diff --git a/src/rcfile.c b/src/rcfile.c
index f52bc45c..062fba55 100644
--- a/src/rcfile.c
+++ b/src/rcfile.c
@@ -991,10 +991,11 @@ void parse_includes(char *ptr)
 }
 
 /* Return the index of the color that is closest to the given RGB levels,
- * assuming that the terminal uses the 6x6x6 color cube of xterm-256color. */
+ * assuming that the terminal uses the 6x6x6 color cube of xterm-256color.
+ * When red == green == blue, return an index in the xterm gray scale. */
 short closest_index_color(short red, short green, short blue)
 {
-	/* Translation table, from 16 intended levels to 6 available levels. */
+	/* Translation table, from 16 intended color levels to 6 available levels. */
 	static const short level[] = { 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5 };
 
 	/* Translation table, from 14 intended gray levels to 24 available levels. */
@@ -1002,7 +1003,7 @@ short closest_index_color(short red, short green, short blue)
 
 	if (COLORS != 256)
 		return THE_DEFAULT;
-	else if (red == green && red == blue && red > 0 && red < 0xF)
+	else if (red == green && green == blue && 0 < red && red < 0xF)
 		return 232 + gray[red - 1];
 	else
 		return (36 * level[red] + 6 * level[green] + level[blue] + 16);