diff --git a/common/JFJochMessages.h b/common/JFJochMessages.h
index 0bbedfda..3d25da43 100644
--- a/common/JFJochMessages.h
+++ b/common/JFJochMessages.h
@@ -295,6 +295,8 @@ struct EndMessage {
 
     std::optional<LatticeMessage> rotation_lattice_type;
     std::optional<CrystalLattice> rotation_lattice;
+
+    std::vector<float> scale_factor;
 };
 
 struct MetadataMessage {
diff --git a/frame_serialize/CBORStream2Deserializer.cpp b/frame_serialize/CBORStream2Deserializer.cpp
index b265e51d..036daf00 100644
--- a/frame_serialize/CBORStream2Deserializer.cpp
+++ b/frame_serialize/CBORStream2Deserializer.cpp
@@ -1261,6 +1261,8 @@ namespace {
                 message.bkg_estimate = GetCBORFloat(value);
             else if (key == "indexing_rate")
                 message.indexing_rate = GetCBORFloat(value);
+            else if (key == "image_scale_factor")
+                GetCBORFloatArray(value, message.scale_factor);
             else if (key == "rotation_lattice") {
                 std::vector<float> tmp;
                 GetCBORFloatArray(value, tmp);
diff --git a/frame_serialize/CBORStream2Serializer.cpp b/frame_serialize/CBORStream2Serializer.cpp
index fd2d8212..16e8e2c9 100644
--- a/frame_serialize/CBORStream2Serializer.cpp
+++ b/frame_serialize/CBORStream2Serializer.cpp
@@ -676,6 +676,7 @@ void CBORStream2Serializer::SerializeSequenceEnd(const EndMessage& message) {
 
     CBOR_ENC(mapEncoder, "rotation_lattice_type", message.rotation_lattice_type);
     CBOR_ENC(mapEncoder, "rotation_lattice", message.rotation_lattice->GetVector());
+    CBOR_ENC(mapEncoder, "image_scale_factor", message.scale_factor);
     cborErr(cbor_encoder_close_container(&encoder, &mapEncoder));
 
     curr_size = cbor_encoder_get_buffer_size(&encoder, buffer);
diff --git a/writer/HDF5NXmx.cpp b/writer/HDF5NXmx.cpp
index ce60cab4..15cac4ab 100644
--- a/writer/HDF5NXmx.cpp
+++ b/writer/HDF5NXmx.cpp
@@ -711,6 +711,9 @@ void NXmx::Finalize(const EndMessage &end) {
     if (end.bkg_estimate) {
         SaveScalar(*hdf5_file, "/entry/MX/bkgEstimateMean", end.bkg_estimate.value());
     }
+
+    if (!end.scale_factor.empty())
+        SaveVector(*hdf5_file, "/entry/MX/imageScaleFactor", end.scale_factor);
 }
 
 void NXmx::UserData(const StartMessage &start) {