diff --git a/packages/core/src/runtime/entry.test.ts b/packages/core/src/runtime/entry.test.ts
new file mode 100644
index 0000000000..74cc2e98a0
--- /dev/null
+++ b/packages/core/src/runtime/entry.test.ts
@@ -0,0 +1,132 @@
+// fallow-ignore-file code-duplication
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { HF_COLOR_GRADING_ATTR, serializeHfColorGrading } from "../colorGrading";
+import type { RuntimeTimelineLike } from "./types";
+
+function pausedTimeline(duration: number): RuntimeTimelineLike {
+  let time = 0;
+  return {
+    play: () => {},
+    pause: () => {},
+    seek: (t?: number) => (t === undefined ? time : (time = t)),
+    totalTime: (t?: number) => (t === undefined ? time : (time = t)),
+    time: () => time,
+    duration: () => duration,
+    add: () => {},
+    paused: () => true,
+    timeScale: () => {},
+    set: () => {},
+    getChildren: () => [],
+  };
+}
+
+function timed<K extends keyof HTMLElementTagNameMap>(
+  parent: Element,
+  tag: K,
+  start: string,
+): HTMLElementTagNameMap[K] {
+  const el = document.createElement(tag);
+  el.className = "clip";
+  el.setAttribute("data-start", start);
+  el.setAttribute("data-duration", "2");
+  el.setAttribute("data-track-index", "1");
+  parent.appendChild(el);
+  return el;
+}
+
+function mountRoot(): HTMLElement {
+  const root = document.createElement("div");
+  root.setAttribute("data-composition-id", "main");
+  root.setAttribute("data-root", "true");
+  root.setAttribute("data-start", "0");
+  root.setAttribute("data-width", "1920");
+  root.setAttribute("data-height", "1080");
+  document.body.appendChild(root);
+  window.__timelines = { main: pausedTimeline(10) };
+  return root;
+}
+
+async function evaluateRuntime(): Promise<void> {
+  vi.resetModules();
+  await import("./entry");
+}
+
+const visibility = (...els: HTMLElement[]) => els.map((el) => getComputedStyle(el).visibility);
+
+describe("runtime entry", () => {
+  afterEach(() => {
+    window.__hfRuntimeTeardown?.();
+    document.head.innerHTML = "";
+    document.body.innerHTML = "";
+    window.__timelines = {};
+    delete window.__player;
+    delete window.__playerReady;
+    delete window.__renderReady;
+    delete window.__hfTimelinesBuilding;
+    const win = window as {
+      __hyperframeRuntimeBootstrapped?: boolean;
+      __hfFirstPassHidden?: boolean;
+    };
+    delete win.__hyperframeRuntimeBootstrapped;
+    delete win.__hfFirstPassHidden;
+    delete (document as { readyState?: unknown }).readyState;
+  });
+
+  it("paints no timed clip, from script evaluation until the first visibility pass decides it", async () => {
+    const root = mountRoot();
+    const current = timed(root, "div", "0");
+    const later = timed(root, "div", "5");
+    const poster = timed(root, "img", "0");
+    // A composition script may write visibility inline before the runtime runs.
+    later.style.visibility = "visible";
+    // Readiness, which runs the first pass, waits while GSAP batches timelines.
+    window.__hfTimelinesBuilding = true;
+    Object.defineProperty(document, "readyState", { configurable: true, get: () => "loading" });
+
+    await evaluateRuntime();
+    expect(window.__player).toBeUndefined();
+    expect(visibility(current, later)).toEqual(["hidden", "hidden"]);
+
+    delete (document as { readyState?: unknown }).readyState;
+    document.dispatchEvent(new Event("DOMContentLoaded"));
+    expect(window.__renderReady).toBe(false);
+    expect(visibility(current, later, poster)).toEqual(["hidden", "hidden", "visible"]);
+
+    window.__hfTimelinesBuilding = false;
+    window.dispatchEvent(new CustomEvent("hf-timelines-built"));
+    expect(window.__renderReady).toBe(true);
+    expect(visibility(current, later, poster)).toEqual(["visible", "hidden", "visible"]);
+  });
+
+  it("leaves nothing hidden when the runtime is evaluated a second time", async () => {
+    const root = mountRoot();
+    const current = timed(root, "div", "0");
+
+    await evaluateRuntime();
+    await evaluateRuntime();
+    // Paused and never sought: no later pass would lift a rule the second copy added.
+    expect(visibility(root, current)).toEqual(["visible", "visible"]);
+    expect(document.querySelectorAll("style[data-hf-first-pass-hide]")).toHaveLength(0);
+  });
+
+  it("grades media inside a clip once the first pass shows the clip, with no seek", async () => {
+    const getContext = vi.spyOn(HTMLCanvasElement.prototype, "getContext").mockReturnValue(null);
+    const scene = timed(mountRoot(), "div", "0");
+    // Untimed: the video inherits the scene's window, so no pass writes its visibility.
+    const video = document.createElement("video");
+    video.setAttribute(
+      HF_COLOR_GRADING_ATTR,
+      serializeHfColorGrading({ adjust: { exposure: 0.5 } }),
+    );
+    Object.defineProperty(video, "readyState", { value: HTMLMediaElement.HAVE_CURRENT_DATA });
+    Object.defineProperty(video, "videoWidth", { value: 640 });
+    Object.defineProperty(video, "videoHeight", { value: 360 });
+    scene.appendChild(video);
+
+    await evaluateRuntime();
+
+    expect(window.__renderReady).toBe(true);
+    expect(getContext.mock.calls.some(([type]) => String(type).startsWith("webgl"))).toBe(true);
+    getContext.mockRestore();
+  });
+});
diff --git a/packages/core/src/runtime/entry.ts b/packages/core/src/runtime/entry.ts
index 779668b0fe..58c86985c0 100644
--- a/packages/core/src/runtime/entry.ts
+++ b/packages/core/src/runtime/entry.ts
@@ -1,5 +1,6 @@
 import { initSandboxRuntimeModular } from "./init";
 import { installAuthoredOpacityCapture } from "./colorGrading";
+import { hideTimedClipsUntilFirstPass } from "./timedClipHide";
 import { fitTextFontSize } from "../text/fitTextFontSize";
 import { pretext } from "../text/pretext";
 import { assetUrl } from "./assetUrl";
@@ -28,6 +29,8 @@ type HyperframeWindow = Window & {
 // at script evaluation time, while the document is still parsing.
 installAuthoredOpacityCapture();
 
+hideTimedClipsUntilFirstPass();
+
 // Expose runtime helpers immediately so composition scripts can use them
 // before DOMContentLoaded (font sizing runs during script evaluation, and
 // getVariables is read by composition setup before the timeline is built).
diff --git a/packages/core/src/runtime/init.ts b/packages/core/src/runtime/init.ts
index 076554b167..2dfef746c7 100644
--- a/packages/core/src/runtime/init.ts
+++ b/packages/core/src/runtime/init.ts
@@ -1,6 +1,7 @@
 // fallow-ignore-file code-duplication complexity
 import { installRuntimeControlBridge, postRuntimeMessage, setRuntimeProtocolFps } from "./bridge";
 import { isInClipWindow } from "./clipWindow";
+import { revealTimedClipsAfterFirstPass } from "./timedClipHide";
 import { initRuntimeAnalytics, emitAnalyticsEvent } from "./analytics";
 import { injectCompositionCssVariables } from "./getVariables";
 import { createCssAdapter } from "./adapters/css";
@@ -2452,6 +2453,7 @@ export function initSandboxRuntimeModular(): void {
       0,
       timingRevision,
     );
+    let decidedTimedClip = false;
     for (const rawNode of visibilityNodes) {
       if (!isHtmlElement(rawNode)) continue;
 
@@ -2516,6 +2518,7 @@ export function initSandboxRuntimeModular(): void {
         }
       }
       rawNode.style.visibility = isVisibleNow ? "visible" : "hidden";
+      if (!isMediaElement(rawNode) && !isImageElement(rawNode)) decidedTimedClip = true;
       if (isVideoElement(rawNode) || isImageElement(rawNode)) {
         colorGradingRuntime?.setSourceVisibility(rawNode, isVisibleNow);
       }
@@ -2529,6 +2532,7 @@ export function initSandboxRuntimeModular(): void {
         timedClipDisplayNoneApplied.add(rawNode);
       }
     }
+    if (decidedTimedClip && revealTimedClipsAfterFirstPass()) colorGradingRuntime?.refresh();
     // Only when a `data-hidden` mutation actually moved something: the skips
     // this reschedule exists to re-run are what change the active set, so
     // firing it otherwise was an audible stop-and-restart across the whole mix
diff --git a/packages/core/src/runtime/timedClipHide.ts b/packages/core/src/runtime/timedClipHide.ts
new file mode 100644
index 0000000000..b590ec57b6
--- /dev/null
+++ b/packages/core/src/runtime/timedClipHide.ts
@@ -0,0 +1,34 @@
+// Hides timed non-media clips from script evaluation until the first visibility pass decides them;
+// before it, a paused page painted every clip at once. Media is left to init's media pass.
+// The rule and its flag live on the page, so every runtime copy shares them.
+const HIDE_ATTR = "data-hf-first-pass-hide";
+const HIDE_UNTIL_FIRST_PASS =
+  "[data-start]:not(video, audio, img) { visibility: hidden !important; }";
+
+type FirstPassWindow = Window & {
+  __hfFirstPassHidden?: boolean;
+  __hyperframeRuntimeBootstrapped?: boolean;
+};
+
+export function hideTimedClipsUntilFirstPass(): void {
+  if (typeof document === "undefined") return;
+  const win = window as FirstPassWindow;
+  // A runtime that already initialised may never run another pass to lift a new rule.
+  if (win.__hfFirstPassHidden || win.__hyperframeRuntimeBootstrapped) return;
+  const parent = document.head ?? document.documentElement;
+  if (!parent) return;
+  const style = document.createElement("style");
+  style.setAttribute(HIDE_ATTR, "");
+  style.textContent = HIDE_UNTIL_FIRST_PASS;
+  parent.appendChild(style);
+  win.__hfFirstPassHidden = true;
+}
+
+/** True when this call lifted the rule; callers then re-register what skipped hidden elements (grading). */
+export function revealTimedClipsAfterFirstPass(): boolean {
+  const win = window as FirstPassWindow;
+  if (!win.__hfFirstPassHidden) return false;
+  win.__hfFirstPassHidden = false;
+  for (const style of document.querySelectorAll(`style[${HIDE_ATTR}]`)) style.remove();
+  return true;
+}
diff --git a/packages/shader-transitions/src/capture.clone.test.ts b/packages/shader-transitions/src/capture.clone.test.ts
new file mode 100644
index 0000000000..c5746cc682
--- /dev/null
+++ b/packages/shader-transitions/src/capture.clone.test.ts
@@ -0,0 +1,20 @@
+// @vitest-environment jsdom
+import { describe, expect, it } from "vitest";
+import { forceSceneVisibleInClone } from "./capture.js";
+
+describe("forceSceneVisibleInClone", () => {
+  it("shows the scene and its timed clips while the runtime's first-pass hide rule is up", () => {
+    document.head.innerHTML =
+      "<style>[data-start]:not(video, audio, img) { visibility: hidden !important; }</style>";
+    document.body.innerHTML = '<div id="scene" data-start="0"><p data-start="0">Title</p></div>';
+    const scene = document.getElementById("scene") as HTMLElement;
+
+    forceSceneVisibleInClone(scene, document);
+
+    const title = scene.querySelector("p") as HTMLElement;
+    expect([scene, title].map((el) => getComputedStyle(el).visibility)).toEqual([
+      "visible",
+      "visible",
+    ]);
+  });
+});
diff --git a/packages/shader-transitions/src/capture.ts b/packages/shader-transitions/src/capture.ts
index 08aa82caff..31c30f2538 100644
--- a/packages/shader-transitions/src/capture.ts
+++ b/packages/shader-transitions/src/capture.ts
@@ -49,15 +49,15 @@ export interface CaptureSceneOptions {
   scale?: number;
 }
 
-function forceSceneVisibleInClone(source: HTMLElement, cloneDoc: Document): void {
+export function forceSceneVisibleInClone(source: HTMLElement, cloneDoc: Document): void {
   if (!source.id) return;
   const clone = cloneDoc.getElementById(source.id);
   if (!(clone instanceof HTMLElement)) return;
 
   clone.style.opacity = "1";
-  clone.style.visibility = "visible";
+  clone.style.setProperty("visibility", "visible", "important");
   clone.querySelectorAll<HTMLElement>("[data-start]").forEach((el) => {
-    el.style.visibility = "visible";
+    el.style.setProperty("visibility", "visible", "important");
   });
 }