diff --git a/drv_X11.c b/drv_X11.c
index 939909e..f98e1fc 100644
--- a/drv_X11.c
+++ b/drv_X11.c
@@ -427,7 +427,7 @@ static int drv_X11_start(const char *section)
     XClearWindow(dp, w);
 
     /* set brightness (after first background painting) */
-    if (cfg_number(section, "Brightness", 0, 0, 255, &i) > 0) {
+    if (cfg_number(section, "Brightness", 255, 0, 255, &i) > 0) {
 	drv_X11_brightness(i);
     }