diff --git a/Plugins/Json/include/Acts/Plugins/Json/JsonGeometryConverter.hpp b/Plugins/Json/include/Acts/Plugins/Json/JsonGeometryConverter.hpp
index d3657080421743cd51b169eb8b345f3912acdb63..20dbc237540cb72b2aaa52734d8f72b3d52e8cb7 100644
--- a/Plugins/Json/include/Acts/Plugins/Json/JsonGeometryConverter.hpp
+++ b/Plugins/Json/include/Acts/Plugins/Json/JsonGeometryConverter.hpp
@@ -56,7 +56,7 @@ class JsonGeometryConverter {
 
     /// The LayerRep is actually worth it to write out
     operator bool() const {
-      return (sensitives.empty() or approaches.empty() or
+      return (!sensitives.empty() or !approaches.empty() or
               representing != nullptr);
     }
   };
@@ -76,7 +76,7 @@ class JsonGeometryConverter {
 
     /// The VolumeRep is actually worth it to write out
     operator bool() const {
-      return (layers.empty() or boundaries.empty() or material != nullptr);
+      return (!layers.empty() or !boundaries.empty() or material != nullptr);
     }
   };