diff --git a/src/python/python/ad/integrators/common.py b/src/python/python/ad/integrators/common.py
index 195e6b807..65067b7a1 100644
--- a/src/python/python/ad/integrators/common.py
+++ b/src/python/python/ad/integrators/common.py
@@ -1138,9 +1138,12 @@ def render_primarily_visible_silhouette(self,
         block = film.create_block(normalize=True)
         block.set_coalesce(block.coalesce() and spp >= 4)
         block.put(
-            pos=sensor_ds.uv,
+            pos=sensor_ds.uv + mi.ScalarPoint2f(block.offset()),
             wavelengths=wavelengths,
-            value=derivative * dr.rcp(mi.ScalarFloat(spp)),
+            # Boundary samples are not tied to pixels: normalize by their
+            # count and the pixel area, not by `spp`
+            value=derivative * (dr.prod(film.crop_size()) /
+                                mi.ScalarFloat(sampler.wavefront_size())),
             weight=0,
             alpha=1,
             active=active
@@ -1246,14 +1249,16 @@ def render_indirect_silhouette(self,
                 scene, sensor, sample, sampler, preprocess=False)
             active = dr.any(value != 0)
 
-            # Account for the guiding sampling density and spp
-            value *= rcp_pdf_guiding * dr.rcp(spp)
+            # Account for the guiding density, the sample count and the
+            # pixel area
+            value *= rcp_pdf_guiding * (dr.prod(film.crop_size()) /
+                                        mi.ScalarFloat(sampler.wavefront_size()))
 
             # Splat the result to the film
             block = film.create_block(normalize=True)
             block.set_coalesce(block.coalesce() and spp >= 4)
             block.put(
-                pos=sensor_uv,
+                pos=sensor_uv + mi.ScalarPoint2f(block.offset()),
                 wavelengths=wavelengths,
                 value=value,
                 weight=0,
diff --git a/src/python/python/ad/projective.py b/src/python/python/ad/projective.py
index 4c8b6fede..2e312082c 100644
--- a/src/python/python/ad/projective.py
+++ b/src/python/python/ad/projective.py
@@ -175,7 +175,17 @@ def eval_primary_silhouette_radiance_difference(self,
             it = dr.zeros(mi.Interaction3f)
             it.p = ss.p
             ds, _ = sensor.sample_direction(it, mi.Point2f(0), active)
-            visible &= ds.pdf != 0
+            film = sensor.film()
+            if film.sample_border():
+                # The filter reaches past the crop window, so points just
+                # outside of it still contribute
+                border = film.rfilter().border_size()
+                size = mi.ScalarVector2f(film.crop_size())
+                in_front = (to_world.inverse() @ ss.p).z > 0
+                visible &= in_front & dr.all((ds.uv >= -border) &
+                                             (ds.uv <= size + border))
+            else:
+                visible &= ds.pdf != 0
 
             # Sample wavelengths
             wavelength_sample = 0