diff --git a/backend/__tests__/integration/revealMode.test.js b/backend/__tests__/integration/revealMode.test.js
new file mode 100644
index 00000000..802517fe
--- /dev/null
+++ b/backend/__tests__/integration/revealMode.test.js
@@ -0,0 +1,402 @@
+/**
+ * Reveal mode integration tests (#838).
+ *
+ * Pins the contract:
+ *  - effective visibility is computed at request time (isGalleryHidden):
+ *    reveal_at in the past opens the gate even before the scheduler stamps
+ *  - /photos returns the event shell with photos: [] + hidden_until_reveal
+ *    for plain guests; slideshow / client / admin-preview see everything
+ *  - image + download endpoints 403 with GALLERY_HIDDEN for plain guests
+ *  - the guest upload route is NOT gated (uploading while hidden is the point)
+ *  - the scheduler stamps revealed_at for due events, exactly once
+ *  - POST /events/:id/reveal stamps revealed_at (idempotent, 400 when the
+ *    mode is off); re-enabling reveal_mode clears revealed_at (re-hide)
+ */
+
+const request = require('supertest');
+const express = require('express');
+const cookieParser = require('cookie-parser');
+const bcrypt = require('bcrypt');
+const jwt = require('jsonwebtoken');
+
+const { bootCrmDb, seedMinimal } = require('./helpers/crmDb');
+
+process.env.JWT_SECRET = process.env.JWT_SECRET || 'reveal-test-secret';
+
+const SLUG = 'reveal-test-event';
+
+describe('Reveal mode (#838)', () => {
+  let db;
+  let cleanup;
+  let app;
+  let eventId;
+  let photoIds;
+  let adminToken;
+  const { isGalleryHidden } = require('../../src/utils/revealMode');
+
+  const galleryToken = (extra = {}) => jwt.sign(
+    { eventId, eventSlug: SLUG, type: 'gallery', ...extra },
+    process.env.JWT_SECRET,
+    { expiresIn: '1h', issuer: 'picpeak-auth' }
+  );
+
+  beforeAll(async () => {
+    ({ db, cleanup } = await bootCrmDb());
+    await seedMinimal(db);
+
+    const inserted = await db('events').insert({
+      slug: SLUG,
+      event_type: 'wedding',
+      event_name: 'Reveal Test',
+      event_date: '2026-08-01',
+      host_email: 'host@example.com',
+      admin_email: 'admin@example.com',
+      password_hash: 'x',
+      share_link: `/gallery/${SLUG}/share`,
+      share_token: 'reveal-test-share',
+      expires_at: new Date(Date.now() + 7 * 24 * 3600 * 1000).toISOString(),
+      is_active: 1,
+      is_archived: 0,
+      is_draft: 0,
+      allow_user_uploads: 1,
+      reveal_mode: 1,
+      created_at: new Date().toISOString(),
+    }).returning('id');
+    eventId = inserted[0]?.id ?? inserted[0];
+
+    photoIds = [];
+    for (let i = 0; i < 2; i++) {
+      const p = await db('photos').insert({
+        event_id: eventId,
+        filename: `photo-${i}.jpg`,
+        path: `events/reveal/${i}.jpg`,
+        type: 'individual',
+        uploaded_at: new Date().toISOString(),
+      }).returning('id');
+      photoIds.push(p[0]?.id ?? p[0]);
+    }
+
+    // Super admin for the admin routes.
+    const superRole = await db('roles').where({ name: 'super_admin' }).first();
+    const [rootId] = await db('admin_users').insert({
+      username: 'reveal-admin',
+      email: 'reveal-admin@example.com',
+      password_hash: await bcrypt.hash('RevealAdmin123', 4),
+      role_id: superRole.id,
+      is_active: 1,
+      created_at: new Date(),
+      updated_at: new Date(),
+    }).returning('id').then((r) => [r[0]?.id || r[0]]);
+    adminToken = jwt.sign(
+      { id: rootId, username: 'reveal-admin', type: 'admin', role: 'super_admin', loginTime: Date.now() },
+      process.env.JWT_SECRET,
+      { expiresIn: '1h', issuer: 'picpeak-auth' }
+    );
+
+    app = express();
+    app.use(express.json());
+    app.use(cookieParser());
+    app.use('/api/gallery', require('../../src/routes/gallery'));
+    app.use('/api/secure-images', require('../../src/routes/secureImages'));
+    app.use('/api/images', require('../../src/routes/protectedImages'));
+    app.use('/api/gallery', require('../../src/routes/galleryFeedback'));
+    app.use('/api/admin/events', require('../../src/routes/adminEvents'));
+  }, 120000);
+
+  afterAll(async () => {
+    if (cleanup) await cleanup();
+  });
+
+  describe('effective visibility math (isGalleryHidden)', () => {
+    const base = { reveal_mode: true, revealed_at: null, reveal_at: null };
+    it('is hidden while armed and unrevealed, visible otherwise', () => {
+      expect(isGalleryHidden({ ...base })).toBe(true);
+      expect(isGalleryHidden({ ...base, reveal_mode: false })).toBe(false);
+      expect(isGalleryHidden({ ...base, revealed_at: new Date() })).toBe(false);
+      // reveal_at in the past opens the gate WITHOUT any stamp — time-exact.
+      expect(isGalleryHidden({ ...base, reveal_at: new Date(Date.now() - 60_000) })).toBe(false);
+      expect(isGalleryHidden({ ...base, reveal_at: new Date(Date.now() + 60_000) })).toBe(true);
+      // SQLite 0/1 booleans
+      expect(isGalleryHidden({ reveal_mode: 1, revealed_at: null, reveal_at: null })).toBe(true);
+      expect(isGalleryHidden({ reveal_mode: 0, revealed_at: null, reveal_at: null })).toBe(false);
+    });
+  });
+
+  describe('gallery routes while hidden', () => {
+    it('/photos gives plain guests the shell with no photos and the flag', async () => {
+      const res = await request(app)
+        .get(`/api/gallery/${SLUG}/photos`)
+        .set('Authorization', `Bearer ${galleryToken()}`);
+      expect(res.status).toBe(200);
+      expect(res.body.hidden_until_reveal).toBe(true);
+      expect(res.body.photos).toEqual([]);
+      expect(res.body.categories).toEqual([]);
+      expect(res.body.event.event_name).toBe('Reveal Test');
+    });
+
+    it('/photos serves the slideshow token everything (surprise beamer)', async () => {
+      const res = await request(app)
+        .get(`/api/gallery/${SLUG}/photos`)
+        .set('Authorization', `Bearer ${galleryToken({ accessLevel: 'slideshow' })}`);
+      expect(res.status).toBe(200);
+      expect(res.body.hidden_until_reveal).toBe(false);
+      expect(res.body.photos).toHaveLength(2);
+    });
+
+    it('/photos serves client access everything (host review)', async () => {
+      const res = await request(app)
+        .get(`/api/gallery/${SLUG}/photos`)
+        .set('Authorization', `Bearer ${galleryToken({ accessLevel: 'client' })}`);
+      expect(res.status).toBe(200);
+      expect(res.body.hidden_until_reveal).toBe(false);
+      expect(res.body.photos).toHaveLength(2);
+    });
+
+    it('/photos serves the admin preview everything', async () => {
+      const res = await request(app)
+        .get(`/api/gallery/${SLUG}/photos?preview=${encodeURIComponent(adminToken)}`)
+        .set('Authorization', `Bearer ${galleryToken()}`);
+      expect(res.status).toBe(200);
+      expect(res.body.hidden_until_reveal).toBe(false);
+      expect(res.body.photos).toHaveLength(2);
+    });
+
+    it('image and download endpoints 403 with GALLERY_HIDDEN for plain guests', async () => {
+      for (const url of [
+        `/api/gallery/${SLUG}/thumbnail/${photoIds[0]}`,
+        `/api/gallery/${SLUG}/photo/${photoIds[0]}`,
+        `/api/gallery/${SLUG}/download/${photoIds[0]}`,
+        `/api/gallery/${SLUG}/download-all`,
+        `/api/gallery/${SLUG}/stats`,
+        `/api/gallery/${SLUG}/hero/${photoIds[0]}`,
+      ]) {
+        const res = await request(app).get(url).set('Authorization', `Bearer ${galleryToken()}`);
+        expect(`${url}:${res.status}`).toBe(`${url}:403`);
+        expect(res.body.code).toBe('GALLERY_HIDDEN');
+      }
+    });
+
+    it('image endpoints are NOT reveal-blocked for the slideshow token', async () => {
+      const res = await request(app)
+        .get(`/api/gallery/${SLUG}/thumbnail/${photoIds[0]}`)
+        .set('Authorization', `Bearer ${galleryToken({ accessLevel: 'slideshow' })}`);
+      // The seeded file doesn't exist on disk, so anything but the reveal
+      // gate's 403 is fine here.
+      expect(res.body.code).not.toBe('GALLERY_HIDDEN');
+    });
+
+    it('/info exposes the effective hidden state without auth', async () => {
+      const res = await request(app).get(`/api/gallery/${SLUG}/info`);
+      expect(res.status).toBe(200);
+      expect(res.body.hidden_until_reveal).toBe(true);
+    });
+
+    it('the guest upload route is not gated', async () => {
+      const res = await request(app)
+        .post(`/api/gallery/${eventId}/upload`)
+        .set('Authorization', `Bearer ${galleryToken()}`)
+        .send({});
+      // Fails later for other reasons (no multipart body) — but never on the
+      // reveal gate.
+      expect(res.body.code).not.toBe('GALLERY_HIDDEN');
+    });
+
+    it('legacy protected-image routes are reveal-gated for plain guests', async () => {
+      for (const [method, url] of [
+        ['get', `/api/images/${SLUG}/photo/${photoIds[0]}/view`],
+        ['post', `/api/images/${SLUG}/photo/${photoIds[0]}/generate-secure-token`],
+        ['post', `/api/images/${SLUG}/photo/${photoIds[0]}/generate-url`],
+      ]) {
+        const res = await request(app)[method](url).set('Authorization', `Bearer ${galleryToken()}`);
+        expect(`${url}:${res.status}`).toBe(`${url}:403`);
+        expect(res.body.code).toBe('GALLERY_HIDDEN');
+      }
+    });
+
+    it('feedback endpoints are reveal-gated; my-feedback degrades to empty', async () => {
+      // Feedback must be enabled for the routes to get past their own gate.
+      await db('event_feedback_settings').insert({
+        event_id: eventId, feedback_enabled: 1, allow_likes: 1,
+        created_at: new Date().toISOString(), updated_at: new Date().toISOString(),
+      });
+      const getRes = await request(app)
+        .get(`/api/gallery/${SLUG}/photos/${photoIds[0]}/feedback`)
+        .set('Authorization', `Bearer ${galleryToken()}`);
+      expect(getRes.status).toBe(403);
+      expect(getRes.body.code).toBe('GALLERY_HIDDEN');
+
+      const postRes = await request(app)
+        .post(`/api/gallery/${SLUG}/photos/${photoIds[0]}/feedback`)
+        .set('Authorization', `Bearer ${galleryToken()}`)
+        .send({ feedback_type: 'like' });
+      expect(postRes.status).toBe(403);
+      expect(postRes.body.code).toBe('GALLERY_HIDDEN');
+
+      const mine = await request(app)
+        .get(`/api/gallery/${SLUG}/my-feedback`)
+        .set('Authorization', `Bearer ${galleryToken()}`);
+      expect(mine.status).toBe(200);
+      expect(mine.body).toEqual([]);
+    });
+
+    it('secure-image token minting is reveal-gated for plain guests', async () => {
+      const res = await request(app)
+        .post(`/api/secure-images/${SLUG}/generate-token`)
+        .set('Authorization', `Bearer ${galleryToken()}`)
+        .send({ photoId: photoIds[0] });
+      expect(res.status).toBe(403);
+      expect(res.body.code).toBe('GALLERY_HIDDEN');
+    });
+
+    it('customer-portal tokens (via:customer, no accessLevel) bypass reveal mode', async () => {
+      const acct = await db('customer_accounts').insert({
+        email: 'portal-customer@example.com',
+        password_hash: 'x',
+        is_active: 1,
+        created_at: new Date().toISOString(),
+        updated_at: new Date().toISOString(),
+      }).returning('id');
+      const customerId = acct[0]?.id ?? acct[0];
+      await db('event_customer_assignments').insert({
+        event_id: eventId,
+        customer_account_id: customerId,
+      });
+
+      const res = await request(app)
+        .get(`/api/gallery/${SLUG}/photos`)
+        .set('Authorization', `Bearer ${galleryToken({ via: 'customer', customerId })}`);
+      expect(res.status).toBe(200);
+      expect(res.body.hidden_until_reveal).toBe(false);
+      expect(res.body.photos).toHaveLength(2);
+    });
+
+    it('a reveal_at in the past opens the gate without any stamp', async () => {
+      await db('events').where('id', eventId).update({ reveal_at: new Date(Date.now() - 60_000).toISOString() });
+      const res = await request(app)
+        .get(`/api/gallery/${SLUG}/photos`)
+        .set('Authorization', `Bearer ${galleryToken()}`);
+      expect(res.body.hidden_until_reveal).toBe(false);
+      expect(res.body.photos).toHaveLength(2);
+      await db('events').where('id', eventId).update({ reveal_at: null });
+    });
+  });
+
+  describe('scheduler and admin reveal', () => {
+    it('the scheduler stamps revealed_at for due events exactly once', async () => {
+      const revealAt = new Date(Date.now() - 5 * 60_000);
+      await db('events').where('id', eventId).update({ reveal_at: revealAt.toISOString(), revealed_at: null });
+
+      const { checkScheduledReveals } = require('../../src/services/revealScheduler');
+      await checkScheduledReveals();
+
+      const asMs = (v) => new Date(v).getTime();
+      const row = await db('events').where('id', eventId).first();
+      expect(row.revealed_at).not.toBeNull();
+      expect(asMs(row.revealed_at)).toBe(revealAt.getTime());
+      expect(row.reveal_at).toBeNull(); // schedule consumed, like "Reveal now"
+
+      // Second pass no-ops (revealed_at already set).
+      await checkScheduledReveals();
+      const again = await db('events').where('id', eventId).first();
+      expect(asMs(again.revealed_at)).toBe(revealAt.getTime());
+
+      await db('events').where('id', eventId).update({ reveal_at: null, revealed_at: null });
+    });
+
+    it('POST /:id/reveal stamps revealed_at, clears the schedule, and is idempotent', async () => {
+      await db('events').where('id', eventId).update({ reveal_at: new Date(Date.now() + 3600_000).toISOString() });
+      const res = await request(app)
+        .post(`/api/admin/events/${eventId}/reveal`)
+        .set('Authorization', `Bearer ${adminToken}`);
+      expect(res.status).toBe(200);
+      expect(res.body.revealed_at).toBeTruthy();
+      // "Reveal now" consumes the pending schedule.
+      const cleared = await db('events').where('id', eventId).first();
+      expect(cleared.reveal_at).toBeNull();
+
+      const first = res.body.revealed_at;
+      const res2 = await request(app)
+        .post(`/api/admin/events/${eventId}/reveal`)
+        .set('Authorization', `Bearer ${adminToken}`);
+      expect(res2.status).toBe(200);
+      expect(res2.body.revealed_at).toBe(first);
+
+      // Guests see photos now.
+      const gallery = await request(app)
+        .get(`/api/gallery/${SLUG}/photos`)
+        .set('Authorization', `Bearer ${galleryToken()}`);
+      expect(gallery.body.hidden_until_reveal).toBe(false);
+      expect(gallery.body.photos).toHaveLength(2);
+    });
+
+    it('re-enabling reveal_mode clears revealed_at (re-hide)', async () => {
+      await db('events').where('id', eventId).update({ reveal_mode: 0 });
+      const res = await request(app)
+        .put(`/api/admin/events/${eventId}`)
+        .set('Authorization', `Bearer ${adminToken}`)
+        .send({ reveal_mode: true });
+      expect(res.status).toBe(200);
+
+      const row = await db('events').where('id', eventId).first();
+      expect(row.revealed_at).toBeNull();
+
+      const gallery = await request(app)
+        .get(`/api/gallery/${SLUG}/photos`)
+        .set('Authorization', `Bearer ${galleryToken()}`);
+      expect(gallery.body.hidden_until_reveal).toBe(true);
+    });
+
+    it('scheduling a FUTURE reveal on a revealed gallery re-arms hiding', async () => {
+      // State: revealed (previous tests). Saving a future schedule re-hides.
+      await db('events').where('id', eventId).update({ revealed_at: new Date().toISOString() });
+      const res = await request(app)
+        .put(`/api/admin/events/${eventId}`)
+        .set('Authorization', `Bearer ${adminToken}`)
+        .send({ reveal_mode: true, reveal_at: new Date(Date.now() + 3600_000).toISOString() });
+      expect(res.status).toBe(200);
+      const row = await db('events').where('id', eventId).first();
+      expect(row.revealed_at).toBeNull();
+
+      const gallery = await request(app)
+        .get(`/api/gallery/${SLUG}/photos`)
+        .set('Authorization', `Bearer ${galleryToken()}`);
+      expect(gallery.body.hidden_until_reveal).toBe(true);
+      await db('events').where('id', eventId).update({ reveal_at: null });
+    });
+
+    it('re-arming without a schedule clears a stale PAST reveal_at', async () => {
+      // Legacy/partial-API state: revealed with the old past schedule still
+      // stored. {reveal_mode:false} then {reveal_mode:true} without
+      // reveal_at must re-hide, not instantly re-open via the stale date.
+      await db('events').where('id', eventId).update({
+        reveal_mode: 0,
+        revealed_at: new Date().toISOString(),
+        reveal_at: new Date(Date.now() - 3600_000).toISOString(),
+      });
+      const res = await request(app)
+        .put(`/api/admin/events/${eventId}`)
+        .set('Authorization', `Bearer ${adminToken}`)
+        .send({ reveal_mode: true });
+      expect(res.status).toBe(200);
+
+      const row = await db('events').where('id', eventId).first();
+      expect(row.revealed_at).toBeNull();
+      expect(row.reveal_at).toBeNull();
+
+      const gallery = await request(app)
+        .get(`/api/gallery/${SLUG}/photos`)
+        .set('Authorization', `Bearer ${galleryToken()}`);
+      expect(gallery.body.hidden_until_reveal).toBe(true);
+      expect(gallery.body.photos).toEqual([]);
+    });
+
+    it('POST /:id/reveal 400s while reveal mode is off', async () => {
+      await db('events').where('id', eventId).update({ reveal_mode: 0, revealed_at: null });
+      const res = await request(app)
+        .post(`/api/admin/events/${eventId}/reveal`)
+        .set('Authorization', `Bearer ${adminToken}`);
+      expect(res.status).toBe(400);
+      await db('events').where('id', eventId).update({ reveal_mode: 1 });
+    });
+  });
+});
diff --git a/backend/migrations/core/165_add_reveal_mode.js b/backend/migrations/core/165_add_reveal_mode.js
new file mode 100644
index 00000000..9e489cb6
--- /dev/null
+++ b/backend/migrations/core/165_add_reveal_mode.js
@@ -0,0 +1,44 @@
+/**
+ * Reveal mode (#838): hide the gallery from guests until a manual or
+ * scheduled reveal — guests can still upload, the host/admin/slideshow see
+ * everything.
+ *
+ * - events.reveal_mode: the per-event toggle (only meaningful together with
+ *   allow_user_uploads; off by default so nothing changes for existing events)
+ * - events.reveal_at: optional scheduled reveal time. Effective visibility is
+ *   computed at REQUEST time (reveal_at <= now opens the gate even before the
+ *   scheduler runs), the minutely scheduler only stamps revealed_at durably.
+ * - events.revealed_at: set by "Reveal now" or the scheduler; NULL while
+ *   hidden. Re-enabling reveal_mode clears it (re-hide).
+ */
+
+// Each column guarded independently: a partially applied prior run (or a
+// fork that added one of them) must not leave the others missing — the
+// routes select all three.
+exports.up = async function (knex) {
+  if (!(await knex.schema.hasColumn('events', 'reveal_mode'))) {
+    await knex.schema.alterTable('events', (table) => {
+      table.boolean('reveal_mode').defaultTo(false);
+    });
+  }
+  if (!(await knex.schema.hasColumn('events', 'reveal_at'))) {
+    await knex.schema.alterTable('events', (table) => {
+      table.timestamp('reveal_at').nullable();
+    });
+  }
+  if (!(await knex.schema.hasColumn('events', 'revealed_at'))) {
+    await knex.schema.alterTable('events', (table) => {
+      table.timestamp('revealed_at').nullable();
+    });
+  }
+};
+
+exports.down = async function (knex) {
+  for (const column of ['revealed_at', 'reveal_at', 'reveal_mode']) {
+    if (await knex.schema.hasColumn('events', column)) {
+      await knex.schema.alterTable('events', (table) => {
+        table.dropColumn(column);
+      });
+    }
+  }
+};
diff --git a/backend/server.js b/backend/server.js
index 346a71f2..aa027789 100644
--- a/backend/server.js
+++ b/backend/server.js
@@ -20,6 +20,7 @@ const path = require('path');
 const { initializeDatabase, db } = require('./src/database/db');
 const { startFileWatcher } = require('./src/services/fileWatcher');
 const { startExpirationChecker } = require('./src/services/expirationChecker');
+const { startRevealScheduler } = require('./src/services/revealScheduler');
 const { startInvoiceScheduler } = require('./src/services/invoiceSchedulerService');
 const { initializeTransporter, startEmailQueueProcessor } = require('./src/services/emailProcessor');
 const { startBackupService } = require('./src/services/backupService');
@@ -903,6 +904,8 @@ async function startServer() {
     
     // Start expiration checker
     startExpirationChecker();
+    // Reveal-mode scheduler (#838): minutely stamp for scheduled reveals.
+    startRevealScheduler();
     // CRM invoice scheduler: hourly tick to flush scheduled-send invoices
     // + run the overdue reminder ladder. No-op when the `bills` feature
     // flag is OFF (the service short-circuits on empty result sets).
diff --git a/backend/src/routes/adminEvents/crud.js b/backend/src/routes/adminEvents/crud.js
index 85f4f295..60fe45a8 100644
--- a/backend/src/routes/adminEvents/crud.js
+++ b/backend/src/routes/adminEvents/crud.js
@@ -1177,6 +1177,9 @@ module.exports = (router) => {
     body('welcome_message').optional({ nullable: true, checkFalsy: true }).trim(),
     body('color_theme').optional({ nullable: true }),
     body('allow_user_uploads').optional().isBoolean(),
+    // Reveal mode (#838): hide the gallery from guests until reveal.
+    body('reveal_mode').optional().isBoolean(),
+    body('reveal_at').optional({ nullable: true, checkFalsy: true }).isISO8601(),
     // Migration 143 — per-event reminder overrides. All three are
     // optional; nullable values are accepted so admins can clear an
     // override (e.g. drop a custom offset back to the global default).
@@ -1489,6 +1492,39 @@ module.exports = (router) => {
         }
       }
 
+      // Reveal mode (#838). Turning the toggle ON from off clears
+      // revealed_at, so a gallery can be re-hidden after a reveal;
+      // reveal_at accepts null/'' to drop a schedule.
+      if (Object.prototype.hasOwnProperty.call(updates, 'reveal_mode')) {
+        const nextRevealMode = parseBooleanInput(updates.reveal_mode, false);
+        updates.reveal_mode = formatBoolean(nextRevealMode);
+        const wasOn = event.reveal_mode === true || event.reveal_mode === 1 || event.reveal_mode === '1';
+        if (nextRevealMode && !wasOn) {
+          updates.revealed_at = null;
+          // A stale PAST schedule from a previous cycle would instantly
+          // re-open the gate on re-arm. Only bites partial API updates —
+          // isGalleryHidden() with the stamp cleared tells us whether the
+          // stored schedule still hides anything.
+          const { isGalleryHidden } = require('../../utils/revealMode');
+          if (!Object.prototype.hasOwnProperty.call(updates, 'reveal_at')
+              && event.reveal_at
+              && !isGalleryHidden({ reveal_mode: true, revealed_at: null, reveal_at: event.reveal_at })) {
+            updates.reveal_at = null;
+          }
+        }
+      }
+      if (Object.prototype.hasOwnProperty.call(updates, 'reveal_at')) {
+        // ISO string, not a Date object — the SQLite driver stringifies raw
+        // Dates uselessly; ISO round-trips on both engines.
+        updates.reveal_at = updates.reveal_at ? new Date(updates.reveal_at).toISOString() : null;
+        // Scheduling a FUTURE reveal on an already-revealed gallery re-arms
+        // hiding — that's the only way this state can be reached, since
+        // "Reveal now" and the scheduler both clear/consume the schedule.
+        if (updates.reveal_at && new Date(updates.reveal_at) > new Date() && event.revealed_at) {
+          updates.revealed_at = null;
+        }
+      }
+
       // Handle client access fields (#172)
       if (Object.prototype.hasOwnProperty.call(updates, 'client_access_enabled')) {
         updates.client_access_enabled = formatBoolean(updates.client_access_enabled);
@@ -1543,6 +1579,58 @@ module.exports = (router) => {
   });
 
   // Delete event
+  // Reveal now (#838): stamp revealed_at so the gallery opens for guests
+  // immediately. Idempotent — revealing an already-revealed event no-ops.
+  router.post('/:id/reveal', adminAuth, requirePermission('events.edit'), requireEventOwnership, async (req, res) => {
+    try {
+      const { id } = req.params;
+      const event = await db('events').where('id', id).first();
+      if (!event) {
+        return res.status(404).json({ error: 'Event not found' });
+      }
+      const isOn = event.reveal_mode === true || event.reveal_mode === 1 || event.reveal_mode === '1';
+      if (!isOn) {
+        return res.status(400).json({ error: 'Reveal mode is not enabled for this event' });
+      }
+
+      const now = new Date().toISOString();
+      // Also clear a pending schedule — "reveal now" makes it obsolete, and
+      // a stale future reveal_at would re-arm hiding on the next form save.
+      const stamped = await db('events')
+        .where('id', id)
+        .whereNull('revealed_at')
+        .update({ revealed_at: now, reveal_at: null });
+
+      if (stamped === 1) {
+        await logActivity('gallery_revealed', { scheduled: false }, id, {
+          type: 'admin', id: req.admin.id, name: req.admin.username,
+        });
+        try {
+          await require('../../services/workflows').emitWorkflowEvent('gallery.revealed', {
+            entityType: 'event',
+            entityId: parseInt(id, 10),
+            dedupSuffix: String(new Date(now).getTime()),
+            payload: {
+              eventId: parseInt(id, 10),
+              slug: event.slug,
+              eventName: event.event_name,
+              revealedAt: now,
+              scheduled: false,
+            },
+          });
+        } catch (e) {
+          logger.warn('Failed to emit gallery.revealed workflow event', { eventId: id, error: e.message });
+        }
+      }
+
+      const fresh = await db('events').where('id', id).first();
+      res.json({ message: 'Gallery revealed', revealed_at: fresh.revealed_at });
+    } catch (error) {
+      logger.error('Failed to reveal gallery:', error);
+      res.status(500).json({ error: 'Failed to reveal gallery' });
+    }
+  });
+
   router.delete('/:id', adminAuth, requirePermission('events.delete'), requireEventOwnership, async (req, res) => {
     try {
       const { id } = req.params;
diff --git a/backend/src/routes/gallery.js b/backend/src/routes/gallery.js
index 59d3771b..61cd4d29 100644
--- a/backend/src/routes/gallery.js
+++ b/backend/src/routes/gallery.js
@@ -28,6 +28,7 @@ const { resolvePhotoFilePath } = require('../services/photoResolver');
 const { getEventCategoriesOrdered } = require('../utils/categoryOrder');
 const { getEventShareToken, resolveShareIdentifier, buildShareLinkVariants } = require('../services/shareLinkService');
 const { handleAsync, errorResponse } = require('../utils/routeHelpers');
+const { isGalleryHidden, guestBlockedByReveal, blockHiddenGallery } = require('../utils/revealMode');
 const { NotFoundError } = require('../utils/errors');
 const { ensureThumbnail, ensureHeroImage, ensurePreviewImage, withLocalCopy } = require('../services/imageProcessor');
 const downloadZipService = require('../services/downloadZipService');
@@ -205,6 +206,9 @@ router.get('/:slug/info', async (req, res) => {
         'share_token',
         'allow_downloads',
         'allow_user_uploads',
+        'reveal_mode',
+        'reveal_at',
+        'revealed_at',
         'disable_right_click',
         'watermark_downloads',
         'watermark_text',
@@ -275,6 +279,10 @@ router.get('/:slug/info', async (req, res) => {
       color_theme: event.color_theme,
       allow_downloads: !(event.allow_downloads === false || event.allow_downloads === 0 || event.allow_downloads === '0'),
       allow_user_uploads: event.allow_user_uploads === true || event.allow_user_uploads === 1 || event.allow_user_uploads === '1',
+      // Reveal mode (#838): effective hidden state (computed, time-exact) so
+      // the landing page can hint at the reveal before login too.
+      hidden_until_reveal: isGalleryHidden(event),
+      reveal_at: isGalleryHidden(event) ? (event.reveal_at || null) : null,
       disable_right_click: event.disable_right_click === true || event.disable_right_click === 1 || event.disable_right_click === '1',
       watermark_downloads: event.watermark_downloads === true || event.watermark_downloads === 1 || event.watermark_downloads === '1',
       watermark_text: event.watermark_text,
@@ -622,8 +630,15 @@ router.get('/:slug/photos', verifyGalleryAccess, resolveGuest, async (req, res)
       photosQuery = photosQuery.orderBy('photos.uploaded_at', sortOrder);
     }
 
+    // Reveal mode (#838): while the gallery is hidden, plain guests get
+    // the event shell with an empty photo/category set plus the
+    // hidden_until_reveal flag — the frontend renders the upload-only view
+    // from it. Slideshow, client access and the admin preview bypass
+    // (guestBlockedByReveal). Enforced here, not just in the UI.
+    const hiddenForGuest = guestBlockedByReveal(req);
+
     // Execute the query
-    let photos = await photosQuery;
+    let photos = hiddenForGuest ? [] : await photosQuery;
     
     // Apply filtering if requested (supports global stats + per-guest interactions)
     if (filter) {
@@ -749,7 +764,7 @@ router.get('/:slug/photos', verifyGalleryAccess, resolveGuest, async (req, res)
     
     // Get actual categories used by photos in this event
     // This includes both global categories and event-specific ones
-    const usedCategoryIds = await db('photos')
+    const usedCategoryIds = hiddenForGuest ? [] : await db('photos')
       .where('event_id', req.event.id)
       .whereNotNull('category_id')
       .distinct('category_id')
@@ -853,6 +868,9 @@ router.get('/:slug/photos', verifyGalleryAccess, resolveGuest, async (req, res)
         hero_photo_id: req.event.hero_photo_id,
         allow_downloads: req.event.allow_downloads !== false,
         allow_user_uploads: req.event.allow_user_uploads === true,
+        // Reveal mode (#838): armed flag lets an open VISIBLE gallery keep
+        // polling so a re-hide propagates without a manual reload.
+        reveal_armed: req.event.reveal_mode === true || req.event.reveal_mode === 1 || req.event.reveal_mode === '1',
         disable_right_click: req.event.disable_right_click === true,
         watermark_downloads: req.event.watermark_downloads === true,
         watermark_text: req.event.watermark_text,
@@ -872,6 +890,10 @@ router.get('/:slug/photos', verifyGalleryAccess, resolveGuest, async (req, res)
         use_original_filenames: useOriginalFilenames,
         ...protectionSettings
       },
+      // Reveal mode (#838): the guest UI switches to the upload-only view
+      // on this flag; reveal_at lets it show the scheduled time.
+      hidden_until_reveal: hiddenForGuest,
+      reveal_at: hiddenForGuest ? (req.event.reveal_at || null) : undefined,
       categories: categories,
       photos: photos.map(photo => {
         const useJwtUrl = (protectionSettings.protection_level === 'basic' || protectionSettings.protection_level === 'standard');
@@ -1006,8 +1028,9 @@ router.patch('/:slug/photos/visibility/bulk', verifyGalleryAccess, async (req, r
   }
 });
 
+
 // Download single photo
-router.get('/:slug/download/:photoId', verifyGalleryAccess, denySlideshowToken, async (req, res) => {
+router.get('/:slug/download/:photoId', verifyGalleryAccess, denySlideshowToken, blockHiddenGallery, async (req, res) => {
   try {
     const { photoId } = req.params;
 
@@ -1128,7 +1151,7 @@ router.get('/:slug/download/:photoId', verifyGalleryAccess, denySlideshowToken,
 });
 
 // Download all photos as ZIP
-router.get('/:slug/download-all', verifyGalleryAccess, denySlideshowToken, async (req, res) => {
+router.get('/:slug/download-all', verifyGalleryAccess, denySlideshowToken, blockHiddenGallery, async (req, res) => {
   try {
     // Check if downloads are allowed for this event
     if (req.event.allow_downloads === false) {
@@ -1313,7 +1336,7 @@ router.get('/:slug/download-all', verifyGalleryAccess, denySlideshowToken, async
 });
 
 // Download selected photos as ZIP
-router.post('/:slug/download-selected', verifyGalleryAccess, denySlideshowToken, async (req, res) => {
+router.post('/:slug/download-selected', verifyGalleryAccess, denySlideshowToken, blockHiddenGallery, async (req, res) => {
   try {
     // Check if downloads are allowed for this event
     if (req.event.allow_downloads === false) {
@@ -1437,6 +1460,7 @@ router.post('/:slug/download-selected', verifyGalleryAccess, denySlideshowToken,
 // View single photo (with watermark if enabled)
 router.get('/:slug/photo/:photoId',
   verifyGalleryAccess,
+  blockHiddenGallery,
   async (req, res) => {
     try {
       const { photoId } = req.params;
@@ -1669,6 +1693,7 @@ router.get('/:slug/photo/:photoId',
 // Serve thumbnail
 router.get('/:slug/thumbnail/:photoId',
   verifyGalleryAccess,
+  blockHiddenGallery,
   async (req, res) => {
     try {
       const { photoId } = req.params;
@@ -1760,6 +1785,9 @@ router.get('/:slug/thumbnail/:photoId',
 // Serve hero-optimized image (1920x1080 for full-width hero sections)
 router.get('/:slug/hero/:photoId',
   verifyGalleryAccess,
+  // Reveal-gated too: this route serves a 1920px derivative of ANY photo id,
+  // not just the chosen hero — an open bypass while hidden (review round 1).
+  blockHiddenGallery,
   async (req, res) => {
     try {
       const { photoId } = req.params;
@@ -1858,6 +1886,7 @@ router.get('/:slug/hero/:photoId',
 // guest would see on the full original.
 router.get('/:slug/preview/:photoId',
   verifyGalleryAccess,
+  blockHiddenGallery,
   async (req, res) => {
     try {
       const { photoId } = req.params;
@@ -1967,7 +1996,7 @@ router.get('/:slug/feedback-settings', verifyGalleryAccess, async (req, res) =>
 });
 
 // Get photo stats
-router.get('/:slug/stats', verifyGalleryAccess, async (req, res) => {
+router.get('/:slug/stats', verifyGalleryAccess, blockHiddenGallery, async (req, res) => {
   try {
     const totalPhotos = await db('photos')
       .where('event_id', req.event.id)
diff --git a/backend/src/routes/galleryFeedback.js b/backend/src/routes/galleryFeedback.js
index f973b13a..c249a159 100644
--- a/backend/src/routes/galleryFeedback.js
+++ b/backend/src/routes/galleryFeedback.js
@@ -1,6 +1,7 @@
 const express = require('express');
 const router = express.Router();
 const { verifyGalleryAccess, denySlideshowToken } = require('../middleware/gallery');
+const { guestBlockedByReveal, blockHiddenGallery } = require('../utils/revealMode');
 const { feedbackRateLimit, generateGuestIdentifier } = require('../middleware/feedbackRateLimit');
 const { resolveGuest } = require('../middleware/guestAuth');
 const feedbackService = require('../services/feedbackService');
@@ -53,6 +54,9 @@ router.get('/:slug/feedback-settings',
 // Get feedback for a specific photo
 router.get('/:slug/photos/:photoId/feedback',
   verifyGalleryAccess,
+  // Reveal-gated (#838): sequential photo ids would let hidden-gallery
+  // guests enumerate comments/stats.
+  blockHiddenGallery,
   resolveGuest,
   validatePhotoId,
   checkValidation,
@@ -156,6 +160,8 @@ router.get('/:slug/photos/:photoId/feedback',
 router.post('/:slug/photos/:photoId/feedback',
   verifyGalleryAccess,
   denySlideshowToken,
+  // Reveal-gated (#838): no interacting with photos you cannot see.
+  blockHiddenGallery,
   resolveGuest,
   validatePhotoId,
   validateFeedbackSubmission,
@@ -326,7 +332,13 @@ router.get('/:slug/feedback-summary',
   async (req, res) => {
     try {
       const event = req.event;
-      
+
+      // Reveal mode (#838): the summary lists top photos by filename —
+      // hidden along with the gallery for plain guests.
+      if (guestBlockedByReveal(req)) {
+        return res.json({ enabled: false, summary: null });
+      }
+
       // Get feedback settings
       const settings = await feedbackService.getEventFeedbackSettings(event.id);
       
@@ -379,6 +391,13 @@ router.get('/:slug/my-feedback',
     try {
       const event = req.event;
 
+      // Reveal mode (#838): rows join photos (filename + storage path) —
+      // return the empty back-compat shape rather than a 403 so the gallery
+      // shell loading in parallel doesn't surface error toasts.
+      if (guestBlockedByReveal(req)) {
+        return res.json([]);
+      }
+
       const query = db('photo_feedback')
         .join('photos', 'photo_feedback.photo_id', 'photos.id')
         .where('photo_feedback.event_id', event.id);
diff --git a/backend/src/routes/protectedImages.js b/backend/src/routes/protectedImages.js
index 0bf9e725..2069920a 100644
--- a/backend/src/routes/protectedImages.js
+++ b/backend/src/routes/protectedImages.js
@@ -2,6 +2,7 @@ const express = require('express');
 const { db } = require('../database/db');
 const { formatBoolean } = require('../utils/dbCompat');
 const { verifyGalleryAccess } = require('../middleware/gallery');
+const { blockHiddenGallery, bypassesReveal, isGalleryHidden } = require('../utils/revealMode');
 const watermarkService = require('../services/watermarkService');
 const secureImageService = require('../services/secureImageService');
 const { getStorage } = require('../services/storage');
@@ -16,10 +17,13 @@ const router = express.Router();
 /**
  * Generate a signed URL token for image access
  */
-function generateImageToken(photoId, expiresIn = 3600) {
+function generateImageToken(photoId, expiresIn = 3600, revealBypass = false) {
   const secret = process.env.JWT_SECRET;
   const expires = Date.now() + (expiresIn * 1000);
-  const data = `${photoId}:${expires}`;
+  // Third segment (#838): whether the minting context bypasses reveal mode
+  // (slideshow/client/admin). Old two-segment tokens verify unchanged and
+  // read as no-bypass.
+  const data = `${photoId}:${expires}:${revealBypass ? 1 : 0}`;
   const signature = crypto.createHmac('sha256', secret).update(data).digest('hex');
   return `${Buffer.from(data).toString('base64')}.${signature}`;
 }
@@ -32,7 +36,7 @@ function verifyImageToken(token) {
     const secret = process.env.JWT_SECRET;
     const [data, signature] = token.split('.');
     const decoded = Buffer.from(data, 'base64').toString();
-    const [photoId, expires] = decoded.split(':');
+    const [photoId, expires, bypassFlag] = decoded.split(':');
     
     // Verify signature (constant-time — avoids leaking the HMAC byte-by-byte)
     const expectedSignature = crypto.createHmac('sha256', secret).update(decoded).digest('hex');
@@ -45,7 +49,7 @@ function verifyImageToken(token) {
       return null;
     }
     
-    return { photoId: parseInt(photoId), expires: parseInt(expires) };
+    return { photoId: parseInt(photoId), expires: parseInt(expires), revealBypass: bypassFlag === '1' };
   } catch (error) {
     return null;
   }
@@ -54,7 +58,7 @@ function verifyImageToken(token) {
 /**
  * Serve protected image with enhanced security
  */
-router.get('/:slug/photo/:photoId/view', verifyGalleryAccess, async (req, res) => {
+router.get('/:slug/photo/:photoId/view', verifyGalleryAccess, blockHiddenGallery, async (req, res) => {
   try {
     const { photoId } = req.params;
     const { protectionLevel = 'standard', token } = req.query;
@@ -174,7 +178,7 @@ router.get('/:slug/photo/:photoId/view', verifyGalleryAccess, async (req, res) =
 /**
  * Generate secure token for enhanced image access
  */
-router.post('/:slug/photo/:photoId/generate-secure-token', verifyGalleryAccess, async (req, res) => {
+router.post('/:slug/photo/:photoId/generate-secure-token', verifyGalleryAccess, blockHiddenGallery, async (req, res) => {
   try {
     const { photoId } = req.params;
     const { protectionLevel = 'standard', expiresIn = 300 } = req.body;
@@ -219,6 +223,11 @@ router.post('/:slug/photo/:photoId/generate-secure-token', verifyGalleryAccess,
  * Generate signed URL for image access (legacy support)
  */
 router.post('/:slug/photo/:photoId/generate-url', verifyGalleryAccess, async (req, res) => {
+  // Reveal-gated for plain guests; bypass callers get a token that stays
+  // valid at SERVE time too (third token segment below).
+  if (require('../utils/revealMode').guestBlockedByReveal(req)) {
+    return res.status(403).json({ error: 'Gallery is hidden until reveal', code: 'GALLERY_HIDDEN' });
+  }
   try {
     const { photoId } = req.params;
     
@@ -235,7 +244,7 @@ router.post('/:slug/photo/:photoId/generate-url', verifyGalleryAccess, async (re
     }
     
     // Generate signed token
-    const token = generateImageToken(photoId);
+    const token = generateImageToken(photoId, 3600, bypassesReveal(req));
     const signedUrl = `/api/images/${req.params.slug}/photo/${photoId}/signed/${token}`;
     
     res.json({ 
@@ -271,7 +280,13 @@ router.get('/:slug/photo/:photoId/signed/:token', async (req, res) => {
     if (!event) {
       return res.status(404).json({ error: 'Event not found' });
     }
-    
+
+    // Reveal mode (#838): a signed URL minted before a re-hide must not keep
+    // serving hidden photos; tokens minted by bypass contexts carry the flag.
+    if (isGalleryHidden(event) && !tokenData.revealBypass) {
+      return res.status(403).json({ error: 'Gallery is hidden until reveal', code: 'GALLERY_HIDDEN' });
+    }
+
     // Get photo
     const photo = await db('photos')
       .where({
diff --git a/backend/src/routes/secureImages.js b/backend/src/routes/secureImages.js
index fcd7c065..2dda8c0a 100644
--- a/backend/src/routes/secureImages.js
+++ b/backend/src/routes/secureImages.js
@@ -1,6 +1,7 @@
 const express = require('express');
 const { db } = require('../database/db');
 const { verifyGalleryAccess, denySlideshowToken } = require('../middleware/gallery');
+const { blockHiddenGallery, bypassesReveal, isGalleryHidden } = require('../utils/revealMode');
 const secureImageService = require('../services/secureImageService');
 const secureImageMiddleware = require('../middleware/secureImageMiddleware');
 const logger = require('../utils/logger');
@@ -23,7 +24,7 @@ router.post('/:slug/generate-token', async (req, res, next) => {
   // Add slug to request for verifyGalleryAccess
   req.requestedSlug = req.params.slug;
   next();
-}, verifyGalleryAccess, denySlideshowToken, async (req, res) => {
+}, verifyGalleryAccess, denySlideshowToken, blockHiddenGallery, async (req, res) => {
   try {
     const { photoId, accessType = 'view' } = req.body;
     
@@ -51,7 +52,10 @@ router.post('/:slug/generate-token', async (req, res, next) => {
       expiresIn: protectionLevel === 'maximum' ? 180 : 300, // 3-5 minutes
       maxUses: accessType === 'download' ? 1 : 3,
       clientFingerprint,
-      protectionLevel
+      protectionLevel,
+      // Reveal mode (#838): recorded in the token so a re-hide invalidates
+      // in-flight guest tokens at serve time without breaking the slideshow.
+      revealBypass: bypassesReveal(req)
     };
 
     const token = secureImageService.generateSecureToken(
@@ -137,6 +141,12 @@ router.get('/:slug/secure/:photoId/:token',
         return res.status(404).json({ error: 'Gallery not found' });
       }
 
+      // Reveal mode (#838): tokens minted by plain guests die the moment the
+      // gallery is (re-)hidden — bypass contexts keep working.
+      if (isGalleryHidden(event) && !tokenValidation.data?.revealBypass) {
+        return res.status(403).json({ error: 'Gallery is hidden until reveal', code: 'GALLERY_HIDDEN' });
+      }
+
       // Verify photo exists and belongs to event  
       const photo = await db('photos')
         .where({ id: photoId, event_id: event.id })
@@ -273,6 +283,7 @@ router.get('/:slug/secure-download/:photoId/:token',
     next();
   },
   verifyGalleryAccess,
+  blockHiddenGallery,
   denySlideshowToken,
   async (req, res) => {
     try {
diff --git a/backend/src/services/galleryOgService.js b/backend/src/services/galleryOgService.js
index 5cac9cf6..141a528d 100644
--- a/backend/src/services/galleryOgService.js
+++ b/backend/src/services/galleryOgService.js
@@ -207,7 +207,11 @@ async function buildOgMetadata(slug, requestPath) {
   // the logo on any of those misses so a half-configured event still
   // gets a polished link preview rather than a broken image.
   let image = logoUrl;
-  if (event.og_image_share_enabled && event.hero_photo_id) {
+  // Reveal mode (#838): while the gallery is hidden from guests, social
+  // crawlers must not get the hero photo either — fall back to the brand
+  // logo like the opt-out case.
+  const { isGalleryHidden } = require('../utils/revealMode');
+  if (event.og_image_share_enabled && event.hero_photo_id && !isGalleryHidden(event)) {
     const heroPhoto = await db('photos')
       .where({ id: event.hero_photo_id, event_id: event.id })
       .select('id', 'thumbnail_path')
@@ -302,7 +306,8 @@ async function handleGalleryOgCover(req, res) {
       return;
     }
     const event = await resolveSlug(slug);
-    if (!event || !event.og_image_share_enabled || !event.hero_photo_id) {
+    const { isGalleryHidden } = require('../utils/revealMode');
+    if (!event || !event.og_image_share_enabled || !event.hero_photo_id || isGalleryHidden(event)) {
       res.status(404).type('text/plain').send('Cover not available');
       return;
     }
diff --git a/backend/src/services/revealScheduler.js b/backend/src/services/revealScheduler.js
new file mode 100644
index 00000000..a1458c2e
--- /dev/null
+++ b/backend/src/services/revealScheduler.js
@@ -0,0 +1,76 @@
+/**
+ * Reveal scheduler (#838). Runs every minute (the expiration checker's
+ * hourly cadence is too coarse for a party reveal) and stamps revealed_at on
+ * events whose scheduled reveal_at has passed.
+ *
+ * The stamp is bookkeeping, not the gate: the gallery routes compute
+ * effective visibility from reveal_at at request time, so the reveal happens
+ * exactly on schedule even if this job lags. The scheduler makes the state
+ * durable, writes the activity log entry, and emits the `gallery.revealed`
+ * workflow trigger so hosts can hook a notification email onto it.
+ */
+
+const cron = require('node-cron');
+const { db, logActivity } = require('../database/db');
+const { formatBoolean } = require('../utils/dbCompat');
+const logger = require('../utils/logger');
+
+async function checkScheduledReveals() {
+  try {
+    const now = new Date().toISOString();
+    const due = await db('events')
+      .where('reveal_mode', formatBoolean(true))
+      .whereNull('revealed_at')
+      .whereNotNull('reveal_at')
+      .where('reveal_at', '<=', now)
+      .where('is_active', formatBoolean(true))
+      .where('is_archived', formatBoolean(false))
+      // Drafts aren't guest-reachable — stamping/notifying would burn the
+      // reveal before publication and fire workflows for a dead link.
+      .where('is_draft', formatBoolean(false));
+
+    for (const event of due) {
+      // Conditional update: another worker (multi-replica) may have stamped
+      // it between the select and here — exactly one emits the events.
+      // Consume the schedule like "Reveal now" does — a stale past
+      // reveal_at would otherwise instantly re-open the gate when the
+      // gallery is later re-armed without a fresh schedule.
+      const stamped = await db('events')
+        .where('id', event.id)
+        .whereNull('revealed_at')
+        .update({ revealed_at: event.reveal_at, reveal_at: null });
+      if (stamped !== 1) continue;
+
+      logger.info('Reveal mode: scheduled reveal fired', { eventId: event.id, slug: event.slug });
+      await logActivity('gallery_revealed', { scheduled: true, reveal_at: event.reveal_at }, event.id);
+
+      // Best-effort trigger for custom notification flows — never throws
+      // into the scheduler and no-ops when nothing subscribes.
+      try {
+        await require('./workflows').emitWorkflowEvent('gallery.revealed', {
+          entityType: 'event',
+          entityId: event.id,
+          dedupSuffix: String(new Date(event.reveal_at).getTime()),
+          payload: {
+            eventId: event.id,
+            slug: event.slug,
+            eventName: event.event_name,
+            revealedAt: event.reveal_at,
+            scheduled: true,
+          },
+        });
+      } catch (err) {
+        logger.warn('Failed to emit gallery.revealed workflow event', { eventId: event.id, error: err.message });
+      }
+    }
+  } catch (error) {
+    logger.error('Reveal scheduler pass failed:', error);
+  }
+}
+
+function startRevealScheduler() {
+  cron.schedule('* * * * *', checkScheduledReveals);
+  logger.info('Reveal scheduler started');
+}
+
+module.exports = { startRevealScheduler, checkScheduledReveals };
diff --git a/backend/src/services/secureImageService.js b/backend/src/services/secureImageService.js
index fc2e9551..4e7a7ae9 100644
--- a/backend/src/services/secureImageService.js
+++ b/backend/src/services/secureImageService.js
@@ -21,7 +21,11 @@ class SecureImageService {
       expiresIn = 300, // 5 minutes default
       maxUses = 1,
       clientFingerprint = '',
-      protectionLevel = 'standard'
+      protectionLevel = 'standard',
+      // Reveal mode (#838): whether the minting context bypasses the
+      // hidden-gallery gate — re-checked at SERVE time so a re-hide
+      // invalidates in-flight guest tokens without breaking the slideshow.
+      revealBypass = false
     } = options;
 
     const tokenData = {
@@ -32,6 +36,7 @@ class SecureImageService {
       maxUses,
       usedCount: 0,
       protectionLevel,
+      revealBypass,
       createdAt: Date.now()
     };
 
diff --git a/backend/src/services/workflows/engine.js b/backend/src/services/workflows/engine.js
index d1766a1a..8bfccb87 100644
--- a/backend/src/services/workflows/engine.js
+++ b/backend/src/services/workflows/engine.js
@@ -263,7 +263,7 @@ async function resumeRun(runId, { decisionHandle = null } = {}) {
  * workflow (idempotent via dedup_key) and starts it. Never throws — safe to
  * call after a caller's commit. Fails CLOSED if the flag system is unavailable.
  */
-async function emitWorkflowEvent(triggerType, { entityType = null, entityId = null, payload = {}, targetWorkflowId = null } = {}) {
+async function emitWorkflowEvent(triggerType, { entityType = null, entityId = null, payload = {}, targetWorkflowId = null, dedupSuffix = null } = {}) {
   try {
     const { isFeatureEnabled } = require('../../middleware/requireFeatureFlag');
     let enabled = false;
@@ -285,7 +285,10 @@ async function emitWorkflowEvent(triggerType, { entityType = null, entityId = nu
       const tcfg = parseJson(wf.trigger_config, {});
       if (tcfg && tcfg.filter && !matchFilter(tcfg.filter, payload)) continue;
 
-      const dedupKey = `${wf.id}:${wf.version}:${triggerType}:${entityType || ''}:${entityId || ''}`;
+      // dedupSuffix (#838): repeatable lifecycle events (a gallery can be
+      // re-hidden and revealed again) append a cycle marker so each cycle
+      // gets its own run while accidental double-emits still dedupe.
+      const dedupKey = `${wf.id}:${wf.version}:${triggerType}:${entityType || ''}:${entityId || ''}${dedupSuffix ? `:${dedupSuffix}` : ''}`;
       const existing = await db('workflow_runs').where({ dedup_key: dedupKey }).first();
       if (existing) continue;
 
diff --git a/backend/src/utils/revealMode.js b/backend/src/utils/revealMode.js
new file mode 100644
index 00000000..d10e074d
--- /dev/null
+++ b/backend/src/utils/revealMode.js
@@ -0,0 +1,75 @@
+/**
+ * Reveal mode (#838): effective-visibility math, shared by the gallery
+ * routes, the admin routes and the reveal scheduler.
+ *
+ * The gate is computed from the event row at request time — a scheduled
+ * reveal opens EXACTLY at reveal_at even if the minutely scheduler (which
+ * only stamps revealed_at durably and fires notifications) lags behind.
+ */
+
+/** Truthy check that survives SQLite 0/1 and Postgres booleans. */
+function isTrue(value) {
+  return value === true || value === 1 || value === '1';
+}
+
+/**
+ * Parse a timestamp column that may arrive as a Date (Postgres), an ISO
+ * string, or a millisecond number/number-string (SQLite stores knex Dates
+ * as ms — `new Date("178…")` on that string would be Invalid Date and
+ * silently keep the gallery hidden past its scheduled reveal).
+ */
+function toDate(value) {
+  if (value instanceof Date) return value;
+  if (typeof value === 'number') return new Date(value);
+  const asNumber = Number(value);
+  if (!Number.isNaN(asNumber) && String(value).trim() !== '') return new Date(asNumber);
+  return new Date(value);
+}
+
+/**
+ * Whether the gallery is currently hidden from plain guests.
+ * Host/admin/slideshow/client access bypasses this at the route layer.
+ */
+function isGalleryHidden(event, now = new Date()) {
+  if (!isTrue(event.reveal_mode)) return false;
+  if (event.revealed_at) return false;
+  if (event.reveal_at && toDate(event.reveal_at) <= now) return false;
+  return true;
+}
+
+/**
+ * Which access levels see the full gallery while it is hidden:
+ * the live slideshow (the "surprise beamer" case), client access and
+ * customer-portal-minted tokens (both are the host/customer reviewing
+ * their own event — those tokens carry via:'customer' with NO accessLevel,
+ * so accessLevel alone would misclassify them as guests) and the admin
+ * preview.
+ */
+function bypassesReveal(req) {
+  if (req.accessLevel === 'slideshow' || req.accessLevel === 'client') return true;
+  if (req.viaCustomer) return true;
+  // Lazy require avoids a cycle: middleware/gallery requires nothing from
+  // here, but keeping the import local makes that permanent.
+  const { isAdminPreview } = require('../middleware/gallery');
+  return Boolean(isAdminPreview(req));
+}
+
+/** Route guard result: is THIS request blocked by reveal mode? */
+function guestBlockedByReveal(req, now = new Date()) {
+  return isGalleryHidden(req.event, now) && !bypassesReveal(req);
+}
+
+/**
+ * Route guard: hard 403 for plain guests on photo/derivative/download
+ * endpoints while the gallery is hidden. Photo IDs are sequential, so
+ * gating only the listing would leave images probeable. Mount AFTER
+ * verifyGalleryAccess (needs req.event / req.accessLevel).
+ */
+function blockHiddenGallery(req, res, next) {
+  if (guestBlockedByReveal(req)) {
+    return res.status(403).json({ error: 'Gallery is hidden until reveal', code: 'GALLERY_HIDDEN' });
+  }
+  next();
+}
+
+module.exports = { isGalleryHidden, bypassesReveal, guestBlockedByReveal, blockHiddenGallery };
diff --git a/frontend/src/components/gallery/GalleryView.tsx b/frontend/src/components/gallery/GalleryView.tsx
index aa4a8d51..e50d62b2 100644
--- a/frontend/src/components/gallery/GalleryView.tsx
+++ b/frontend/src/components/gallery/GalleryView.tsx
@@ -140,6 +140,24 @@ export const GalleryView: React.FC<GalleryViewProps> = ({ slug, event }) => {
     }
   }, [data?.event?.default_photo_sort, defaultSortApplied]);
 
+  // Reveal mode (#838): an already-open view must follow reveal-state
+  // changes in BOTH directions — hidden→visible at reveal_at (or manual
+  // "Reveal now"), and visible→hidden on a re-hide. Refetch right at
+  // reveal_at plus a 60s poll while the mode is armed; there is no push
+  // channel.
+  const hiddenUntilReveal = data?.hidden_until_reveal === true;
+  const revealArmed = (data?.event as { reveal_armed?: boolean } | undefined)?.reveal_armed === true;
+  const revealAtMs = data?.reveal_at ? new Date(data.reveal_at).getTime() : null;
+  useEffect(() => {
+    if (!hiddenUntilReveal && !revealArmed) return undefined;
+    const timers: Array<ReturnType<typeof setTimeout>> = [];
+    if (revealAtMs && revealAtMs > Date.now()) {
+      timers.push(setTimeout(() => { refetch(); }, Math.min(revealAtMs - Date.now() + 1000, 2 ** 31 - 1)));
+    }
+    const interval = setInterval(() => { refetch(); }, 60_000);
+    return () => { timers.forEach(clearTimeout); clearInterval(interval); };
+  }, [hiddenUntilReveal, revealArmed, revealAtMs, refetch]);
+
   // Get individual protection settings from event
   const disableRightClick = data?.event?.disable_right_click === true;
   const enableDevtoolsProtection = data?.event?.enable_devtools_protection === true;
@@ -701,6 +719,58 @@ export const GalleryView: React.FC<GalleryViewProps> = ({ slug, event }) => {
     && settingsData?.gallery_show_filter_bar !== false
     && (data?.photos?.length ?? 0) > 0;
 
+  // Reveal mode (#838): the server returned the event shell with no photos —
+  // render the upload-only view for EVERY layout. Enforcement is server-side
+  // (the photo endpoints refuse plain guests); this is the friendly face.
+  if (hiddenUntilReveal) {
+    const uploadsOn = Boolean(data?.event?.allow_user_uploads || event?.allow_user_uploads);
+    return (
+      <GalleryLayout event={event} brandingSettings={brandingSettings}>
+        <div className="max-w-xl mx-auto text-center py-16 px-4">
+          <div className="mx-auto mb-5 w-16 h-16 rounded-full bg-surface flex items-center justify-center">
+            <EyeOff className="w-8 h-8 text-muted-theme" />
+          </div>
+          <h2 className="text-2xl font-semibold mb-3" style={{ color: 'var(--color-text, #171717)' }}>
+            {t('gallery.revealPendingTitle', 'The photos are still a surprise')}
+          </h2>
+          <p className="text-muted-theme mb-2">
+            {t('gallery.revealPendingMessage', 'The host will reveal the gallery later — check back soon!')}
+          </p>
+          {data.reveal_at && (
+            <p className="text-sm text-muted-theme mb-6">
+              {t('gallery.revealScheduledFor', 'Reveal scheduled for {{date}}', {
+                date: new Date(data.reveal_at).toLocaleString(),
+              })}
+            </p>
+          )}
+          {uploadsOn && (
+            <div className="mt-6">
+              <p className="text-sm text-muted-theme mb-3">
+                {t('gallery.revealUploadHint', 'You can already add your own photos to the collection:')}
+              </p>
+              <Button
+                variant="primary"
+                size="lg"
+                leftIcon={<Upload className="w-5 h-5" />}
+                onClick={() => setShowUploadModal(true)}
+              >
+                {t('upload.uploadPhotos', 'Upload Photos')}
+              </Button>
+            </div>
+          )}
+        </div>
+        {showUploadModal && uploadsOn && (
+          <UserPhotoUpload
+            eventId={data?.event?.id || event?.id}
+            categoryId={data?.event?.upload_category_id || event?.upload_category_id}
+            onUploadComplete={() => setShowUploadModal(false)}
+            onClose={() => setShowUploadModal(false)}
+          />
+        )}
+      </GalleryLayout>
+    );
+  }
+
   // Full-page layouts (gallery-premium, gallery-story) have their own integrated UI
   // Skip all wrapper elements (header, footer, sidebar, filters) for these layouts
   const isFullPageLayout = theme.galleryLayout === 'gallery-premium' || theme.galleryLayout === 'gallery-story';
diff --git a/frontend/src/i18n/locales/de.json b/frontend/src/i18n/locales/de.json
index b62ee3d6..36657ce1 100644
--- a/frontend/src/i18n/locales/de.json
+++ b/frontend/src/i18n/locales/de.json
@@ -813,6 +813,10 @@
     }
   },
   "gallery": {
+    "revealPendingTitle": "Die Fotos sind noch eine Überraschung",
+    "revealPendingMessage": "Der Gastgeber gibt die Galerie später frei — schauen Sie bald wieder vorbei!",
+    "revealScheduledFor": "Freigabe geplant für {{date}}",
+    "revealUploadHint": "Sie können schon jetzt eigene Fotos zur Sammlung beitragen:",
     "expires": "Läuft ab",
     "expired": "Abgelaufen",
     "contactOrganizer": "Bitte kontaktieren Sie den Veranstalter, wenn Sie Zugriff auf diese Fotos benötigen.",
@@ -964,6 +968,17 @@
     "failedToToggleDownloads": "Aktualisierung der Download-Berechtigung fehlgeschlagen"
   },
   "events": {
+    "revealMode": "Reveal-Modus (Galerie bis zur Freigabe verbergen)",
+    "revealModeHelp": "Gäste können hochladen, sehen aber keine Fotos, bis Sie die Galerie freigeben — manuell oder zum geplanten Zeitpunkt. Diashow und Kundenzugang funktionieren weiter.",
+    "revealAt": "Geplante Freigabe (optional)",
+    "revealAtHelp": "Leer lassen, um manuell mit „Jetzt freigeben\" freizugeben.",
+    "revealModeStatus": "Reveal-Modus",
+    "revealed": "Freigegeben",
+    "hiddenUntilReveal": "Für Gäste verborgen",
+    "revealScheduled": "Geplant: {{date}}",
+    "revealNow": "Jetzt freigeben",
+    "revealedToast": "Galerie freigegeben — Gäste sehen die Fotos jetzt",
+    "revealError": "Galerie konnte nicht freigegeben werden",
     "totalPhotos": "Gesamtfotos",
     "totalViews": "Gesamtaufrufe",
     "totalDownloads": "Gesamte Downloads",
diff --git a/frontend/src/i18n/locales/en.json b/frontend/src/i18n/locales/en.json
index 6f9d1b1c..a753c5f3 100644
--- a/frontend/src/i18n/locales/en.json
+++ b/frontend/src/i18n/locales/en.json
@@ -360,6 +360,10 @@
     }
   },
   "gallery": {
+    "revealPendingTitle": "The photos are still a surprise",
+    "revealPendingMessage": "The host will reveal the gallery later — check back soon!",
+    "revealScheduledFor": "Reveal scheduled for {{date}}",
+    "revealUploadHint": "You can already add your own photos to the collection:",
     "expires": "Expires",
     "expired": "Expired",
     "contactOrganizer": "Please contact the event organizer if you need access to these photos.",
@@ -511,6 +515,17 @@
     "failedToToggleDownloads": "Failed to update download permission"
   },
   "events": {
+    "revealMode": "Reveal mode (hide gallery until reveal)",
+    "revealModeHelp": "Guests can upload but see no photos until you reveal the gallery — manually or at the scheduled time. Slideshow and client access keep working.",
+    "revealAt": "Scheduled reveal (optional)",
+    "revealAtHelp": "Leave empty to reveal manually with the \"Reveal now\" button.",
+    "revealModeStatus": "Reveal mode",
+    "revealed": "Revealed",
+    "hiddenUntilReveal": "Hidden from guests",
+    "revealScheduled": "Scheduled: {{date}}",
+    "revealNow": "Reveal now",
+    "revealedToast": "Gallery revealed — guests can see the photos now",
+    "revealError": "Failed to reveal the gallery",
     "title": "Events",
     "create": "Create",
     "createEvent": "Create Event",
diff --git a/frontend/src/i18n/locales/es.json b/frontend/src/i18n/locales/es.json
index c29f0479..e4a48a8b 100644
--- a/frontend/src/i18n/locales/es.json
+++ b/frontend/src/i18n/locales/es.json
@@ -223,6 +223,10 @@
     "passwordHint": "La contraseña la proporcionó el organizador del evento. Contacta con ellos si no la tienes."
   },
   "gallery": {
+    "revealPendingTitle": "Las fotos siguen siendo una sorpresa",
+    "revealPendingMessage": "El anfitrión revelará la galería más tarde — ¡vuelve pronto!",
+    "revealScheduledFor": "Revelación programada para {{date}}",
+    "revealUploadHint": "Ya puedes añadir tus propias fotos a la colección:",
     "title": "Galería de fotos",
     "welcomeMessage": "Mensaje de bienvenida",
     "expiresOn": "Expira el",
@@ -342,6 +346,17 @@
     "categoryHeroHint": "Si no se establece una foto de portada para una categoría, se usará la foto hero por defecto."
   },
   "events": {
+    "revealMode": "Modo revelación (ocultar la galería hasta revelarla)",
+    "revealModeHelp": "Los invitados pueden subir fotos pero no verlas hasta que reveles la galería — manualmente o a la hora programada. La presentación y el acceso de clientes siguen funcionando.",
+    "revealAt": "Revelación programada (opcional)",
+    "revealAtHelp": "Déjalo vacío para revelar manualmente con el botón \"Revelar ahora\".",
+    "revealModeStatus": "Modo revelación",
+    "revealed": "Revelada",
+    "hiddenUntilReveal": "Oculta para los invitados",
+    "revealScheduled": "Programada: {{date}}",
+    "revealNow": "Revelar ahora",
+    "revealedToast": "Galería revelada — los invitados ya pueden ver las fotos",
+    "revealError": "No se pudo revelar la galería",
     "title": "Eventos",
     "create": "Crear",
     "createEvent": "Crear evento",
diff --git a/frontend/src/i18n/locales/fr.json b/frontend/src/i18n/locales/fr.json
index 28720ba1..1b30f209 100644
--- a/frontend/src/i18n/locales/fr.json
+++ b/frontend/src/i18n/locales/fr.json
@@ -221,6 +221,10 @@
     "passwordHint": "Le mot de passe a été fourni par l'organisateur de l'événement. Contactez-le si vous ne l'avez pas."
   },
   "gallery": {
+    "revealPendingTitle": "Les photos sont encore une surprise",
+    "revealPendingMessage": "L'hôte dévoilera la galerie plus tard — revenez bientôt !",
+    "revealScheduledFor": "Révélation prévue le {{date}}",
+    "revealUploadHint": "Vous pouvez déjà ajouter vos propres photos à la collection :",
     "expires": "Expire",
     "expired": "Expiré",
     "contactOrganizer": "Veuillez contacter l'organisateur de l'événement si vous avez besoin d'accéder à ces photos.",
@@ -358,6 +362,17 @@
     "categoryHeroHint": "Si aucune photo de couverture n'est définie pour une catégorie, la photo par défaut sera utilisée."
   },
   "events": {
+    "revealMode": "Mode révélation (masquer la galerie jusqu'à la révélation)",
+    "revealModeHelp": "Les invités peuvent téléverser mais ne voient aucune photo tant que vous ne révélez pas la galerie — manuellement ou à l'heure programmée. Le diaporama et l'accès client continuent de fonctionner.",
+    "revealAt": "Révélation programmée (optionnel)",
+    "revealAtHelp": "Laissez vide pour révéler manuellement avec le bouton « Révéler maintenant ».",
+    "revealModeStatus": "Mode révélation",
+    "revealed": "Révélée",
+    "hiddenUntilReveal": "Masquée pour les invités",
+    "revealScheduled": "Programmée : {{date}}",
+    "revealNow": "Révéler maintenant",
+    "revealedToast": "Galerie révélée — les invités peuvent maintenant voir les photos",
+    "revealError": "Impossible de révéler la galerie",
     "title": "Événements",
     "create": "Créer",
     "createEvent": "Créer un événement",
diff --git a/frontend/src/i18n/locales/nl.json b/frontend/src/i18n/locales/nl.json
index 94f871d1..77da18b9 100644
--- a/frontend/src/i18n/locales/nl.json
+++ b/frontend/src/i18n/locales/nl.json
@@ -221,6 +221,10 @@
     "passwordHint": "Het wachtwoord is verstrekt door de organisator van het evenement. Neem contact op als u het niet heeft."
   },
   "gallery": {
+    "revealPendingTitle": "De foto's zijn nog een verrassing",
+    "revealPendingMessage": "De gastheer onthult de galerij later — kom snel terug!",
+    "revealScheduledFor": "Onthulling gepland voor {{date}}",
+    "revealUploadHint": "Je kunt nu al je eigen foto's aan de collectie toevoegen:",
     "expires": "Verloopt",
     "expired": "Verlopen",
     "contactOrganizer": "Neem contact op met de organisator als u toegang tot deze foto's nodig heeft.",
@@ -358,6 +362,17 @@
     "categoryHeroHint": "Als er geen omslagfoto is ingesteld voor een categorie, wordt de standaard hero-foto gebruikt."
   },
   "events": {
+    "revealMode": "Onthullingsmodus (galerij verbergen tot de onthulling)",
+    "revealModeHelp": "Gasten kunnen uploaden maar zien geen foto's totdat je de galerij onthult — handmatig of op het geplande tijdstip. Diavoorstelling en klanttoegang blijven werken.",
+    "revealAt": "Geplande onthulling (optioneel)",
+    "revealAtHelp": "Laat leeg om handmatig te onthullen met de knop \"Nu onthullen\".",
+    "revealModeStatus": "Onthullingsmodus",
+    "revealed": "Onthuld",
+    "hiddenUntilReveal": "Verborgen voor gasten",
+    "revealScheduled": "Gepland: {{date}}",
+    "revealNow": "Nu onthullen",
+    "revealedToast": "Galerij onthuld — gasten kunnen de foto's nu zien",
+    "revealError": "Galerij onthullen mislukt",
     "title": "Evenementen",
     "create": "Aanmaken",
     "createEvent": "Evenement aanmaken",
diff --git a/frontend/src/i18n/locales/pt.json b/frontend/src/i18n/locales/pt.json
index 588647a8..85aeed57 100644
--- a/frontend/src/i18n/locales/pt.json
+++ b/frontend/src/i18n/locales/pt.json
@@ -224,6 +224,10 @@
     "passwordHint": "A senha foi fornecida pelo organizador do evento. Entre em contato se não a tiver."
   },
   "gallery": {
+    "revealPendingTitle": "As fotos ainda são uma surpresa",
+    "revealPendingMessage": "O anfitrião revelará a galeria mais tarde — volte em breve!",
+    "revealScheduledFor": "Revelação agendada para {{date}}",
+    "revealUploadHint": "Você já pode adicionar suas próprias fotos à coleção:",
     "expires": "Expira",
     "expired": "Expirada",
     "contactOrganizer": "Entre em contato com o organizador do evento se precisar de acesso a estas fotos",
@@ -366,6 +370,17 @@
     "categoryHeroHint": "Se nenhuma foto de capa for definida, a foto de destaque padrão será usada."
   },
   "events": {
+    "revealMode": "Modo revelação (ocultar a galeria até a revelação)",
+    "revealModeHelp": "Os convidados podem enviar fotos, mas não as veem até você revelar a galeria — manualmente ou no horário agendado. A apresentação de slides e o acesso do cliente continuam funcionando.",
+    "revealAt": "Revelação agendada (opcional)",
+    "revealAtHelp": "Deixe vazio para revelar manualmente com o botão \"Revelar agora\".",
+    "revealModeStatus": "Modo revelação",
+    "revealed": "Revelada",
+    "hiddenUntilReveal": "Oculta para os convidados",
+    "revealScheduled": "Agendada: {{date}}",
+    "revealNow": "Revelar agora",
+    "revealedToast": "Galeria revelada — os convidados já podem ver as fotos",
+    "revealError": "Falha ao revelar a galeria",
     "title": "Eventos",
     "create": "Criar",
     "createEvent": "Criar Evento",
diff --git a/frontend/src/i18n/locales/ru.json b/frontend/src/i18n/locales/ru.json
index d9c68c6f..92459cd3 100644
--- a/frontend/src/i18n/locales/ru.json
+++ b/frontend/src/i18n/locales/ru.json
@@ -227,6 +227,10 @@
     "passwordHint": "Пароль предоставлен организатором события. Свяжитесь с ним, если у вас его нет."
   },
   "gallery": {
+    "revealPendingTitle": "Фотографии пока остаются сюрпризом",
+    "revealPendingMessage": "Организатор откроет галерею позже — загляните ещё раз!",
+    "revealScheduledFor": "Открытие запланировано на {{date}}",
+    "revealUploadHint": "Вы уже можете добавить свои фотографии в коллекцию:",
     "expires": "Истекает",
     "expired": "Истекла",
     "contactOrganizer": "Свяжитесь с организатором события, если вам нужен доступ к этим фотографиям",
@@ -374,6 +378,17 @@
     "categoryHeroHint": "Если обложка для категории не задана, будет использоваться стандартное главное фото."
   },
   "events": {
+    "revealMode": "Режим сюрприза (скрыть галерею до открытия)",
+    "revealModeHelp": "Гости могут загружать фото, но не видят их, пока вы не откроете галерею — вручную или в запланированное время. Слайд-шоу и клиентский доступ продолжают работать.",
+    "revealAt": "Запланированное открытие (необязательно)",
+    "revealAtHelp": "Оставьте пустым, чтобы открыть вручную кнопкой «Открыть сейчас».",
+    "revealModeStatus": "Режим сюрприза",
+    "revealed": "Открыта",
+    "hiddenUntilReveal": "Скрыта от гостей",
+    "revealScheduled": "Запланировано: {{date}}",
+    "revealNow": "Открыть сейчас",
+    "revealedToast": "Галерея открыта — гости теперь видят фотографии",
+    "revealError": "Не удалось открыть галерею",
     "title": "События",
     "create": "Создать",
     "createEvent": "Создать событие",
diff --git a/frontend/src/i18n/locales/sl.json b/frontend/src/i18n/locales/sl.json
index 066dab76..e5f8cde8 100644
--- a/frontend/src/i18n/locales/sl.json
+++ b/frontend/src/i18n/locales/sl.json
@@ -221,6 +221,10 @@
     "passwordHint": "Geslo vam je posredoval organizator dogodka. Če ga nimate, se obrnite nanj."
   },
   "gallery": {
+    "revealPendingTitle": "Fotografije so še presenečenje",
+    "revealPendingMessage": "Gostitelj bo galerijo razkril pozneje — kmalu preverite znova!",
+    "revealScheduledFor": "Razkritje načrtovano za {{date}}",
+    "revealUploadHint": "Svoje fotografije lahko dodate v zbirko že zdaj:",
     "expires": "Poteče",
     "expired": "Poteklo",
     "contactOrganizer": "Če potrebujete dostop do teh fotografij, se obrnite na organizatorja dogodka.",
@@ -358,6 +362,17 @@
     "categoryHeroHint": "Če za kategorijo ni nastavljena naslovna fotografija, bo uporabljena privzeta hero fotografija."
   },
   "events": {
+    "revealMode": "Način razkritja (skrij galerijo do razkritja)",
+    "revealModeHelp": "Gostje lahko nalagajo fotografije, vendar jih ne vidijo, dokler galerije ne razkrijete — ročno ali ob načrtovanem času. Diaprojekcija in dostop za stranke delujeta naprej.",
+    "revealAt": "Načrtovano razkritje (neobvezno)",
+    "revealAtHelp": "Pustite prazno za ročno razkritje z gumbom »Razkrij zdaj«.",
+    "revealModeStatus": "Način razkritja",
+    "revealed": "Razkrita",
+    "hiddenUntilReveal": "Skrita za goste",
+    "revealScheduled": "Načrtovano: {{date}}",
+    "revealNow": "Razkrij zdaj",
+    "revealedToast": "Galerija razkrita — gostje zdaj vidijo fotografije",
+    "revealError": "Galerije ni bilo mogoče razkriti",
     "title": "Dogodki",
     "create": "Ustvari",
     "createEvent": "Ustvari dogodek",
diff --git a/frontend/src/pages/admin/EventDetailsPage.tsx b/frontend/src/pages/admin/EventDetailsPage.tsx
index c661bbfe..80091dc8 100644
--- a/frontend/src/pages/admin/EventDetailsPage.tsx
+++ b/frontend/src/pages/admin/EventDetailsPage.tsx
@@ -206,6 +206,18 @@ export const EventDetailsPage: React.FC = () => {
   });
 
   // Archive mutation
+  // Reveal now (#838)
+  const revealMutation = useMutation({
+    mutationFn: () => eventsService.revealEvent(Number(id)),
+    onSuccess: () => {
+      toast.success(t('events.revealedToast', 'Gallery revealed — guests can see the photos now'));
+      refetchEvent();
+    },
+    onError: () => {
+      toast.error(t('events.revealError', 'Failed to reveal the gallery'));
+    },
+  });
+
   const archiveMutation = useMutation({
     mutationFn: () => eventsService.archiveEvent(parseInt(id!)),
     onSuccess: () => {
@@ -289,6 +301,11 @@ export const EventDetailsPage: React.FC = () => {
       css_template_id: event.css_template_id || null,
       expires_at: expiresAtDate ? format(expiresAtDate, 'yyyy-MM-dd') : '',
       allow_user_uploads: event.allow_user_uploads || false,
+      reveal_mode: event.reveal_mode || false,
+      // datetime-local wants local "YYYY-MM-DDTHH:mm"
+      reveal_at: event.reveal_at
+        ? (() => { const d = new Date(event.reveal_at); d.setMinutes(d.getMinutes() - d.getTimezoneOffset()); return d.toISOString().slice(0, 16); })()
+        : '',
       upload_category_id: event.upload_category_id || null,
       hero_photo_id: event.hero_photo_id || null,
       customer_name: event.customer_name || '',
@@ -428,6 +445,10 @@ export const EventDetailsPage: React.FC = () => {
     const updateData: any = {
       expires_at: editForm.expires_at || null,
       allow_user_uploads: editForm.allow_user_uploads,
+      reveal_mode: editForm.allow_user_uploads && editForm.reveal_mode,
+      reveal_at: editForm.allow_user_uploads && editForm.reveal_mode && editForm.reveal_at
+        ? new Date(editForm.reveal_at).toISOString()
+        : null,
       require_password: editForm.require_password,
       css_template_id: editForm.css_template_id,
       // Download protection settings
@@ -566,6 +587,7 @@ export const EventDetailsPage: React.FC = () => {
           photos={photos}
           phoneFieldEnabled={phoneFieldEnabled}
           daysUntilExpiration={daysUntilExpiration}
+          onRevealNow={() => revealMutation.mutate()}
           refetchEvent={refetchEvent}
           setActiveTab={setActiveTab}
           setShowPasswordReset={setShowPasswordReset}
diff --git a/frontend/src/pages/admin/event-details/EventInformationCard.tsx b/frontend/src/pages/admin/event-details/EventInformationCard.tsx
index 24290e85..8f7079c5 100644
--- a/frontend/src/pages/admin/event-details/EventInformationCard.tsx
+++ b/frontend/src/pages/admin/event-details/EventInformationCard.tsx
@@ -43,6 +43,8 @@ interface EventInformationCardProps {
   photos: AdminPhoto[];
   phoneFieldEnabled: boolean;
   daysUntilExpiration: number | null;
+  // Reveal mode (#838): stamps revealed_at via POST /events/:id/reveal
+  onRevealNow?: () => void;
 }
 
 export const EventInformationCard: React.FC<EventInformationCardProps> = ({
@@ -58,7 +60,8 @@ export const EventInformationCard: React.FC<EventInformationCardProps> = ({
   categories,
   photos,
   phoneFieldEnabled,
-  daysUntilExpiration
+  daysUntilExpiration,
+  onRevealNow
 }) => {
   const { t } = useTranslation();
   const { format } = useLocalizedDate();
@@ -430,6 +433,42 @@ export const EventInformationCard: React.FC<EventInformationCardProps> = ({
             </div>
           )}
 
+          {/* Reveal mode (#838) — only meaningful with guest uploads */}
+          {editForm.allow_user_uploads && (
+            <div>
+              <label className="flex items-center">
+                <input
+                  type="checkbox"
+                  checked={editForm.reveal_mode}
+                  onChange={(e) => setEditForm(prev => ({ ...prev, reveal_mode: e.target.checked }))}
+                  className="w-4 h-4 text-accent border-neutral-300 dark:border-neutral-600 rounded focus:ring-primary-500"
+                />
+                <span className="ml-2 text-sm text-neutral-700 dark:text-neutral-300">
+                  {t('events.revealMode', 'Reveal mode (hide gallery until reveal)')}
+                </span>
+              </label>
+              <p className="text-xs text-neutral-500 dark:text-neutral-400 mt-1 ml-6">
+                {t('events.revealModeHelp', 'Guests can upload but see no photos until you reveal the gallery — manually or at the scheduled time. Slideshow and client access keep working.')}
+              </p>
+              {editForm.reveal_mode && (
+                <div className="mt-2 ml-6">
+                  <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-1">
+                    {t('events.revealAt', 'Scheduled reveal (optional)')}
+                  </label>
+                  <input
+                    type="datetime-local"
+                    value={editForm.reveal_at}
+                    onChange={(e) => setEditForm(prev => ({ ...prev, reveal_at: e.target.value }))}
+                    className="px-3 py-2 border border-neutral-300 dark:border-neutral-600 bg-white dark:bg-neutral-800 text-neutral-900 dark:text-neutral-100 rounded-lg focus:ring-2 focus:ring-primary-500"
+                  />
+                  <p className="text-xs text-neutral-500 dark:text-neutral-400 mt-1">
+                    {t('events.revealAtHelp', 'Leave empty to reveal manually with the "Reveal now" button.')}
+                  </p>
+                </div>
+              )}
+            </div>
+          )}
+
           {/* Feedback Settings */}
           <div className="mt-4 pt-4 border-t border-neutral-200 dark:border-neutral-700">
             <h3 className="text-sm font-semibold text-neutral-900 dark:text-neutral-100 mb-3">{t('feedback.settings.title', 'Guest Feedback Settings')}</h3>
@@ -834,6 +873,39 @@ export const EventInformationCard: React.FC<EventInformationCardProps> = ({
             </dd>
           </div>
 
+          {Boolean(event.reveal_mode) && (
+            <div>
+              <dt className="text-sm font-medium text-neutral-500 dark:text-neutral-400">{t('events.revealModeStatus', 'Reveal mode')}</dt>
+              <dd className="mt-1 text-sm text-neutral-900 dark:text-neutral-100">
+                {event.revealed_at ? (
+                  <span className="inline-flex items-center px-2 py-1 text-xs font-medium text-green-700 dark:text-green-300 bg-green-100 dark:bg-green-900/40 rounded">
+                    {t('events.revealed', 'Revealed')}
+                  </span>
+                ) : (
+                  <div className="space-y-2">
+                    <span className="inline-flex items-center px-2 py-1 text-xs font-medium text-amber-700 dark:text-amber-300 bg-amber-100 dark:bg-amber-900/40 rounded">
+                      {t('events.hiddenUntilReveal', 'Hidden from guests')}
+                    </span>
+                    {event.reveal_at && (
+                      <p className="text-xs text-neutral-600 dark:text-neutral-400">
+                        {t('events.revealScheduled', 'Scheduled: {{date}}', { date: new Date(event.reveal_at).toLocaleString() })}
+                      </p>
+                    )}
+                    {onRevealNow && (
+                      <button
+                        type="button"
+                        onClick={onRevealNow}
+                        className="block px-3 py-1.5 text-xs font-medium text-white bg-accent hover:bg-accent-dark rounded transition-colors"
+                      >
+                        {t('events.revealNow', 'Reveal now')}
+                      </button>
+                    )}
+                  </div>
+                )}
+              </dd>
+            </div>
+          )}
+
           {/* Download Protection Display */}
           <div className="pt-3 mt-3 border-t border-neutral-200 dark:border-neutral-700">
             <dt className="text-sm font-medium text-neutral-500 dark:text-neutral-400 flex items-center gap-2">
diff --git a/frontend/src/pages/admin/event-details/OverviewTab.tsx b/frontend/src/pages/admin/event-details/OverviewTab.tsx
index cd3c420c..9cede3b4 100644
--- a/frontend/src/pages/admin/event-details/OverviewTab.tsx
+++ b/frontend/src/pages/admin/event-details/OverviewTab.tsx
@@ -32,6 +32,7 @@ interface OverviewTabProps {
   photos: AdminPhoto[];
   phoneFieldEnabled: boolean;
   daysUntilExpiration: number | null;
+  onRevealNow?: () => void;
   refetchEvent: () => void;
   setActiveTab: (tab: EventDetailsTab) => void;
   setShowPasswordReset: (show: boolean) => void;
@@ -63,6 +64,7 @@ export const OverviewTab: React.FC<OverviewTabProps> = ({
   photos,
   phoneFieldEnabled,
   daysUntilExpiration,
+  onRevealNow,
   refetchEvent,
   setActiveTab,
   setShowPasswordReset,
@@ -100,6 +102,7 @@ export const OverviewTab: React.FC<OverviewTabProps> = ({
           photos={photos}
           phoneFieldEnabled={phoneFieldEnabled}
           daysUntilExpiration={daysUntilExpiration}
+          onRevealNow={onRevealNow}
         />
 
         {/* Share Link */}
diff --git a/frontend/src/pages/admin/event-details/types.ts b/frontend/src/pages/admin/event-details/types.ts
index 3f1806f7..71dec4f7 100644
--- a/frontend/src/pages/admin/event-details/types.ts
+++ b/frontend/src/pages/admin/event-details/types.ts
@@ -6,6 +6,9 @@ export type EditFormState = {
   css_template_id: number | null;
   expires_at: string;
   allow_user_uploads: boolean;
+  // Reveal mode (#838): reveal_at is a datetime-local input string ('' = none)
+  reveal_mode: boolean;
+  reveal_at: string;
   upload_category_id: number | null;
   hero_photo_id: number | null;
   customer_name: string;
@@ -54,6 +57,8 @@ export const INITIAL_EDIT_FORM: EditFormState = {
   css_template_id: null,
   expires_at: '',
   allow_user_uploads: false,
+  reveal_mode: false,
+  reveal_at: '',
   upload_category_id: null,
   hero_photo_id: null,
   customer_name: '',
diff --git a/frontend/src/pages/admin/workflows/WorkflowEditorPage.tsx b/frontend/src/pages/admin/workflows/WorkflowEditorPage.tsx
index 26ade706..e3ccceb4 100644
--- a/frontend/src/pages/admin/workflows/WorkflowEditorPage.tsx
+++ b/frontend/src/pages/admin/workflows/WorkflowEditorPage.tsx
@@ -32,7 +32,7 @@ const TRIGGERS = [
   'quote.sent', 'quote.accepted', 'quote.declined',
   'contract.sent', 'contract.signed',
   'event.date_approaching',
-  'gallery.published', 'gallery.expiring', 'gallery.expired',
+  'gallery.published', 'gallery.expiring', 'gallery.expired', 'gallery.revealed',
   'customer.created',
 ];
 
diff --git a/frontend/src/services/events.service.ts b/frontend/src/services/events.service.ts
index 0acc02bd..682b27d6 100644
--- a/frontend/src/services/events.service.ts
+++ b/frontend/src/services/events.service.ts
@@ -61,6 +61,9 @@ interface UpdateEventData {
   expires_at?: string;
   is_active?: boolean;
   allow_user_uploads?: boolean;
+  // Reveal mode (#838)
+  reveal_mode?: boolean;
+  reveal_at?: string | null;
   upload_category_id?: number | null;
   hero_photo_id?: number | null;
   source_mode?: 'managed' | 'reference';
@@ -129,6 +132,12 @@ export const eventsService = {
   },
 
   // Update event (admin)
+  // Reveal now (#838): stamps revealed_at so the gallery opens for guests.
+  async revealEvent(id: number): Promise<{ revealed_at: string }> {
+    const response = await api.post(`/admin/events/${id}/reveal`);
+    return response.data;
+  },
+
   async updateEvent(id: number, data: UpdateEventData): Promise<Event> {
     const response = await api.put<Event>(`/admin/events/${id}`, data);
     return response.data;
diff --git a/frontend/src/types/index.ts b/frontend/src/types/index.ts
index 0b45f394..f0715abf 100644
--- a/frontend/src/types/index.ts
+++ b/frontend/src/types/index.ts
@@ -28,6 +28,10 @@ export interface Event {
     uploaded_at: string;
   }>;
   allow_user_uploads?: boolean;
+  // Reveal mode (#838)
+  reveal_mode?: boolean;
+  reveal_at?: string | null;
+  revealed_at?: string | null;
   upload_category_id?: number | null;
   hero_photo_id?: number | null;
   total_views?: number;
@@ -208,6 +212,10 @@ export interface GalleryData {
   };
   categories?: PhotoCategory[];
   photos: Photo[];
+  // Reveal mode (#838): the server returns the event shell with photos: []
+  // and this flag while the gallery is hidden from guests.
+  hidden_until_reveal?: boolean;
+  reveal_at?: string | null;
 }
 
 export interface GalleryStats {