diff --git a/rtchallenge/src/materials.rs b/rtchallenge/src/materials.rs
index efb21d8..ee436d9 100644
--- a/rtchallenge/src/materials.rs
+++ b/rtchallenge/src/materials.rs
@@ -119,7 +119,7 @@ pub fn lighting(
         // from the eye.
         let reflectv = reflect(-lightv, normalv);
         let reflect_dot_eye = dot(reflectv, eyev);
-        let specular = if reflect_dot_eye < 0. {
+        let specular = if reflect_dot_eye <= 0. {
             BLACK
         } else {
             // Compute the specular contribution.