diff --git a/core/includes/form.inc b/core/includes/form.inc
index 1bab88c..aaf27be 100644
--- a/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -4181,7 +4181,7 @@ function form_validate_color(&$element, &$form_state) {
   else {
     // Try to parse the value and normalize it.
     try {
-      form_set_value($element, Color::rgb2hex(Color::hex2rgb($value)), $form_state);
+      form_set_value($element, Color::rgbToHex(Color::hexToRGB($value)), $form_state);
     }
     catch (\InvalidArgumentException $e) {
       form_error($element, t('%name must be a valid color.', array('%name' => empty($element['#title']) ? $element['#parents'][0] : $element['#title'])));