diff --git a/Tests/test_file_eps.py b/Tests/test_file_eps.py
index d01884f96c5..1c21aa8ca67 100644
--- a/Tests/test_file_eps.py
+++ b/Tests/test_file_eps.py
@@ -336,9 +336,7 @@ def test_readline_psfile(tmp_path: Path) -> None:
     strings = ["something", "else", "baz", "bif"]
 
     def _test_readline(t: EpsImagePlugin.PSFile, ending: str) -> None:
-        ending = "Failure with line ending: %s" % (
-            "".join("%s" % ord(s) for s in ending)
-        )
+        ending = f"Failure with line ending: {''.join(str(ord(s)) for s in ending)}"
         assert t.readline().strip("\r\n") == "something", ending
         assert t.readline().strip("\r\n") == "else", ending
         assert t.readline().strip("\r\n") == "baz", ending
diff --git a/Tests/test_image_access.py b/Tests/test_image_access.py
index 02c75073add..e55a4d9c1fb 100644
--- a/Tests/test_image_access.py
+++ b/Tests/test_image_access.py
@@ -409,13 +409,14 @@ def test_embeddable(self) -> None:
         from setuptools.command import build_ext
 
         with open("embed_pil.c", "w", encoding="utf-8") as fh:
+            home = sys.prefix.replace("\\", "\\\\")
             fh.write(
-                """
+                f"""
 #include "Python.h"
 
 int main(int argc, char* argv[])
-{
-    char *home = "%s";
+{{
+    char *home = "{home}";
     wchar_t *whome = Py_DecodeLocale(home, NULL);
     Py_SetPythonHome(whome);
 
@@ -430,9 +431,8 @@ def test_embeddable(self) -> None:
     PyMem_RawFree(whome);
 
     return 0;
-}
+}}
         """
-                % sys.prefix.replace("\\", "\\\\")
             )
 
         compiler = getattr(build_ext, "new_compiler")()
diff --git a/selftest.py b/selftest.py
index 661abcddb74..9e049367edc 100755
--- a/selftest.py
+++ b/selftest.py
@@ -165,9 +165,9 @@ def testimage() -> None:
     print("Running selftest:")
     status = doctest.testmod(sys.modules[__name__])
     if status[0]:
-        print("*** %s tests of %d failed." % status)
+        print(f"*** {status[0]} tests of {status[1]} failed.")
         exit_status = 1
     else:
-        print("--- %s tests passed." % status[1])
+        print(f"--- {status[1]} tests passed.")
 
     sys.exit(exit_status)
diff --git a/src/PIL/IptcImagePlugin.py b/src/PIL/IptcImagePlugin.py
index 4096094348a..73df83bfb31 100644
--- a/src/PIL/IptcImagePlugin.py
+++ b/src/PIL/IptcImagePlugin.py
@@ -57,7 +57,7 @@ def dump(c: Sequence[int | bytes]) -> None:
     """.. deprecated:: 10.2.0"""
     deprecate("IptcImagePlugin.dump", 12)
     for i in c:
-        print("%02x" % _i8(i), end=" ")
+        print(f"{_i8(i):02x}", end=" ")
     print()
 
 
diff --git a/src/PIL/PdfParser.py b/src/PIL/PdfParser.py
index c1ed7879741..c43f2da7baa 100644
--- a/src/PIL/PdfParser.py
+++ b/src/PIL/PdfParser.py
@@ -823,11 +823,10 @@ def get_value(cls, data, offset, expect_indirect=None, max_nesting=-1):
             m = cls.re_stream_start.match(data, offset)
             if m:
                 try:
-                    stream_len = int(result[b"Length"])
-                except (TypeError, KeyError, ValueError) as e:
-                    msg = "bad or missing Length in stream dict (%r)" % result.get(
-                        b"Length", None
-                    )
+                    stream_len_str = result.get(b"Length")
+                    stream_len = int(stream_len_str)
+                except (TypeError, ValueError) as e:
+                    msg = f"bad or missing Length in stream dict ({stream_len_str})"
                     raise PdfFormatError(msg) from e
                 stream_data = data[m.end() : m.end() + stream_len]
                 m = cls.re_stream_end.match(data, m.end() + stream_len)