diff --git a/ChangeLog b/ChangeLog
index 11af21019a..a62220d36d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2004-04-03  Sven Neumann  <sven@gimp.org>
+
+	* plug-ins/Lighting/lighting_main.c
+	* plug-ins/Lighting/lighting_shade.c: applied the first of two
+	patches attached to bug #138788 by William Skaggs.
+
 2004-04-02  Simon Budig  <simon@gimp.org>
 
 	* plug-ins/common/whirlpinch.c: set a proper pixelfetcher 
diff --git a/plug-ins/Lighting/lighting_main.c b/plug-ins/Lighting/lighting_main.c
index 92806197cd..054b601ded 100644
--- a/plug-ins/Lighting/lighting_main.c
+++ b/plug-ins/Lighting/lighting_main.c
@@ -105,7 +105,7 @@ check_drawables (void)
 
   if (mapvals.bump_mapped)
     {
-      if (!gimp_drawable_is_gray (mapvals.bumpmap_id) ||
+      if (gimp_drawable_is_indexed (mapvals.bumpmap_id) ||
 	  (gimp_drawable_width (mapvals.drawable_id) !=
 	   gimp_drawable_width (mapvals.bumpmap_id)) ||
 	  (gimp_drawable_height (mapvals.drawable_id) !=
diff --git a/plug-ins/Lighting/lighting_shade.c b/plug-ins/Lighting/lighting_shade.c
index 58c7d6d767..3460ee3695 100644
--- a/plug-ins/Lighting/lighting_shade.c
+++ b/plug-ins/Lighting/lighting_shade.c
@@ -35,7 +35,7 @@ phong_shade (GimpVector3 *position,
 {
   GimpRGB       ambient_color, diffuse_color, specular_color;
   gdouble      nl, rv, dist;
-  GimpVector3  l, nn, v, n;
+  GimpVector3  l, v, n, lnormal, h;
 
   /* Compute ambient intensity */
   /* ========================= */
@@ -59,6 +59,12 @@ phong_shade (GimpVector3 *position,
 
   nl = 2.0 * gimp_vector3_inner_product (&n, &l);
 
+  lnormal.x = l.x;
+  lnormal.y = l.y;
+  lnormal.z = l.z;
+
+  gimp_vector3_normalize (&lnormal);
+
   if (nl >= 0.0)
     {
       /* Compute (R*V)^alpha term of Phong's equation */
@@ -67,10 +73,12 @@ phong_shade (GimpVector3 *position,
       gimp_vector3_sub (&v, viewpoint, position);
       gimp_vector3_normalize (&v);
 
-      gimp_vector3_mul (&n, nl);
-      gimp_vector3_sub (&nn, &n, &l);
-      rv = gimp_vector3_inner_product (&nn, &v);
+      gimp_vector3_add (&h, &lnormal, &v);
+      gimp_vector3_normalize (&h);
+
+      rv = MAX (0., gimp_vector3_inner_product (&n, &h));
       rv = pow (rv, mapvals.material.highlight);
+      rv *= nl;
 
       /* Compute diffuse and specular intensity contribution */
       /* =================================================== */
@@ -279,8 +287,6 @@ precompute_normals (gint x1,
       bpp = gimp_drawable_bpp(mapvals.bumpmap_id);
     }
   
-  bpp = gimp_drawable_bpp(mapvals.bumpmap_id);
-
   gimp_pixel_rgn_get_row (&bump_region, bumprow, x1, y, x2 - x1);
 
   if (mapvals.bumpmaptype > 0)