diff -r db8bdbb34e03 -r 3edb3c857995 hedgewars/uLandObjects.pas
--- a/hedgewars/uLandObjects.pas	Sun Nov 06 12:40:35 2011 -0500
+++ b/hedgewars/uLandObjects.pas	Sun Nov 06 13:00:25 2011 -0500
@@ -445,6 +445,14 @@
         c2.g:= StrToInt(Trim(Copy(s, 1, Pred(i))));
         Delete(s, 1, i);
         c2.b:= StrToInt(Trim(s));
+        if cGrayScale then
+            begin
+            t:= round(SkyColor.r * RGB_LUMINANCE_RED + SkyColor.g * RGB_LUMINANCE_GREEN + SkyColor.b * RGB_LUMINANCE_BLUE);
+            if t > 255 then t:= 255;
+            c2.r:= t;
+            c2.g:= t;
+            c2.b:= t
+            end;
         cExplosionBorderColor:= c2.value or AMask;
         end
     else if key = 'water-top' then