diff --git a/crates/pptx/src/write/dml.rs b/crates/pptx/src/write/dml.rs
index 1af1d9627..3705cc93a 100644
--- a/crates/pptx/src/write/dml.rs
+++ b/crates/pptx/src/write/dml.rs
@@ -357,13 +357,16 @@ pub fn effects(w: &mut W, fx: &Effects) {
                 .a("endA", pct(r.end_alpha.clamp(0.0, 1.0)))
                 .a("endPos", pct(r.end_pos.clamp(0.0, 1.0)))
                 .a("dist", emu(r.dist).max(0))
-                .o("stPos", r.st_pos)
-                .o("dir", r.dir)
-                .o("fadeDir", r.fade_dir)
+                // Kept from a file as read: held to the schema's ranges so a stray value can't
+                // make PowerPoint repair the file (ST_PositiveFixedAngle, ST_FixedAngle,
+                // ST_PositiveFixedPercentage).
+                .o("stPos", r.st_pos.map(|v| v.clamp(0, 100_000)))
+                .o("dir", r.dir.map(|v| v.rem_euclid(21_600_000)))
+                .o("fadeDir", r.fade_dir.map(|v| v.rem_euclid(21_600_000)))
                 .o("sx", r.sx)
                 .o("sy", r.sy)
-                .o("kx", r.kx)
-                .o("ky", r.ky)
+                .o("kx", r.kx.map(|v| v.clamp(-5_399_999, 5_399_999)))
+                .o("ky", r.ky.map(|v| v.clamp(-5_399_999, 5_399_999)))
                 .o("algn", r.align.as_deref())
                 .b("rotWithShape", r.rotate_with_shape),
         );
diff --git a/crates/pptx/tests/it/roundtrip.rs b/crates/pptx/tests/it/roundtrip.rs
index 1ed97f546..36330460b 100644
--- a/crates/pptx/tests/it/roundtrip.rs
+++ b/crates/pptx/tests/it/roundtrip.rs
@@ -2094,3 +2094,26 @@ fn default_durations_match_powerpoint() {
         assert_eq!(a.4, ms, "{effect}");
     }
 }
+
+#[test]
+fn reflection_angles_and_skews_out_of_range_are_written_inside_the_schema() {
+    let mut p = Presentation::default();
+    let mut slide = new_slide(&mut p, "Reflection ranges");
+    let mut s = shape(&mut p, "Reflected", 10.0, 10.0, 200.0, 80.0);
+    s.effects = Some(deckcraft_model::style::Effects {
+        reflection: Some(deckcraft_model::style::Reflection {
+            st_pos: Some(150_000),
+            dir: Some(-5),
+            fade_dir: Some(21_600_000),
+            kx: Some(9_000_000),
+            ky: Some(-9_000_000),
+            ..Default::default()
+        }),
+        ..Default::default()
+    });
+    slide.shapes.push(s);
+    p.slides.push(Arc::new(slide));
+
+    let r = round(&p).slides.last().and_then(|sl| by_name(sl, "Reflected").effects.clone()).and_then(|fx| fx.reflection).expect("reflection");
+    assert_eq!((r.st_pos, r.dir, r.fade_dir, r.kx, r.ky), (Some(100_000), Some(21_599_995), Some(0), Some(5_399_999), Some(-5_399_999)));
+}