diff --git a/image_analysis/WriteMmcif.cpp b/image_analysis/WriteMmcif.cpp
index 28b4d994..841e534b 100644
--- a/image_analysis/WriteMmcif.cpp
+++ b/image_analysis/WriteMmcif.cpp
@@ -89,12 +89,12 @@ void WriteMmcifReflections(std::ostream& out,
 
     // ---------- _diffrn_source / _diffrn_detector ----------
     if (meta.source.has_value()) {
-        out << "_diffrn_source.pdbx_synchrotron_site"
+        out << "_diffrn_source.pdbx_synchrotron_site  "
             << CifStr(meta.source.value()) << "\n";
     }
 
     if (meta.beamline.has_value()) {
-        out << "_diffrn_source.pdbx_synchrotron_beamline"
+        out << "_diffrn_source.pdbx_synchrotron_beamline  "
             << CifStr(meta.beamline.value()) << "\n";
     }