diff --git a/lib/matplotlib/_type1font.py b/lib/matplotlib/_type1font.py
index b4ee5edb233c..c7b73f9c0c7e 100644
--- a/lib/matplotlib/_type1font.py
+++ b/lib/matplotlib/_type1font.py
@@ -866,17 +866,16 @@ def subset(self, characters, name_prefix):
         encoding = {code: glyph
                     for code, glyph in self.prop['Encoding'].items()
                     if code in characters}
-        encoding[0] = '.notdef'
         # todo and done include strings (glyph names)
-        todo = set(encoding.values())
+        todo = {'.notdef', *encoding.values()}
         done = set()
         seen_subrs = {0, 1, 2, 3}
         while todo:
             glyph = todo.pop()
             called_glyphs, called_subrs = _CharstringSimulator(self).run(glyph)
+            done.add(glyph)
             todo.update(called_glyphs - done)
             seen_subrs.update(called_subrs)
-            done.add(glyph)
 
         charstrings = self._subset_charstrings(done)
         subrs = self._subset_subrs(seen_subrs)
@@ -949,7 +948,8 @@ def _charstring_tokens(data):
     def _postscript_encoding(self, encoding):
         """Return a PostScript encoding array for the encoding."""
         return '\n'.join([
-            '/Encoding 256 array\n0 1 255 { 1 index exch /.notdef put} for',
+            '/Encoding 256 array',
+            '0 1 255 { 1 index exch /.notdef put} for',
             *(
                 f'dup {i} /{glyph} put'
                 for i, glyph in sorted(encoding.items())
diff --git a/lib/matplotlib/tests/baseline_images/test_usetex/test_usetex.pdf b/lib/matplotlib/tests/baseline_images/test_usetex/test_usetex.pdf
index f2ebbeb528cc..bce9d583d4d4 100644
Binary files a/lib/matplotlib/tests/baseline_images/test_usetex/test_usetex.pdf and b/lib/matplotlib/tests/baseline_images/test_usetex/test_usetex.pdf differ
diff --git a/lib/matplotlib/tests/baseline_images/test_usetex/test_usetex.png b/lib/matplotlib/tests/baseline_images/test_usetex/test_usetex.png
index e4a62a1c87ae..9f9d21b22528 100644
Binary files a/lib/matplotlib/tests/baseline_images/test_usetex/test_usetex.png and b/lib/matplotlib/tests/baseline_images/test_usetex/test_usetex.png differ
diff --git a/lib/matplotlib/tests/test_usetex.py b/lib/matplotlib/tests/test_usetex.py
index 87277f152789..6d7506055ce5 100644
--- a/lib/matplotlib/tests/test_usetex.py
+++ b/lib/matplotlib/tests/test_usetex.py
@@ -26,10 +26,11 @@ def test_usetex():
     kwargs = {"verticalalignment": "baseline", "size": 24,
               "bbox": dict(pad=0, edgecolor="k", facecolor="none")}
     ax.text(0.2, 0.7,
-            # the \LaTeX macro exercises character sizing and placement,
+            # The \LaTeX macro exercises character sizing and placement,
             # \left[ ... \right\} draw some variable-height characters,
-            # \sqrt and \frac draw horizontal rules, \mathrm changes the font
-            r'\LaTeX\ $\left[\int\limits_e^{2e}'
+            # \sqrt and \frac draw horizontal rules, \mathrm changes the font,
+            # the minus sign hits character code 0 in the Type 1 font that LaTeX uses.
+            r'\LaTeX\ $\left[\int\limits_e^{-2e}'
             r'\sqrt\frac{\log^3 x}{x}\,\mathrm{d}x \right\}$',
             **kwargs)
     ax.text(0.2, 0.3, "lg", **kwargs)