diff --git a/data/lua/wml-tags.lua b/data/lua/wml-tags.lua
index 53d15b710aa..d1845fd75eb 100644
--- a/data/lua/wml-tags.lua
+++ b/data/lua/wml-tags.lua
@@ -715,7 +715,7 @@ function wml_actions.scroll(cfg)
 end
 
 function wml_actions.color_adjust(cfg)
-	wesnoth.interface.color_adjust(cfg.red, cfg.green, cfg.blue)
+	wesnoth.interface.color_adjust(cfg.red or 0, cfg.green or 0, cfg.blue or 0)
 end
 
 function wml_actions.end_turn(cfg)