diff --git a/pdfminer/cmapdb.py b/pdfminer/cmapdb.py
index fdcc5de..a1cc53c 100644
--- a/pdfminer/cmapdb.py
+++ b/pdfminer/cmapdb.py
@@ -91,7 +91,7 @@ class CMap(CMapBase):
         return
 
     def decode(self, code):
-        logging.debug('decode: %r, %r' % (self, code))
+        logging.debug('decode: %r, %r', self, code)
         d = self.code2cid
         for i in six.iterbytes(code):
             if i in d:
@@ -141,7 +141,7 @@ class UnicodeMap(CMapBase):
         return '<UnicodeMap: %s>' % self.attrs.get('CMapName')
 
     def get_unichr(self, cid):
-        logging.debug('get_unichr: %r, %r' % (self, cid))
+        logging.debug('get_unichr: %r, %r', self, cid)
         return self.cid2unichr[cid]
 
     def dump(self, out=sys.stdout):
@@ -228,7 +228,7 @@ class CMapDB(object):
     @classmethod
     def _load_data(klass, name):
         filename = '%s.pickle.gz' % name
-        logging.info('loading: %r' % name)
+        logging.info('loading: %r', name)
         cmap_paths = (os.environ.get('CMAP_PATH', '/usr/share/pdfminer/'),
                       os.path.join(os.path.dirname(__file__), 'cmap'),)
         for directory in cmap_paths:
diff --git a/pdfminer/converter.py b/pdfminer/converter.py
index ccf1d2a..e93b055 100644
--- a/pdfminer/converter.py
+++ b/pdfminer/converter.py
@@ -117,7 +117,7 @@ class PDFLayoutAnalyzer(PDFTextDevice):
         return item.adv
 
     def handle_undefined_char(self, font, cid):
-        logging.info('undefined: %r, %r' % (font, cid))
+        logging.info('undefined: %r, %r', font, cid)
         return '(cid:%d)' % cid
 
     def receive_layout(self, ltpage):
diff --git a/pdfminer/pdfdocument.py b/pdfminer/pdfdocument.py
index a49ae0b..a63213a 100644
--- a/pdfminer/pdfdocument.py
+++ b/pdfminer/pdfdocument.py
@@ -127,7 +127,7 @@ class PDFXRef(PDFBaseXRef):
                 if use != b'n':
                     continue
                 self.offsets[objid] = (None, long(pos) if six.PY2 else int(pos), int(genno))
-        logging.info('xref objects: %r' % self.offsets)
+        logging.info('xref objects: %r', self.offsets)
         self.load_trailer(parser)
         return
 
@@ -142,7 +142,7 @@ class PDFXRef(PDFBaseXRef):
                 raise PDFNoValidXRef('Unexpected EOF - file corrupted')
             (_, dic) = x[0]
         self.trailer.update(dict_value(dic))
-        logging.debug('trailer=%r'%self.trailer)
+        logging.debug('trailer=%r', self.trailer)
         return
 
     def get_trailer(self):
@@ -177,7 +177,7 @@ class PDFXRefFallback(PDFXRef):
             if line.startswith(b'trailer'):
                 parser.seek(pos)
                 self.load_trailer(parser)
-                logging.info('trailer: %r' % self.get_trailer())
+                logging.info('trailer: %r', self.trailer)
                 break
             if six.PY3:
                 line=line.decode('latin-1') #default pdf encoding
@@ -244,9 +244,9 @@ class PDFXRefStream(PDFBaseXRef):
         self.data = stream.get_data()
         self.entlen = self.fl1+self.fl2+self.fl3
         self.trailer = stream.attrs
-        logging.info('xref stream: objid=%s, fields=%d,%d,%d' %
-                     (', '.join(map(repr, self.ranges)),
-                      self.fl1, self.fl2, self.fl3))
+        logging.info('xref stream: objid=%s, fields=%d,%d,%d',
+                     ', '.join(map(repr, self.ranges)),
+                      self.fl1, self.fl2, self.fl3)
         return
 
     def get_trailer(self):
@@ -655,7 +655,7 @@ class PDFDocument(object):
         assert objid != 0
         if not self.xrefs:
             raise PDFException('PDFDocument is not initialized')
-        logging.debug('getobj: objid=%r' % objid)
+        logging.debug('getobj: objid=%r', objid)
         if objid in self._cached_objs:
             (obj, genno) = self._cached_objs[objid]
         else:
@@ -680,7 +680,7 @@ class PDFDocument(object):
                     continue
             else:
                 raise PDFObjectNotFound(objid)
-            logging.debug('register: objid=%r: %r' % (objid, obj))
+            logging.debug('register: objid=%r: %r', objid, obj)
             if self.caching:
                 self._cached_objs[objid] = (obj, genno)
         return obj
@@ -753,14 +753,14 @@ class PDFDocument(object):
         prev = None
         for line in parser.revreadlines():
             line = line.strip()
-            logging.debug('find_xref: %r' % line)
+            logging.debug('find_xref: %r', line)
             if line == b'startxref':
                 break
             if line:
                 prev = line
         else:
             raise PDFNoValidXRef('Unexpected EOF')
-        logging.info('xref found: pos=%r' % prev)
+        logging.info('xref found: pos=%r', prev)
         return long(prev) if six.PY2 else int(prev)
 
     # read xref table
@@ -772,7 +772,7 @@ class PDFDocument(object):
             (pos, token) = parser.nexttoken()
         except PSEOF:
             raise PDFNoValidXRef('Unexpected EOF')
-        logging.info('read_xref_from: start=%d, token=%r' % (start, token))
+        logging.info('read_xref_from: start=%d, token=%r', start, token)
         if isinstance(token, int):
             # XRefStream: PDF-1.5
             parser.seek(pos)
@@ -786,7 +786,7 @@ class PDFDocument(object):
             xref.load(parser)
         xrefs.append(xref)
         trailer = xref.get_trailer()
-        logging.info('trailer: %r' % trailer)
+        logging.info('trailer: %r', trailer)
         if 'XRefStm' in trailer:
             pos = int_value(trailer['XRefStm'])
             self.read_xref_from(parser, pos, xrefs)
diff --git a/pdfminer/pdfinterp.py b/pdfminer/pdfinterp.py
index 5d73ca4..779c864 100644
--- a/pdfminer/pdfinterp.py
+++ b/pdfminer/pdfinterp.py
@@ -166,7 +166,7 @@ class PDFResourceManager(object):
         if objid and objid in self._cached_fonts:
             font = self._cached_fonts[objid]
         else:
-            logging.info('get_font: create: objid=%r, spec=%r' % (objid, spec))
+            logging.info('get_font: create: objid=%r, spec=%r', objid, spec)
             if STRICT:
                 if spec['Type'] is not LITERAL_FONT:
                     raise PDFFontError('Type is not /Font')
@@ -340,7 +340,7 @@ class PDFPageInterpreter(object):
             else:
                 return PREDEFINED_COLORSPACE.get(name)
         for (k, v) in six.iteritems(dict_value(resources)):
-            logging.debug('Resource: %r: %r' % (k, v))
+            logging.debug('Resource: %r: %r', k, v)
             if k == 'Font':
                 for (fontid, spec) in six.iteritems(dict_value(v)):
                     objid = None
@@ -796,7 +796,7 @@ class PDFPageInterpreter(object):
             if STRICT:
                 raise PDFInterpreterError('Undefined xobject id: %r' % xobjid)
             return
-        logging.info('Processing xobj: %r' % xobj)
+        logging.info('Processing xobj: %r', xobj)
         subtype = xobj.get('Subtype')
         if subtype is LITERAL_FORM and 'BBox' in xobj:
             interpreter = self.dup()
@@ -819,7 +819,7 @@ class PDFPageInterpreter(object):
         return
 
     def process_page(self, page):
-        logging.info('Processing page: %r' % page)
+        logging.info('Processing page: %r', page)
         (x0, y0, x1, y1) = page.mediabox
         if page.rotate == 90:
             ctm = (0, -1, 1, 0, -y0, x1)
@@ -838,8 +838,8 @@ class PDFPageInterpreter(object):
     #   Render the content streams.
     #   This method may be called recursively.
     def render_contents(self, resources, streams, ctm=MATRIX_IDENTITY):
-        logging.info('render_contents: resources=%r, streams=%r, ctm=%r' %
-                     (resources, streams, ctm))
+        logging.info('render_contents: resources=%r, streams=%r, ctm=%r',
+                     resources, streams, ctm)
         self.init_resources(resources)
         self.init_state(ctm)
         self.execute(list_value(streams))
@@ -864,11 +864,11 @@ class PDFPageInterpreter(object):
                     nargs = six.get_function_code(func).co_argcount-1
                     if nargs:
                         args = self.pop(nargs)
-                        logging.debug('exec: %s %r' % (name, args))
+                        logging.debug('exec: %s %r', name, args)
                         if len(args) == nargs:
                             func(*args)
                     else:
-                        logging.debug('exec: %s' % name)
+                        logging.debug('exec: %s', name)
                         func()
                 else:
                     if STRICT:
diff --git a/pdfminer/pdfpage.py b/pdfminer/pdfpage.py
index 5755229..25a351c 100644
--- a/pdfminer/pdfpage.py
+++ b/pdfminer/pdfpage.py
@@ -87,12 +87,12 @@ class PDFPage(object):
                 if k in klass.INHERITABLE_ATTRS and k not in tree:
                     tree[k] = v
             if tree.get('Type') is LITERAL_PAGES and 'Kids' in tree:
-                logging.info('Pages: Kids=%r' % tree['Kids'])
+                logging.info('Pages: Kids=%r', tree['Kids'])
                 for c in list_value(tree['Kids']):
                     for x in search(c, tree):
                         yield x
             elif tree.get('Type') is LITERAL_PAGE:
-                logging.info('Page: %r' % tree)
+                logging.info('Page: %r', tree)
                 yield (objid, tree)
         pages = False
         if 'Pages' in document.catalog:
diff --git a/pdfminer/pdfparser.py b/pdfminer/pdfparser.py
index 6daf1eb..7407ade 100644
--- a/pdfminer/pdfparser.py
+++ b/pdfminer/pdfparser.py
@@ -120,7 +120,7 @@ class PDFParser(PSStackParser):
                     data += line
             self.seek(pos+objlen)
             # XXX limit objlen not to exceed object boundary
-            logging.debug('Stream: pos=%d, objlen=%d, dic=%r, data=%r...' % (pos, objlen, dic, data[:10]))
+            logging.debug('Stream: pos=%d, objlen=%d, dic=%r, data=%r...', pos, objlen, dic, data[:10])
             obj = PDFStream(dic, data, self.doc.decipher)
             self.push((pos, obj))
 
diff --git a/pdfminer/pdftypes.py b/pdfminer/pdftypes.py
index 229c2be..64d84bb 100644
--- a/pdfminer/pdftypes.py
+++ b/pdfminer/pdftypes.py
@@ -162,7 +162,7 @@ def dict_value(x):
     if not isinstance(x, dict):
         if STRICT:
             import logging
-            logging.error('PDFTypeError : Dict required: %r' % x)
+            logging.error('PDFTypeError : Dict required: %r', x)
             raise PDFTypeError('Dict required: %r' % x)
         return {}
     return x
diff --git a/pdfminer/psparser.py b/pdfminer/psparser.py
index e9093fe..dbc7861 100644
--- a/pdfminer/psparser.py
+++ b/pdfminer/psparser.py
@@ -207,14 +207,14 @@ class PSBaseParser(object):
         if not pos:
             pos = self.bufpos+self.charpos
         self.fp.seek(pos)
-        logging.info('poll(%d): %r' % (pos, self.fp.read(n)))
+        logging.info('poll(%d): %r', pos, self.fp.read(n))
         self.fp.seek(pos0)
         return
 
     def seek(self, pos):
         """Seeks the parser to the given position.
         """
-        logging.debug('seek: %r' % pos)
+        logging.debug('seek: %r', pos)
         self.fp.seek(pos)
         # reset the status for nextline()
         self.bufpos = pos
@@ -264,7 +264,7 @@ class PSBaseParser(object):
             else:
                 linebuf += bytesindex(self.buf,self.charpos,-1)
                 self.charpos = len(self.buf)
-        logging.debug('nextline: %r, %r' % (linepos, linebuf))
+        logging.debug('nextline: %r, %r', linepos, linebuf)
         
         return (linepos, linebuf)
 
@@ -507,7 +507,7 @@ class PSBaseParser(object):
             self.fillbuf()
             self.charpos = self._parse1(self.buf, self.charpos)
         token = self._tokens.pop(0)
-        logging.debug('nexttoken: (%r:%r)' % token)
+        logging.debug('nexttoken: %r', token)
         return token
 
 
@@ -548,7 +548,7 @@ class PSStackParser(PSBaseParser):
 
     def add_results(self, *objs):
         try:
-            logging.debug('add_results: %s' % repr(objs))
+            logging.debug('add_results: %r', objs)
         except:
             logging.debug('add_results: (unprintable object)')
         self.results.extend(objs)
@@ -557,7 +557,7 @@ class PSStackParser(PSBaseParser):
     def start_type(self, pos, type):
         self.context.append((pos, self.curtype, self.curstack))
         (self.curtype, self.curstack) = (type, [])
-        logging.debug('start_type: pos=%r, type=%r' % (pos, type))
+        logging.debug('start_type: pos=%r, type=%r', pos, type)
         return
 
     def end_type(self, type):
@@ -565,7 +565,7 @@ class PSStackParser(PSBaseParser):
             raise PSTypeError('Type mismatch: %r != %r' % (self.curtype, type))
         objs = [obj for (_, obj) in self.curstack]
         (pos, self.curtype, self.curstack) = self.context.pop()
-        logging.debug('end_type: pos=%r, type=%r, objs=%r' % (pos, type, objs))
+        logging.debug('end_type: pos=%r, type=%r, objs=%r', pos, type, objs)
         return (pos, objs)
 
     def do_keyword(self, pos, token):
@@ -619,10 +619,10 @@ class PSStackParser(PSBaseParser):
                     if STRICT:
                         raise
             elif isinstance(token,PSKeyword):
-                logging.debug('do_keyword: pos=%r, token=%r, stack=%r' % (pos, token, self.curstack))
+                logging.debug('do_keyword: pos=%r, token=%r, stack=%r', pos, token, self.curstack)
                 self.do_keyword(pos, token)
             else:
-                logging.error('unknown token: pos=%r, token=%r, stack=%r' % (pos, token, self.curstack))
+                logging.error('unknown token: pos=%r, token=%r, stack=%r', pos, token, self.curstack)
                 self.do_keyword(pos, token)
                 raise
             if self.context:
@@ -631,7 +631,7 @@ class PSStackParser(PSBaseParser):
                 self.flush()
         obj = self.results.pop(0)
         try:
-            logging.debug('nextobject: %s' % repr(obj))
+            logging.debug('nextobject: %r', obj)
         except:
             logging.debug('nextobject: (unprintable object)')
         return obj