diff --git a/utilities/mogrify.1.in b/utilities/mogrify.1.in
index 248f5b6..00af63e 100644
--- a/utilities/mogrify.1.in
+++ b/utilities/mogrify.1.in
@@ -133,6 +133,7 @@
   \-border geometry     surround image with a border of color
   \-brightness-contrast geometry
                        improve brightness / contrast of the image
+  \-canny geometry      detect edges in the image
   \-charcoal radius     simulate a charcoal drawing
   \-chop geometry       remove pixels from the image interior
   \-clamp               keep pixel values in range (0-QuantumRange)