diff --git a/dev/calibration_test.star b/dev/calibration_test.star
index e4c657d..ca5232c 100644
--- a/dev/calibration_test.star
+++ b/dev/calibration_test.star
@@ -30,7 +30,7 @@ ART_ZOOM_DURATION = 200
 def _art_widget(art_bytes, zoom_scale):
     art = render.Image(src = art_bytes, width = ART_SIZE, height = ART_SIZE)
     top_scale = max(zoom_scale, 1.0)
-    shift = (1.0 - top_scale) * (ART_SIZE / 2.0)
+    shift = (1.0 - top_scale) * (ART_SIZE / 2.0) / top_scale
     zoom = animation.Transformation(
         child = art,
         duration = ART_ZOOM_DURATION,
diff --git a/subwave_nowplaying.star b/subwave_nowplaying.star
index e2ccab3..2ddf611 100644
--- a/subwave_nowplaying.star
+++ b/subwave_nowplaying.star
@@ -230,14 +230,24 @@ def _art_widget(art_bytes, zoom_scale):
     # bottom and right than the top and left -- most of the animation's
     # duration is spent between keyframes, not sitting at the symmetric
     # rest state, so this read as a persistent bottom/right crop. Pairing
-    # Scale with a Translate that's a deterministic function of the same
-    # scale value (`shift`) re-centers the zoom so it crops evenly from
+    # Scale with a Translate re-centers the zoom so it crops evenly from
     # all sides instead -- verified against a calibration grid image.
-    # This is safe because scale never drops below 1.0 here: the
-    # black-border bug from an earlier version came from combining
+    #
+    # The naive "final pixel shift" formula, (1-s)*(ART_SIZE/2), looked
+    # right at a moderate zoom (1.4x) but pushed past the image's actual
+    # edge at a strong one (1.7x) -- a real, on-device black border in the
+    # bottom-right corner. That means Translate isn't applied in final
+    # output pixels here; empirically, dividing by `top_scale` keeps the
+    # crop inside the image's bounds at every zoom level this app offers
+    # (verified via the calibration tool at both 1.4x and 1.7x), at the
+    # cost of the *most* extreme (1.7x) zoom being very slightly
+    # off-center rather than perfectly centered -- a trade worth making
+    # since going outside the art's bounds is worse than a slight
+    # asymmetry. This is safe because scale never drops below 1.0 here:
+    # the black-border bug from an earlier version came from combining
     # Translate with scale *below* 1.0, not from Translate itself.
     top_scale = max(zoom_scale, 1.0)
-    shift = (1.0 - top_scale) * (ART_SIZE / 2.0)
+    shift = (1.0 - top_scale) * (ART_SIZE / 2.0) / top_scale
     zoom = animation.Transformation(
         child = art,
         duration = ART_ZOOM_DURATION,