diff --git a/public/admin.html b/public/admin.html
index 1d9c6c7..fd822cd 100644
--- a/public/admin.html
+++ b/public/admin.html
@@ -125,6 +125,7 @@
       <div class="spacer"></div>
       <span id="dirty" title="unsaved changes"></span>
       <button id="reloadBtn" title="Discard changes and reload from server">Reload</button>
+      <button id="printAnchorsBtn" title="Open printable anchor markers">Print anchors</button>
       <button id="exportBtn" title="Download scene.json">Export</button>
       <button id="saveBtn" class="primary" disabled>Save to server</button>
     </div>
diff --git a/public/anchors-print.html b/public/anchors-print.html
new file mode 100644
index 0000000..42411a0
--- /dev/null
+++ b/public/anchors-print.html
@@ -0,0 +1,210 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="utf-8" />
+<meta name="viewport" content="width=device-width, initial-scale=1" />
+<title>Newbury Crests — print sheet</title>
+<style>
+  :root { --ink:#11131c; --dim:#666; --line:#ccc;
+    --red:#f65151; --yellow:#fff35d; --blue:#529eff; }
+  * { box-sizing: border-box; }
+  html, body { margin: 0; background: #f4f5f7; color: var(--ink);
+    font-family: 'Inter', system-ui, sans-serif; }
+
+  /* screen-only control bar */
+  #bar { position: sticky; top: 0; z-index: 10; background: #fff;
+    border-bottom: 1px solid var(--line); padding: 10px 16px; display: flex;
+    align-items: center; gap: 14px; flex-wrap: wrap; box-shadow: 0 1px 4px rgba(0,0,0,0.06); }
+  #bar h1 { font-size: 15px; margin: 0; font-weight: 700; }
+  #bar h1 span { color: var(--blue); }
+  #bar .spacer { flex: 1; }
+  #bar label { font-size: 12px; color: var(--dim); display: flex; align-items: center; gap: 5px; }
+  #bar input[type=number] { width: 62px; padding: 4px 6px; border: 1px solid var(--line);
+    border-radius: 6px; font-family: ui-monospace, monospace; font-size: 12px; }
+  #bar button { border: 0; cursor: pointer; font-weight: 600; font-size: 13px;
+    padding: 8px 16px; border-radius: 8px; background: #111827; color: #fff; }
+  #bar button.ghost { background: #eef0f4; color: #111827; }
+  #bar .note { font-size: 11px; color: var(--dim); flex-basis: 100%; }
+
+  #sheet { padding: 16px; }
+  .card { background: #fff; border: 1px solid #e3e5ea; border-radius: 10px;
+    padding: 14px; margin: 0 auto 14px; max-width: 560px; }
+  .card .meta { display: flex; justify-content: space-between; align-items: baseline;
+    margin-bottom: 10px; }
+  .card .name { font-weight: 700; font-size: 14px; }
+  .card .sub { font-family: ui-monospace, monospace; font-size: 11px; color: var(--dim); }
+  .marker-wrap { display: flex; gap: 16px; align-items: center; }
+  .marker-wrap svg { display: block; }
+  .card .facts { font-size: 11px; color: var(--dim); line-height: 1.6; }
+  .card .facts b { color: var(--ink); }
+  .warn { color: #b45309; font-size: 11px; margin-top: 6px; }
+  #empty { text-align: center; color: var(--dim); padding: 60px 20px; }
+
+  @media print {
+    #bar { display: none; }
+    body, html { background: #fff; }
+    #sheet { padding: 0; }
+    .card { border: none; box-shadow: none; page-break-inside: avoid;
+      max-width: none; margin: 0 0 8mm; padding: 0; }
+    /* cut guides show in print */
+  }
+</style>
+</head>
+<body>
+  <div id="bar">
+    <h1>Newbury <span>Crests</span> — print sheet</h1>
+    <div class="spacer"></div>
+    <label>cell size
+      <input id="cellMm" type="number" value="16" min="6" max="40" step="1" /> mm
+    </label>
+    <label><input id="showRing" type="checkbox" checked /> colour ring</label>
+    <label><input id="showGuides" type="checkbox" checked /> cut guides</label>
+    <button class="ghost" id="reloadBtn">Reload anchors</button>
+    <button id="printBtn">Print</button>
+    <div class="note">Print at <b>100% / actual size</b> (no "fit to page"). Measure a printed marker to confirm scale before building. Matte paper or matte UV — avoid gloss (glare breaks detection).</div>
+  </div>
+
+  <div id="sheet"><div id="empty">Loading anchors…</div></div>
+
+  <!-- vendored ArUco dictionary for the exact bit patterns -->
+  <script src="vendor/dictionaries/aruco_4x4_1000.js"></script>
+  <script>
+  (function () {
+    'use strict';
+    const LURE = { Red: '#f65151', Yellow: '#fff35d', Blue: '#529eff' };
+    const RING_CYCLE = ['Red', 'Yellow', 'Blue'];
+    const DPI = 96;                 // CSS px per inch
+    const MM_PER_IN = 25.4;
+    const pxPerMm = DPI / MM_PER_IN; // ~3.78 px/mm at 96dpi
+
+    // Build a 6x6 bit grid (0=black,1=white) for an ArUco 4x4 id.
+    // Outer ring is the quiet border (all black); inner 4x4 = the code bits.
+    function grid6(id) {
+      const dict = (window.AR && AR.DICTIONARIES && AR.DICTIONARIES.ARUCO_4X4_1000)
+        ? AR.DICTIONARIES.ARUCO_4X4_1000 : null;
+      // js-aruco exposes the dictionary via AR.Dictionary; build one to read codeList
+      const d = new AR.Dictionary('ARUCO_4X4_1000');
+      const code = d.codeList[id];
+      if (!code) return null;
+      const g = [];
+      for (let y = -1; y <= 4; y++) {
+        const row = [];
+        for (let x = -1; x <= 4; x++) {
+          if (y < 0 || y > 3 || x < 0 || x > 3) row.push(0);   // black border
+          else row.push(code[y * 4 + x] === '1' ? 1 : 0);       // data bit
+        }
+        g.push(row);
+      }
+      return g;
+    }
+
+    function markerSVG(id, cellMm, showRing, showGuides) {
+      const core = grid6(id);
+      if (!core) return `<div class="warn">No pattern for id ${id} (out of range).</div>`;
+      const cell = cellMm * pxPerMm;
+      const ringCells = showRing ? 1 : 0;
+      const n = 6 + ringCells * 2;               // total cells across
+      const dim = n * cell;
+      const guide = showGuides ? cell * 0.5 : 0;  // margin for cut guides
+      const total = dim + guide * 2;
+
+      let s = `<svg width="${total}" height="${total}" viewBox="0 0 ${total} ${total}" xmlns="http://www.w3.org/2000/svg">`;
+      s += `<rect width="${total}" height="${total}" fill="#ffffff"/>`;
+
+      // colour-wheel ring (decorative, outside the detector core)
+      if (showRing) {
+        let ci = 0;
+        for (let y = 0; y < n; y++) for (let x = 0; x < n; x++) {
+          const isRing = (x === 0 || y === 0 || x === n - 1 || y === n - 1);
+          if (!isRing) continue;
+          const col = LURE[RING_CYCLE[ci % RING_CYCLE.length]]; ci++;
+          s += `<rect x="${guide + x * cell}" y="${guide + y * cell}" width="${cell}" height="${cell}" fill="${col}"/>`;
+        }
+      }
+
+      // detector core 6x6 (inset by the ring)
+      for (let y = 0; y < 6; y++) for (let x = 0; x < 6; x++) {
+        const fill = core[y][x] ? '#ffffff' : '#000000';
+        const px = guide + (x + ringCells) * cell;
+        const py = guide + (y + ringCells) * cell;
+        s += `<rect x="${px}" y="${py}" width="${cell}" height="${cell}" fill="${fill}"/>`;
+      }
+
+      // cut guides (corner crop marks)
+      if (showGuides) {
+        const gl = guide * 0.8, gt = 1;
+        const marks = [
+          [0, 0, 1, 1], [total, 0, -1, 1], [0, total, 1, -1], [total, total, -1, -1],
+        ];
+        for (const [cx, cy, dx, dy] of marks) {
+          s += `<line x1="${cx}" y1="${cy}" x2="${cx + dx * gl}" y2="${cy}" stroke="#999" stroke-width="${gt}"/>`;
+          s += `<line x1="${cx}" y1="${cy}" x2="${cx}" y2="${cy + dy * gl}" stroke="#999" stroke-width="${gt}"/>`;
+        }
+      }
+      s += '</svg>';
+      return s;
+    }
+
+    let anchors = [];
+    async function loadAnchors() {
+      const el = document.getElementById('sheet');
+      try {
+        const res = await fetch('/api/scene');
+        const scene = await res.json();
+        anchors = scene.anchors || [];
+      } catch (e) {
+        el.innerHTML = `<div id="empty">Couldn't load /api/scene: ${e.message}</div>`;
+        return;
+      }
+      render();
+    }
+
+    function render() {
+      const el = document.getElementById('sheet');
+      const cellMm = parseFloat(document.getElementById('cellMm').value) || 16;
+      const showRing = document.getElementById('showRing').checked;
+      const showGuides = document.getElementById('showGuides').checked;
+
+      if (!anchors.length) { el.innerHTML = `<div id="empty">No anchors in the scene yet. Add some in the workshop, then reload.</div>`; return; }
+
+      el.innerHTML = anchors.map((a) => {
+        const id = a.fiducialId ?? 0;
+        const coreMm = cellMm * 6;
+        const fullMm = showRing ? cellMm * 8 : coreMm;
+        const typeWarn = (a.fiducialType && a.fiducialType !== 'aruco')
+          ? `<div class="warn">⚠ This anchor is set to "${a.fiducialType}", but detection uses ArUco 4×4. Set it to <b>aruco</b> in the workshop, or this printed marker won't match.</div>`
+          : '';
+        const scaleWarn = (a.fiducialSizeMm && Math.abs(a.fiducialSizeMm - coreMm) > 1)
+          ? `<div class="warn">⚠ Anchor size is <b>${a.fiducialSizeMm}mm</b> but this prints the core at <b>${coreMm}mm</b> (cell ${cellMm}×6). Match them so pose scale is right: set cell to ${(a.fiducialSizeMm/6).toFixed(1)}mm or the anchor size to ${coreMm}mm.</div>`
+          : '';
+        return `
+          <div class="card">
+            <div class="meta">
+              <span class="name">${a.label || a.id}</span>
+              <span class="sub">ArUco 4×4 · id ${id}</span>
+            </div>
+            <div class="marker-wrap">
+              ${markerSVG(id, cellMm, showRing, showGuides)}
+              <div class="facts">
+                core <b>${coreMm}mm</b> (6×${cellMm}mm)<br/>
+                ${showRing ? `with ring <b>${fullMm}mm</b><br/>` : ''}
+                world pos <b>${Math.round(a.position?.x ?? 0)}, ${Math.round(a.position?.z ?? 0)}</b> mm<br/>
+                anchor id <span class="sub">${a.id}</span>
+              </div>
+            </div>
+            ${typeWarn}${scaleWarn}
+          </div>`;
+      }).join('');
+    }
+
+    document.getElementById('cellMm').addEventListener('input', render);
+    document.getElementById('showRing').addEventListener('change', render);
+    document.getElementById('showGuides').addEventListener('change', render);
+    document.getElementById('reloadBtn').addEventListener('click', loadAnchors);
+    document.getElementById('printBtn').addEventListener('click', () => window.print());
+
+    loadAnchors();
+  })();
+  </script>
+</body>
+</html>
diff --git a/public/js/admin.js b/public/js/admin.js
index f7c747a..9211042 100644
--- a/public/js/admin.js
+++ b/public/js/admin.js
@@ -721,6 +721,12 @@ $('reloadBtn').addEventListener('click', async () => {
   toast('Reloaded from server');
 });
 
+const printAnchorsBtn = document.getElementById('printAnchorsBtn');
+if (printAnchorsBtn) printAnchorsBtn.addEventListener('click', () => {
+  if (dirty) toast('Tip: save first so the print sheet matches your latest anchors', '');
+  window.open('anchors-print.html', '_blank');
+});
+
 window.addEventListener('beforeunload', (e) => { if (dirty) { e.preventDefault(); e.returnValue = ''; } });
 
 // ===========================================================================
