: number; g: number; b: number }
   return { r: gain[0] * s, g: gain[1] * s, b: gain[2] * s };
 }
 
+// Brightness a stock carries BY ITSELF, in the EXPOSURE slider's own units.
+// It is part of the look, not a knob the user set, so it never reaches the
+// panel (a sim's adjustments stay neutral — see FILM_SIMS in defaultRecipes)
+// and the slider reads 0 while the render is already lifted. Keyed by stock
+// because that is what the renderers know: `baseFilter` travels with every
+// recipe, an armed sim id does not. ponytail: one entry, one stock; if two
+// sims ever need to share a matrix with different brightness, the key has to
+// move to the sim id.
+const STOCK_EXPOSURE: Partial<Record<BaseFilter, number>> = {
+  'leica-vivid': 2, // LC STREETLIFE VIVID reads bright straight off the shutter
+};
+
 // Generate a 4x5 ColorMatrix (array of 20 floats) based on base style and
 // adjustments. Tone-domain knobs (dynamicRange/highlight/shadow) and the
 // exposure-compensation EV gain are intentionally NOT part of the matrix —
@@ -157,7 +169,9 @@ function normalizeGainLuma(gain: number[]): { r: number; g: number; b: number }
 // and EV is applied either as hardware AE bias (camera) or by the caller via
 // applyExposureGain (library), never doubled.
 export function getSkiaColorMatrix(baseFilter: BaseFilter, adj: ColorAdjustments): number[] {
-  const exposure = adj.exposure;
+  // The stock's own brightness rides with the slider: same maths, same band
+  // (it is a property of the look, not of this photo's edit).
+  const exposure = adj.exposure + (STOCK_EXPOSURE[baseFilter] ?? 0);
   const contrast = adj.contrast;
   const saturation = adj.saturation;
   const temperature = adj.temperature;
@@ -270,9 +284,10 @@ export function getSkiaColorMatrix(baseFilter: BaseFilter, adj: ColorAdjustments
     // digital era: ~20% of chroma gain (still well under Velvia's 39%, so it
     // sparkles instead of shouting) on the same warm R>G>B bias CLASSIC has, so
     // VIVID is a brighter read of one look rather than a second, neutral one.
-    // No positive lift here: the brightness is the sim's own exposure value
-    // (defaultRecipes), which keeps the matrix inside 0..1 and pure white out of
-    // the clip — white lands at most at 1.000 on the red row.
+    // No positive lift here either, so the matrix stays inside 0..1 and pure
+    // white stays out of the clip — white lands at most at 1.000 on the red row.
+    // The brightness this look is known for is STOCK_EXPOSURE below: a fixed
+    // exposure move of the stock itself, never a chroma trick.
     matrix = [
       1.125, -0.100, -0.010, 0, -0.015,
       -0.055, 1.110, -0.055, 0, -0.005,
diff --git a/src/utils/defaultRecipes.ts b/src/utils/defaultRecipes.ts
index 636009b..3e0bd20 100644
--- a/src/utils/defaultRecipes.ts
+++ b/src/utils/defaultRecipes.ts
@@ -29,13 +29,37 @@ export const DEFAULT_ADJUSTMENTS: ColorAdjustments = {
   exposureCompensation: 0,
 };
 
-// Standard Fuji film simulations. These are the fixed "look" presets shown at
-// the front of the PRESETS chip row: tapping one applies the simulation — its
-// baseFilter colour matrix plus whatever the stock itself carries outside the
-// matrix (its FILM_TONE curve, and a grain amount when the grain IS the look,
-// as on Acros). Every other knob still resets to its neutral default (0 /
-// auto), so a sim is a clean starting point, never a baked recipe; any further
-// look (DR, CC, contrast, more grain) is added by the user afterwards.
+// Standard film simulations. These are the fixed "look" presets shown at the
+// front of the PRESETS chip row.
+//
+// RULE — a sim carries COLOUR AND TONE ONLY, never an effect. Its whole look
+// must come from its baseFilter colour matrix plus its FILM_TONE curve
+// (toneShader.ts): the two things that *define* the stock. No grain, no
+// clarity, no exposure/saturation/shadow/highlight move — those are edits the
+// user makes afterwards, never something a sim bakes in. That is why every sim
+// below shares the neutral DEFAULT_ADJUSTMENTS verbatim; if a look ever needs
+// more, put it in the matrix or the tone curve instead.
+//
+// The one exception is a stock that is simply BRIGHTER: that is a fixed
+// exposure move of the look itself, so it lives in STOCK_EXPOSURE
+// (colorUtils.ts), keyed by baseFilter, where the preview and both exporters
+// already pick it up. It never lands here and never reaches the panel, so the
+// EXPOSURE slider still reads 0 on such a sim — LC STREETLIFE VIVID (+2).
+//
+// Reference only — what each sim stands for, so the colour choices can be
+// checked against the real stock. The UI keeps the sim names below.
+//
+//   PROVIPES              → PROVIA
+//   VELVIPES              → VELVIA
+//   CLASSIC CHRIPES       → CLASSIC CHROME
+//   CLASSIC VIVIDIPES     → VELVIA + CLASSIC CHROME (Chrome's blue row over
+//                           Velvia's red and green rows — see colorUtils.ts)
+//   CLASSIC NEGIPES       → Classic Negative
+//   ASTIPES               → Astia
+//   ETERNIPES             → Eterna
+//   ACRIPES               → Acros
+//   LC STREETLIFE CLASSIC → Leica Authentic Classic
+//   LC STREETLIFE VIVID   → Leica Vivid
 export interface FilmSim {
   id: string; // Recipe-like id used only while the sim is the current selection
   name: string;
@@ -51,20 +75,16 @@ export const FILM_SIMS: FilmSim[] = [
   { id: 'sim-classic-neg', name: 'CLASSIC NEGIPES', baseFilter: 'classic-neg', adjustments: { ...DEFAULT_ADJUSTMENTS } },
   { id: 'sim-astia', name: 'ASTIPES', baseFilter: 'astia', adjustments: { ...DEFAULT_ADJUSTMENTS } },
   { id: 'sim-eterna', name: 'ETERNIPES', baseFilter: 'eterna', adjustments: { ...DEFAULT_ADJUSTMENTS } },
-  { id: 'sim-acros', name: 'ACRIPES', baseFilter: 'monochrome', adjustments: { ...DEFAULT_ADJUSTMENTS, grain: 3 } },
+  { id: 'sim-acros', name: 'ACRIPES', baseFilter: 'monochrome', adjustments: { ...DEFAULT_ADJUSTMENTS } },
   // The rangefinder digital look (M/Q/SL) is not a film stock, so it ships as its own
-  // pair instead of one look that has to compromise:
+  // pair instead of one look that has to compromise. Both read off the
+  // 'leica'/'leica-vivid' colour matrices alone (neither has a FILM_TONE
+  // entry):
   //   CLASSIC — the stock character: deep solid darks, natural shadows, rich but
-  //     quiet colour. Its micro-contrast is CLARITY (a local unsharp mask in both
-  //     renderers), never a global saturation boost, and a whisker of grain
-  //     keeps it feeling like film rather than digital sharpness.
-  //   VIVID — the same channel separation opened up for the digital era: lifted
-  //     exposure, lifted shadows, a little colour. It reads bright and flattering
-  //     straight off the shutter, no editing pass needed.
-  // Both share the 'leica'/'leica-vivid' matrices; the tonal half is the sim's
-  // own adjustments, which every apply path now carries into the panel.
-  { id: 'sim-leica', name: 'LC STREETLIFE CLASSIC', baseFilter: 'leica', adjustments: { ...DEFAULT_ADJUSTMENTS, clarity: 2, grain: 1 } },
-  { id: 'sim-leica-vivid', name: 'LC STREETLIFE VIVID', baseFilter: 'leica-vivid', adjustments: { ...DEFAULT_ADJUSTMENTS, exposure: 2, saturation: 2, clarity: 2, shadow: 1, highlight: -1 } },
+  //     quiet colour.
+  //   VIVID — the same channel separation opened up for the digital era.
+  { id: 'sim-leica', name: 'LC STREETLIFE CLASSIC', baseFilter: 'leica', adjustments: { ...DEFAULT_ADJUSTMENTS } },
+  { id: 'sim-leica-vivid', name: 'LC STREETLIFE VIVID', baseFilter: 'leica-vivid', adjustments: { ...DEFAULT_ADJUSTMENTS } },
 ];
 
 // Film sim → full Recipe (never persisted; sims are applied on the fly).