diff --git a/microqa/engine.py b/microqa/engine.py
index 2a285ef..2dae341 100644
--- a/microqa/engine.py
+++ b/microqa/engine.py
@@ -157,7 +157,9 @@ def analyze_sharpness(im: Image.Image) -> float:
     # results across documents. We've had much more luck with a direct gradient
     # computation based on https://stackoverflow.com/a/26014796.
     grad_y, grad_x = np.gradient(np.asarray(im))
-    return float(np.clip(np.quantile(np.sqrt(grad_x**2 + grad_y**2), 0.99) / 255, 0, 1))
+    return float(
+        np.clip(np.quantile(np.sqrt(grad_x**2 + grad_y**2), 0.9999) / 255, 0, 1)
+    )
 
 
 def compute_ocr(