diff --git a/ocrd_models/ocrd_models/ocrd_mets.py b/ocrd_models/ocrd_models/ocrd_mets.py
index 8571254e56..b42fa1ad13 100644
--- a/ocrd_models/ocrd_models/ocrd_mets.py
+++ b/ocrd_models/ocrd_models/ocrd_mets.py
@@ -3,6 +3,7 @@
 """
 from datetime import datetime
 import re
+import typing
 from lxml import etree as ET
 
 from ocrd_utils import (
@@ -159,22 +160,21 @@ def find_files(self, ID=None, fileGrp=None, pageId=None, mimetype=None, url=None
         Yields:
             :py:class:`ocrd_models:ocrd_file:OcrdFile` instantiations
         """
+        pageId_list = []
         if pageId:
-            if pageId.startswith(REGEX_PREFIX):
-                pageIds, pageId = re.compile(pageId[REGEX_PREFIX_LEN:]), list()
-            else:
-                pageIds, pageId = pageId.split(','), list()
-                pageIds_expanded = []
-                for pageId_ in pageIds:
-                    if '..' in pageId_:
-                        pageIds_expanded += generate_range(*pageId_.split('..', 1))
-                pageIds += pageIds_expanded
+            pageId_patterns = []
+            for pageId_token in re.split(r',', pageId):
+                if pageId_token.startswith(REGEX_PREFIX):
+                    pageId_patterns.append(re.compile(pageId_token[REGEX_PREFIX_LEN:]))
+                elif '..' in pageId_token:
+                    pageId_patterns += generate_range(*pageId_token.split('..', 1))
+                else:
+                    pageId_patterns += [pageId_token]
             for page in self._tree.getroot().xpath(
                 '//mets:div[@TYPE="page"]', namespaces=NS):
-                if (page.get('ID') in pageIds if isinstance(pageIds, list) else
-                    pageIds.fullmatch(page.get('ID'))):
-                    pageId.extend(
-                        [fptr.get('FILEID') for fptr in page.findall('mets:fptr', NS)])
+                if page.get('ID') in pageId_patterns or \
+                    any([isinstance(p, typing.Pattern) and p.fullmatch(page.get('ID')) for p in pageId_patterns]):
+                    pageId_list += [fptr.get('FILEID') for fptr in page.findall('mets:fptr', NS)]
         if ID and ID.startswith(REGEX_PREFIX):
             ID = re.compile(ID[REGEX_PREFIX_LEN:])
         if fileGrp and fileGrp.startswith(REGEX_PREFIX):
@@ -190,7 +190,7 @@ def find_files(self, ID=None, fileGrp=None, pageId=None, mimetype=None, url=None
                 else:
                     if not ID.fullmatch(cand.get('ID')): continue
 
-            if pageId is not None and cand.get('ID') not in pageId:
+            if pageId is not None and cand.get('ID') not in pageId_list:
                 continue
 
             if fileGrp:
diff --git a/ocrd_utils/ocrd_utils/str.py b/ocrd_utils/ocrd_utils/str.py
index 2944bb1d33..7211699f0c 100644
--- a/ocrd_utils/ocrd_utils/str.py
+++ b/ocrd_utils/ocrd_utils/str.py
@@ -195,10 +195,12 @@ def generate_range(start, end):
     Generate a list of strings by incrementing the number part of ``start`` until including ``end``.
     """
     ret = []
-    start_num, end_num = re.search(r'\d+', start), re.search(r'\d+', end)
-    if not (start_num and end_num):
-        raise ValueError("Unable to generate range %s .. %s, could not detect number part" % (start, end))
-    start_num, end_num = start_num.group(0), end_num.group(0)
+    try:
+        start_num, end_num = re.findall(r'\d+', start)[-1], re.findall(r'\d+', end)[-1]
+    except IndexError:
+        raise ValueError("Range '%s..%s': could not find numeric part" % (start, end))
+    if start_num == end_num:
+        raise ValueError("Range '%s..%s': evaluates to the same number")
     for i in range(int(start_num), int(end_num) + 1):
         ret.append(start.replace(start_num, str(i).zfill(len(start_num))))
     return ret
diff --git a/tests/model/test_ocrd_mets.py b/tests/model/test_ocrd_mets.py
index e91ab66142..f8ea1c4fe9 100644
--- a/tests/model/test_ocrd_mets.py
+++ b/tests/model/test_ocrd_mets.py
@@ -74,7 +74,8 @@ def test_find_all_files(sbb_sample_01):
     assert len(sbb_sample_01.find_all_files(url='OCR-D-IMG/FILE_0005_IMAGE.tif')) == 1, '1 xlink:href="OCR-D-IMG/FILE_0005_IMAGE.tif"'
     assert len(sbb_sample_01.find_all_files(pageId='PHYS_0001..PHYS_0005')) == 35, '35 files for page "PHYS_0001..PHYS_0005"'
     assert len(sbb_sample_01.find_all_files(pageId='//PHYS_000(1|2)')) == 34, '34 files in PHYS_001 and PHYS_0002'
-
+    assert len(sbb_sample_01.find_all_files(pageId='//PHYS_0001,//PHYS_0005')) == 18, '18 files in PHYS_001 and PHYS_0005 (two regexes)'
+    assert len(sbb_sample_01.find_all_files(pageId='//PHYS_0005,PHYS_0001..PHYS_0002')) == 35, '35 files in //PHYS_0005,PHYS_0001..PHYS_0002'
 
 def test_find_all_files_local_only(sbb_sample_01):
     assert len(sbb_sample_01.find_all_files(pageId='PHYS_0001',
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 467724bd40..b04a9a2722 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -315,8 +315,10 @@ def test_make_file_id_744(self):
 
     def test_generate_range(self):
         assert generate_range('PHYS_0001', 'PHYS_0005') == ['PHYS_0001', 'PHYS_0002', 'PHYS_0003', 'PHYS_0004', 'PHYS_0005']
-        with self.assertRaisesRegex(ValueError, 'Unable to generate range'):
+        with self.assertRaisesRegex(ValueError, 'could not find numeric part'):
             generate_range('NONUMBER', 'ALSO_NONUMBER')
+        with self.assertRaisesRegex(ValueError, 'evaluates to the same number'):
+            generate_range('PHYS_0001_123', 'PHYS_0010_123')
 
     def test_safe_filename(self):
         assert safe_filename('Hello world,!') == 'Hello_world_'