diff --git a/masque/file/gdsii.py b/masque/file/gdsii.py
index d37a634..a28979d 100644
--- a/masque/file/gdsii.py
+++ b/masque/file/gdsii.py
@@ -409,8 +409,8 @@ def _annotations_to_properties(annotations: annotations_t, max_len: int = 126) -
     for key, vals in annotations.items():
         try:
             i = int(key)
-        except ValueError:
-            raise PatternError(f'Annotation key {key} is not convertable to an integer')
+        except ValueError as err:
+            raise PatternError(f'Annotation key {key} is not convertable to an integer') from err
         if not (0 < i < 126):
             raise PatternError(f'Annotation key {key} converts to {i} (must be in the range [1,125])')
 
diff --git a/masque/file/oasis.py b/masque/file/oasis.py
index 10064b9..ad08623 100644
--- a/masque/file/oasis.py
+++ b/masque/file/oasis.py
@@ -298,7 +298,7 @@ def read(
                 cap_start = path_cap_map[element.get_extension_start()[0]]
                 cap_end   = path_cap_map[element.get_extension_end()[0]]
                 if cap_start != cap_end:
-                    raise Exception('masque does not support multiple cap types on a single path.')      # TODO handle multiple cap types
+                    raise PatternError('masque does not support multiple cap types on a single path.')      # TODO handle multiple cap types
                 cap = cap_start
 
                 path_args: dict[str, Any] = {}
diff --git a/masque/pattern.py b/masque/pattern.py
index 637b953..0c3b6cb 100644
--- a/masque/pattern.py
+++ b/masque/pattern.py
@@ -1016,10 +1016,10 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         try:
             from matplotlib import pyplot       # type: ignore
             import matplotlib.collections       # type: ignore
-        except ImportError as err:
-            logger.error('Pattern.visualize() depends on matplotlib!')
-            logger.error('Make sure to install masque with the [visualize] option to pull in the needed dependencies.')
-            raise err
+        except ImportError:
+            logger.exception('Pattern.visualize() depends on matplotlib!\n'
+                + 'Make sure to install masque with the [visualize] option to pull in the needed dependencies.')
+            raise
 
         if self.has_refs() and library is None:
             raise PatternError('Must provide a library when visualizing a pattern with refs')
diff --git a/masque/shapes/path.py b/masque/shapes/path.py
index 67f750e..bfaf14f 100644
--- a/masque/shapes/path.py
+++ b/masque/shapes/path.py
@@ -105,11 +105,11 @@ class Path(Shape):
         custom_caps = (PathCap.SquareCustom,)
         if self.cap in custom_caps:
             if vals is None:
-                raise Exception('Tried to set cap extensions to None on path with custom cap type')
+                raise PatternError('Tried to set cap extensions to None on path with custom cap type')
             self._cap_extensions = numpy.array(vals, dtype=float)
         else:
             if vals is not None:
-                raise Exception('Tried to set custom cap extensions on path with non-custom cap type')
+                raise PatternError('Tried to set custom cap extensions on path with non-custom cap type')
             self._cap_extensions = vals
 
     # vertices property
diff --git a/masque/shapes/text.py b/masque/shapes/text.py
index 5453c51..fa0038b 100644
--- a/masque/shapes/text.py
+++ b/masque/shapes/text.py
@@ -221,7 +221,7 @@ def get_char_as_polygons(
         'advance' distance (distance from the start of this glyph to the start of the next one)
     """
     if len(char) != 1:
-        raise Exception('get_char_as_polygons called with non-char')
+        raise PatternError('get_char_as_polygons called with non-char')
 
     face = Face(font_path)
     face.set_char_size(resolution)