diff --git a/viewer/image_viewer/JFJochDiffractionImage.cpp b/viewer/image_viewer/JFJochDiffractionImage.cpp
index 5f7b3576..7c12ab74 100644
--- a/viewer/image_viewer/JFJochDiffractionImage.cpp
+++ b/viewer/image_viewer/JFJochDiffractionImage.cpp
@@ -1011,6 +1011,20 @@ QString JFJochDiffractionImage::HoverResolutionLabel() const {
     return QString("d = %1 \u00C5").arg(QString::number(hover_resolution, 'f', 2));
 }
 
+QString JFJochDiffractionImage::PixelLabel(int x, int y) const {
+    if (!image)
+        return {};
+
+    const int32_t v = image->Image()[static_cast<size_t>(y) * W + x];
+    if (v == GAP_PXL_VALUE)
+        return QStringLiteral("Gap");
+    if (v == ERROR_PXL_VALUE)
+        return QStringLiteral("Err");
+    if (v == SATURATED_PXL_VALUE)
+        return QStringLiteral("Sat");
+    return QString::number(v);
+}
+
 void JFJochDiffractionImage::drawForeground(QPainter *painter, const QRectF &rect) {
     JFJochImage::drawForeground(painter, rect);
 
diff --git a/viewer/image_viewer/JFJochDiffractionImage.h b/viewer/image_viewer/JFJochDiffractionImage.h
index c9a3f847..3ba3884e 100644
--- a/viewer/image_viewer/JFJochDiffractionImage.h
+++ b/viewer/image_viewer/JFJochDiffractionImage.h
@@ -26,6 +26,9 @@ Q_OBJECT
     // currently sits, in viewport coordinates.
     QRect hover_text_rect_;
     [[nodiscard]] QString HoverResolutionLabel() const;
+    // Counts are exact integers: label them from the int32 image rather than from a float copy,
+    // which both avoids materialising that copy and cannot round large summed values.
+    [[nodiscard]] QString PixelLabel(int x, int y) const override;
     void drawForeground(QPainter *painter, const QRectF &rect) override;
 public:
     enum class RingMode {Auto, Estimation, Manual, None, IceRings};
diff --git a/viewer/image_viewer/JFJochImage.cpp b/viewer/image_viewer/JFJochImage.cpp
index 26172d87..3ed3b9ed 100644
--- a/viewer/image_viewer/JFJochImage.cpp
+++ b/viewer/image_viewer/JFJochImage.cpp
@@ -817,86 +817,75 @@ void JFJochImage::applyViewport(QTransform transform, QPointF center) {
     m_applyingViewport = false;
 }
 
-void JFJochImage::writePixelLabels() {
-
-    static QFont font([] {
-        QFont f("DejaVu Sans Mono");
-        f.setStyleHint(QFont::TypeWriter);
-        f.setPixelSize(1);
-        return f;
-    }());
-    static const QString kGap = QStringLiteral("Gap");
-    static const QString kErr = QStringLiteral("Err");
-    static const QString kSat = QStringLiteral("Sat");
-
-    QRectF visibleRect = mapToScene(viewport()->geometry()).boundingRect();
-
-    const int startX = std::max(0, static_cast<int>(std::floor(visibleRect.left())));
-    const int endX   = std::min(static_cast<int>(W), static_cast<int>(std::ceil(visibleRect.right())));
-    const int startY = std::max(0, static_cast<int>(std::floor(visibleRect.top())));
-    const int endY   = std::min(static_cast<int>(H), static_cast<int>(std::ceil(visibleRect.bottom())));
-
-    const int visW = std::max(0, endX - startX);
-    const int visH = std::max(0, endY - startY);
-    int maxLabels = 5000;
-
+QString JFJochImage::PixelLabel(int x, int y) const {
     // Choose thresholds that fit your UI width
     constexpr float kMinFixed = 1e-3;
     constexpr float kMaxFixed = 1e5;
 
-    if (visW * visH  <= maxLabels) {
-        EnsurePixelValues();
+    const float val = image_fp[static_cast<size_t>(y) * W + x];
+    const auto absVal = std::abs(val);
+    const auto nearest = std::nearbyint(val);
 
-        QString numBuf; // reused buffer
+    if (std::isnan(val))
+        return QStringLiteral("Gap");
+    if (std::isinf(val))
+        return std::signbit(val) ? QStringLiteral("Err") : QStringLiteral("Sat");
+    if (val == 0.0f)
+        return QStringLiteral("0");
+    if (absVal >= kMinFixed && absVal < kMaxFixed) {
+        if (std::abs(val - nearest) < 1e-6)
+            return QString::number(static_cast<qint64>(val));
+        if (absVal < 1e4)
+            return QString::number(val, 'f', label_decimals_);
+        return QString::number(val, 'f', std::min(label_decimals_, 2));
+    }
+    return QString::number(val, 'e', 1);
+}
 
-        for (int y = startY; y < endY; y ++) {
-            for (int x = startX; x < endX; x++) {
-                const int idx = y * W + x;
-                const float val = image_fp[idx];
+void JFJochImage::drawPixelLabels(QPainter *painter) {
+    constexpr int kMaxLabels = 5000;
 
-                const auto absVal = std::abs(val);
-                const auto nearest = std::nearbyint(val);
+    const QRectF visibleRect = mapToScene(viewport()->rect()).boundingRect();
+    const int startX = std::max(0, static_cast<int>(std::floor(visibleRect.left())));
+    const int endX   = std::min(static_cast<int>(W), static_cast<int>(std::ceil(visibleRect.right())));
+    const int startY = std::max(0, static_cast<int>(std::floor(visibleRect.top())));
+    const int endY   = std::min(static_cast<int>(H), static_cast<int>(std::ceil(visibleRect.bottom())));
+    if (endX <= startX || endY <= startY)
+        return;
+    if ((endX - startX) * (endY - startY) > kMaxLabels)
+        return;
 
-                const QString* pText = nullptr;
-                if (std::isnan(val)) {
-                    pText = &kGap;
-                } else if (std::isinf(val)) {
-                    pText = std::signbit(val) ? &kErr : &kSat;
-                } else if (val == 0.0f) {
-                    numBuf = QStringLiteral("0");
-                    pText = &numBuf;
-                } else if (absVal >= kMinFixed && absVal < kMaxFixed) {
-                    if (std::abs(val - nearest) < 1e-6)
-                        numBuf = QString::number(static_cast<qint64>(val));
-                    else if (absVal < 1e4)
-                        numBuf = QString::number(val, 'f', label_decimals_);
-                    else
-                        numBuf = QString::number(val, 'f', std::min(label_decimals_, 2));
-                    pText = &numBuf;
-                } else {
-                    numBuf = QString::number(val, 'e', 1);
-                    pText = &numBuf;
-                }
+    // Laid out in viewport pixels: a constant, readable size independent of the zoom
+    painter->save();
+    painter->resetTransform();
 
-                auto *textItem = new QGraphicsSimpleTextItem(*pText);
-                textItem->setFont(font);
-                // Read the colour back from the rendered image rather than keeping a
-                // full-size mirror of it around for the few pixels that get a label.
-                const QRgb pxl = frame_->pixel(x, y);
-                if (luminance(rgb{.r = static_cast<uint8_t>(qRed(pxl)),
-                                  .g = static_cast<uint8_t>(qGreen(pxl)),
-                                  .b = static_cast<uint8_t>(qBlue(pxl))}) > 128.0)
-                    textItem->setBrush(Qt::black);
-                else
-                    textItem->setBrush(Qt::white);
+    QFont font("DejaVu Sans Mono");
+    font.setStyleHint(QFont::TypeWriter);
+    font.setPixelSize(std::clamp(static_cast<int>(scale_factor * 0.3), 7, 16));
+    painter->setFont(font);
 
-                textItem->setPos(x + 0.3, y + 0.2);
-                textItem->setTransform(QTransform::fromScale(0.2, 0.2));
-                scene()->addItem(textItem);
-                addOverlayItem(textItem);
-            }
+    for (int y = startY; y < endY; y++) {
+        for (int x = startX; x < endX; x++) {
+            const QRect cell = mapFromScene(QRectF(x, y, 1, 1)).boundingRect();
+            // Read the colour back from the rendered image rather than keeping a full-size
+            // mirror of it around for the few pixels that get a label.
+            const QRgb pxl = frame_->pixel(x, y);
+            painter->setPen(luminance(rgb{.r = static_cast<uint8_t>(qRed(pxl)),
+                                          .g = static_cast<uint8_t>(qGreen(pxl)),
+                                          .b = static_cast<uint8_t>(qBlue(pxl))}) > 128.0
+                            ? Qt::black : Qt::white);
+            painter->drawText(cell, Qt::AlignCenter, PixelLabel(x, y));
         }
     }
+
+    painter->restore();
+}
+
+void JFJochImage::drawForeground(QPainter *painter, const QRectF &rect) {
+    QGraphicsView::drawForeground(painter, rect);
+
+    if (scale_factor > 30.0 && W * H > 0 && frame_ && !frame_->isNull())
+        drawPixelLabels(painter);
 }
 
 void JFJochImage::resetScenePointers() {
@@ -928,9 +917,6 @@ void JFJochImage::updateOverlay() {
         image_dirty_ = false;
     }
 
-    if (scale_factor > 30.0)
-        writePixelLabels();
-
     DrawROI();
 
     addCustomOverlay();
diff --git a/viewer/image_viewer/JFJochImage.h b/viewer/image_viewer/JFJochImage.h
index b0b1da6d..acc6ea09 100644
--- a/viewer/image_viewer/JFJochImage.h
+++ b/viewer/image_viewer/JFJochImage.h
@@ -82,7 +82,7 @@ class JFJochImage : public QGraphicsView {
     void DrawROI();
     virtual void addCustomOverlay();
     void updateROI();
-    void writePixelLabels();
+    void drawPixelLabels(QPainter *painter);
     void wheelEvent(QWheelEvent* event) override;
     void resizeEvent(QResizeEvent *event) override;
     void contextMenuEvent(QContextMenuEvent *event) override;
@@ -156,6 +156,12 @@ protected:
     QPointF roiEndPos;
     QRectF roiBox;
 
+    // Text for the per-pixel value label at (x, y). The base reads image_fp, which is what the
+    // float-valued views hold; a view whose source is exact integers overrides this so the label
+    // is exact and no float copy of the image has to exist at all.
+    [[nodiscard]] virtual QString PixelLabel(int x, int y) const;
+    void drawForeground(QPainter *painter, const QRectF &rect) override;
+
     static QPointF RoundPoint(const QPointF& p);
     virtual void mouseHover(const QPointF &scenePos, Qt::KeyboardModifiers modifiers) = 0;