diff --git a/Tests/images/1.eps b/Tests/images/1.eps
new file mode 100644
index 00000000000..727dc9b7f04
Binary files /dev/null and b/Tests/images/1.eps differ
diff --git a/Tests/test_file_eps.py b/Tests/test_file_eps.py
index 1790f4f7701..766c5064920 100644
--- a/Tests/test_file_eps.py
+++ b/Tests/test_file_eps.py
@@ -146,6 +146,11 @@ def test_bytesio_object():
         assert_image_similar(img, image1_scale1_compare, 5)
 
 
+def test_1_mode():
+    with Image.open("Tests/images/1.eps") as im:
+        assert im.mode == "1"
+
+
 def test_image_mode_not_supported(tmp_path):
     im = hopper("RGBA")
     tmpfile = str(tmp_path / "temp.eps")
diff --git a/src/PIL/EpsImagePlugin.py b/src/PIL/EpsImagePlugin.py
index 3b782d6b353..0e434c5c0ea 100644
--- a/src/PIL/EpsImagePlugin.py
+++ b/src/PIL/EpsImagePlugin.py
@@ -288,11 +288,14 @@ def _open(self):
                 # Encoded bitmapped image.
                 x, y, bi, mo = s[11:].split(None, 7)[:4]
 
-                if int(bi) != 8:
-                    break
-                try:
-                    self.mode = self.mode_map[int(mo)]
-                except ValueError:
+                if int(bi) == 1:
+                    self.mode = "1"
+                elif int(bi) == 8:
+                    try:
+                        self.mode = self.mode_map[int(mo)]
+                    except ValueError:
+                        break
+                else:
                     break
 
                 self._size = int(x), int(y)