diff --git a/src/include/stir/recon_buildblock/LogcoshPrior.h b/src/include/stir/recon_buildblock/LogcoshPrior.h
index 0b2dfb45d..5b5715264 100644
--- a/src/include/stir/recon_buildblock/LogcoshPrior.h
+++ b/src/include/stir/recon_buildblock/LogcoshPrior.h
@@ -175,6 +175,9 @@ class LogcoshPrior : public RegisteredParsingObject<LogcoshPrior<elemT>,
   void initialise_keymap() override;
   bool post_processing() override;
 
+  //! Check that the prior is ready to be used
+  void check(DiscretisedDensity<3, elemT> const& current_image_estimate) const override;
+
 private:
   //! Spatially variant penalty penalty image ptr
   shared_ptr<DiscretisedDensity<3, elemT>> kappa_ptr;
diff --git a/src/recon_buildblock/LogcoshPrior.cxx b/src/recon_buildblock/LogcoshPrior.cxx
index 0876407ea..68c3a602a 100644
--- a/src/recon_buildblock/LogcoshPrior.cxx
+++ b/src/recon_buildblock/LogcoshPrior.cxx
@@ -142,6 +142,21 @@ LogcoshPrior<elemT>::LogcoshPrior(const bool only_2D_v, float penalisation_facto
   this->scalar = scalar_v;
 }
 
+template <typename elemT>
+void
+LogcoshPrior<elemT>::check(DiscretisedDensity<3, elemT> const& current_image_estimate) const
+{
+  // Do base-class check
+  base_type::check(current_image_estimate);
+  if (!is_null_ptr(this->kappa_ptr))
+    {
+      std::string explanation;
+      if (!this->kappa_ptr->has_same_characteristics(current_image_estimate, explanation))
+        error(std::string(registered_name)
+              + ": kappa image does not have the same index range as the reconstructed image:" + explanation);
+    }
+}
+
 template <typename elemT>
 bool
 LogcoshPrior<elemT>::is_convex() const
@@ -251,9 +266,6 @@ LogcoshPrior<elemT>::compute_value(const DiscretisedDensity<3, elemT>& current_i
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("LogcoshPrior: kappa image has not the same index range as the reconstructed image\n");
-
   double result = 0.;
   const int min_z = current_image_estimate.get_min_index();
   const int max_z = current_image_estimate.get_max_index();
@@ -323,8 +335,6 @@ LogcoshPrior<elemT>::compute_gradient(DiscretisedDensity<3, elemT>& prior_gradie
     }
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("LogcoshPrior: kappa image has not the same index range as the reconstructed image\n");
 
   const int min_z = current_image_estimate.get_min_index();
   const int max_z = current_image_estimate.get_max_index();
@@ -409,9 +419,6 @@ LogcoshPrior<elemT>::compute_Hessian(DiscretisedDensity<3, elemT>& prior_Hessian
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("LogcoshPrior: kappa image has not the same index range as the reconstructed image\n");
-
   const int z = coords[1];
   const int y = coords[2];
   const int x = coords[3];
@@ -479,9 +486,6 @@ LogcoshPrior<elemT>::parabolic_surrogate_curvature(DiscretisedDensity<3, elemT>&
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("LogcoshPrior: kappa image has not the same index range as the reconstructed image\n");
-
   const int min_z = current_image_estimate.get_min_index();
   const int max_z = current_image_estimate.get_max_index();
   for (int z = min_z; z <= max_z; z++)
@@ -550,9 +554,6 @@ LogcoshPrior<elemT>::accumulate_Hessian_times_input(DiscretisedDensity<3, elemT>
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(input))
-    error("LogcoshPrior: kappa image has not the same index range as the reconstructed image\n");
-
   const int min_z = output.get_min_index();
   const int max_z = output.get_max_index();
   for (int z = min_z; z <= max_z; z++)
diff --git a/src/recon_buildblock/PLSPrior.cxx b/src/recon_buildblock/PLSPrior.cxx
index 6ff213b1a..505a2c397 100644
--- a/src/recon_buildblock/PLSPrior.cxx
+++ b/src/recon_buildblock/PLSPrior.cxx
@@ -121,6 +121,13 @@ PLSPrior<elemT>::check(DiscretisedDensity<3, elemT> const& current_image_estimat
   // Check anatomical and current image have same characteristics
   if (!this->anatomical_sptr->has_same_characteristics(current_image_estimate))
     error("The anatomical image must have the same charateristics as the PET image");
+  if (!is_null_ptr(this->kappa_ptr))
+    {
+      std::string explanation;
+      if (!this->kappa_ptr->has_same_characteristics(current_image_estimate, explanation))
+        error(std::string(registered_name)
+              + ": kappa image does not have the same index range as the reconstructed image:" + explanation);
+    }
 }
 
 template <typename elemT>
@@ -471,9 +478,6 @@ PLSPrior<elemT>::compute_value(const DiscretisedDensity<3, elemT>& current_image
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("PLSPrior: kappa image has not the same index range as the reconstructed image\n");
-
   double result = 0.;
   const int min_z = current_image_estimate.get_min_index();
   const int max_z = current_image_estimate.get_max_index();
@@ -545,8 +549,6 @@ PLSPrior<elemT>::compute_gradient(DiscretisedDensity<3, elemT>& prior_gradient,
       *inner_product_sptr, *penalty_sptr, *pet_im_grad_z_sptr, *pet_im_grad_y_sptr, *pet_im_grad_x_sptr, current_image_estimate);
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("PLSPrior: kappa image has not the same index range as the reconstructed image\n");
   shared_ptr<DiscretisedDensity<3, elemT>> gradient_sptr(this->anatomical_sptr->get_empty_copy());
 
   const int min_z = current_image_estimate.get_min_index();
diff --git a/src/recon_buildblock/QuadraticPrior.cxx b/src/recon_buildblock/QuadraticPrior.cxx
index 2a070a294..69322c832 100644
--- a/src/recon_buildblock/QuadraticPrior.cxx
+++ b/src/recon_buildblock/QuadraticPrior.cxx
@@ -118,6 +118,13 @@ QuadraticPrior<elemT>::check(DiscretisedDensity<3, elemT> const& current_image_e
 {
   // Do base-class check
   base_type::check(current_image_estimate);
+  if (!is_null_ptr(this->kappa_ptr))
+    {
+      std::string explanation;
+      if (!this->kappa_ptr->has_same_characteristics(current_image_estimate, explanation))
+        error(std::string(registered_name)
+              + ": kappa image does not have the same index range as the reconstructed image:" + explanation);
+    }
 }
 
 template <typename elemT>
@@ -241,9 +248,6 @@ QuadraticPrior<elemT>::compute_value(const DiscretisedDensity<3, elemT>& current
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("QuadraticPrior: kappa image has not the same index range as the reconstructed image\n");
-
   double result = 0.;
   const int min_z = current_image_estimate.get_min_index();
   const int max_z = current_image_estimate.get_max_index();
@@ -316,8 +320,6 @@ QuadraticPrior<elemT>::compute_gradient(DiscretisedDensity<3, elemT>& prior_grad
     }
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("QuadraticPrior: kappa image has not the same index range as the reconstructed image\n");
 
   const int min_z = current_image_estimate.get_min_index();
   const int max_z = current_image_estimate.get_max_index();
@@ -407,9 +409,6 @@ QuadraticPrior<elemT>::compute_Hessian(DiscretisedDensity<3, elemT>& prior_Hessi
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("QuadraticPrior: kappa image has not the same index range as the reconstructed image\n");
-
   const int z = coords[1];
   const int y = coords[2];
   const int x = coords[3];
@@ -479,9 +478,6 @@ QuadraticPrior<elemT>::parabolic_surrogate_curvature(DiscretisedDensity<3, elemT
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("QuadraticPrior: kappa image has not the same index range as the reconstructed image\n");
-
   const int min_z = current_image_estimate.get_min_index();
   const int max_z = current_image_estimate.get_max_index();
   for (int z = min_z; z <= max_z; z++)
@@ -559,9 +555,6 @@ QuadraticPrior<elemT>::add_multiplication_with_approximate_Hessian(DiscretisedDe
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(input))
-    error("QuadraticPrior: kappa image has not the same index range as the reconstructed image\n");
-
   const int min_z = output.get_min_index();
   const int max_z = output.get_max_index();
   for (int z = min_z; z <= max_z; z++)
@@ -629,9 +622,6 @@ QuadraticPrior<elemT>::accumulate_Hessian_times_input(DiscretisedDensity<3, elem
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(input))
-    error("QuadraticPrior: kappa image has not the same index range as the reconstructed image\n");
-
   const int min_z = output.get_min_index();
   const int max_z = output.get_max_index();
   for (int z = min_z; z <= max_z; z++)
diff --git a/src/recon_buildblock/RelativeDifferencePrior.cxx b/src/recon_buildblock/RelativeDifferencePrior.cxx
index 3961aee7a..a25e44507 100644
--- a/src/recon_buildblock/RelativeDifferencePrior.cxx
+++ b/src/recon_buildblock/RelativeDifferencePrior.cxx
@@ -122,6 +122,13 @@ RelativeDifferencePrior<elemT>::check(DiscretisedDensity<3, elemT> const& curren
 {
   // Do base-class check
   base_type::check(current_image_estimate);
+  if (!is_null_ptr(this->kappa_ptr))
+    {
+      std::string explanation;
+      if (!this->kappa_ptr->has_same_characteristics(current_image_estimate, explanation))
+        error(std::string(registered_name)
+              + ": kappa image does not have the same index range as the reconstructed image:" + explanation);
+    }
 }
 
 template <typename elemT>
@@ -312,9 +319,6 @@ RelativeDifferencePrior<elemT>::compute_value(const DiscretisedDensity<3, elemT>
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("RelativeDifferencePrior: kappa image has not the same index range as the reconstructed image\n");
-
   double result = 0.;
   const int min_z = current_image_estimate.get_min_index();
   const int max_z = current_image_estimate.get_max_index();
@@ -389,8 +393,6 @@ RelativeDifferencePrior<elemT>::compute_gradient(DiscretisedDensity<3, elemT>& p
     }
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
-  if (do_kappa && !kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("RelativeDifferencePrior: kappa image has not the same index range as the reconstructed image\n");
 
   const int min_z = current_image_estimate.get_min_index();
   const int max_z = current_image_estimate.get_max_index();
@@ -475,9 +477,6 @@ RelativeDifferencePrior<elemT>::compute_Hessian(DiscretisedDensity<3, elemT>& pr
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && kappa_ptr->has_same_characteristics(current_image_estimate))
-    error("RelativeDifferencePrior: kappa image has not the same index range as the reconstructed image\n");
-
   const int z = coords[1];
   const int y = coords[2];
   const int x = coords[3];
@@ -554,9 +553,6 @@ RelativeDifferencePrior<elemT>::accumulate_Hessian_times_input(DiscretisedDensit
 
   const bool do_kappa = !is_null_ptr(kappa_ptr);
 
-  if (do_kappa && !kappa_ptr->has_same_characteristics(input))
-    error("RelativeDifferencePrior: kappa image has not the same index range as the reconstructed image\n");
-
   const int min_z = output.get_min_index();
   const int max_z = output.get_max_index();
   for (int z = min_z; z <= max_z; z++)