diff --git a/exercises/exercise-model/main.cc b/exercises/exercise-model/main.cc
index fe747afe049368be973a292d60ab756984e9c2cf..a036a6eb2e06a20534a69d371fc1ac61ca6bd325 100644
--- a/exercises/exercise-model/main.cc
+++ b/exercises/exercise-model/main.cc
@@ -161,7 +161,7 @@ int main(int argc, char** argv)
 
     // We initialize the VTK output module and write out the initial concentration field
     // VtkOutputModule<GridVariables, SolutionVector> vtkWriter(*gridVariables, sol, problem->name());
-    // vtkWriter.addVolumeVariable([](const auto& vv){ return vv.imageIntensity(); }, "imageIntensity");
+    // vtkWriter.addVolumeVariable([](const auto& vv){ return vv.priVar(0); }, "imageIntensity");
     // vtkWriter.write(0.0);
 
     // We instantiate time loop using start and end time as well as