diff --git a/app/assets/javascripts/supplier/app/services/css-object.js.coffee b/app/assets/javascripts/supplier/app/services/css-object.js.coffee
index dfb271a9..a65aecca 100644
--- a/app/assets/javascripts/supplier/app/services/css-object.js.coffee
+++ b/app/assets/javascripts/supplier/app/services/css-object.js.coffee
@@ -19,7 +19,7 @@ App.CssObject.reopenClass
     [r, g, b]
 
   isColorDark: (rgb_hex)->
-    return false unless rbg_hex.match /#[0-9a-zA-Z]{6}/
+    return false unless rgb_hex and rbg_hex.match /#[0-9a-zA-Z]{6}/
     [r, g, b] = @rgb_to_numeric(rgb_hex)
     luma = 0.2126 * r + 0.7152 * g + 0.0722 * b # per ITU-R BT.709
     luma < 40