@@ -34,6 +34,7 @@ const SETTINGS_PREFERENCES = [
   'automatic',
   'documentLanguageDetection',
   'topicSentenceDetection',
+  'watermarkRemovalEnabled',
   'paragraphContinuationDetection',
   'jevApiToken',
   'remoteKernelEnabled',
 
@@ -64,6 +64,7 @@ const DEFAULT_PREFERENCES = Object.freeze({
   automatic: true,
   documentLanguageDetection: false,
   topicSentenceDetection: false,
+  watermarkRemovalEnabled: false,
   paragraphContinuationDetection: false,
   jevApiToken: '',
   layoutVisible: false,
@@ -288,6 +289,7 @@ const VALIDATORS = {
   automatic: (value) => typeof value === 'boolean',
   documentLanguageDetection: (value) => typeof value === 'boolean',
   topicSentenceDetection: (value) => typeof value === 'boolean',
+  watermarkRemovalEnabled: (value) => typeof value === 'boolean',
   paragraphContinuationDetection: (value) => typeof value === 'boolean',
   jevApiToken: (value) => typeof value === 'string' && value.length <= 4096,
   remoteKernelEnabled: (value) => typeof value === 'boolean',
@@ -333,6 +335,7 @@ const VALIDATION_MESSAGES = {
   automatic: 'Invalid automatic translation preference',
   documentLanguageDetection: 'Invalid document language detection preference',
   topicSentenceDetection: 'Invalid topic sentence detection preference',
+  watermarkRemovalEnabled: 'Invalid watermark removal preference',
   paragraphContinuationDetection: 'Invalid paragraph continuation detection preference',
   jevApiToken: 'Invalid Jev API token preference',
   remoteKernelEnabled: 'Invalid remote kernel preference',
 
@@ -6,6 +6,8 @@ import { createReaderFit } from '../features/reader/reader-fit.mjs';
 import { createReaderZoom } from '../features/reader/reader-zoom.mjs';
 import { createReaderPinch } from '../features/reader/reader-pinch.mjs';
 import { createCanvasRendering } from '../features/reader/canvas-rendering.mjs';
+import { createWatermarkRemoval } from '../features/reader/watermark-removal.mjs';
+import { loadPDFRuntime } from '../features/reader/pdf-runtime.mjs';
 import { createReaderViewport } from '../features/reader/reader-viewport.mjs';
 import { createThumbnails } from '../features/reader/reader-thumbnails.mjs';
 import { createReaderPreview } from '../features/reader/reader-preview.mjs';
@@ -126,11 +128,22 @@ export function createReaderFeatures({
     }),
     view,
   });
+  const watermarkRemoval = createWatermarkRemoval({
+    session,
+    preferences,
+    loadRuntime: loadPDFRuntime,
+    // Frames drawn with the old setting are no longer right.
+    onToggle: () => {
+      canvasRendering.resetBitmaps();
+      void canvasRendering.renderPages(false, true);
+    },
+  });
   const canvasRendering = createCanvasRendering({
     renderState,
     session,
     motion,
     preferences,
+    watermarkRemoval,
     actions: createLazyPort({
       rootActions: () => rootActions,
       readerViewport: () => readerViewport,
 
@@ -11,6 +11,7 @@ export function createCanvasRendering({
   view,
   activity,
   actions,
+  watermarkRemoval,
 }) {
   function releaseCanvas(canvas) {
     if (!canvas) return;
@@ -133,7 +134,14 @@ export function createCanvasRendering({
       canvas.style.height = frame.height / dpr + 'px';
     }
     const cropKey = geometry.x + ':' + geometry.y + ':' + geometry.width + ':' + geometry.height;
-    renderState.canvasCache.set(canvas, { page, scale, dpr, geometry, cropKey });
+    renderState.canvasCache.set(canvas, {
+      page,
+      scale,
+      dpr,
+      geometry,
+      cropKey,
+      filter: frame.pdfFilter || '',
+    });
     canvas.paragraphGapState = gapState;
     if (gapState && previousGap?.source === source)
       animateParagraphGaps(canvas, previousGap, gapState, scale, geometry);
@@ -148,6 +156,9 @@ export function createCanvasRendering({
   }
 
   async function draw(page, canvas, scale, preview = false) {
+    // Pages with a watermark to hide are drawn, and cached, apart from the plain page.
+    const removal = watermarkRemoval?.enabled() ? await watermarkRemoval.renderOptions(page) : null,
+      filter = removal?.key || '';
     if (!activity.foreground.value || !canvas || !canvas.isConnected) return false;
     const number = Number(canvas.closest('.page')?.dataset.page);
     if (number && !renderState.renderWindow.value.has(number)) return false;
@@ -168,7 +179,8 @@ export function createCanvasRendering({
       cached?.page === page &&
       cached.scale === scale &&
       cached.dpr >= dpr &&
-      cached.cropKey === cropKey
+      cached.cropKey === cropKey &&
+      cached.filter === filter
     ) {
       if (current) {
         renderState.pageTasks.delete(canvas);
@@ -180,15 +192,16 @@ export function createCanvasRendering({
       current?.previewPage === page &&
       current.previewScale === scale &&
       current.previewDpr >= dpr &&
-      current.previewCrop === cropKey
+      current.previewCrop === cropKey &&
+      current.previewFilter === filter
     )
       return current.previewResult;
     if (current) {
       renderState.pageTasks.delete(canvas);
       current.cancel();
     }
     if (!renderState.bitmapIds.has(page)) renderState.bitmapIds.set(page, ++renderState.bitmapId);
-    const key = renderState.bitmapIds.get(page) + ':' + scale + ':' + dpr + ':' + cropKey,
+    const key = renderState.bitmapIds.get(page) + ':' + scale + ':' + dpr + ':' + cropKey + filter,
       reusable = renderState.bitmapFrames.get(key);
     if (reusable) {
       renderState.renderMetrics.cacheHits++;
@@ -199,7 +212,7 @@ export function createCanvasRendering({
     if (number && renderState.visiblePages.has(number) && !canvas.width) {
       const previewDpr = scrollPixelRatio(geometry.width, geometry.height, devicePixelRatio);
       const fallback = renderState.bitmapFrames.get(
-        renderState.bitmapIds.get(page) + ':' + scale + ':' + previewDpr + ':' + cropKey,
+        renderState.bitmapIds.get(page) + ':' + scale + ':' + previewDpr + ':' + cropKey + filter,
       );
       if (fallback) presentFrame(canvas, fallback, page, scale, previewDpr);
     }
@@ -208,16 +221,19 @@ export function createCanvasRendering({
     frame.width = Math.ceil(geometry.width * dpr);
     frame.height = Math.ceil(geometry.height * dpr);
     frame.pdfFrame = geometry;
+    frame.pdfFilter = filter;
     const task = page.render({
       canvasContext: frame.getContext('2d'),
       viewport,
       transform: [dpr, 0, 0, dpr, -geometry.x * dpr, -geometry.y * dpr],
+      ...removal?.render,
     });
     Object.assign(task, {
       previewPage: page,
       previewScale: scale,
       previewDpr: dpr,
       previewCrop: cropKey,
+      previewFilter: filter,
     });
     renderState.pageTasks.set(canvas, task);
     task.onContinue = (continuation) => {