diff --git a/src/MD_STD_IN.php b/src/MD_STD_IN.php
index fe7b4e6..16b08b5 100644
--- a/src/MD_STD_IN.php
+++ b/src/MD_STD_IN.php
@@ -96,7 +96,7 @@ final class MD_STD_IN {
      */
     public static function sanitize_rgb_color(mixed $input):string {
 
-        if (($output = \filter_var($input, FILTER_UNSAFE_RAW, FILTER_FLAG_STRIP_LOW | FILTER_FLAG_STRIP_HIGH)) === false) {
+        if (empty($output = \filter_var($input, FILTER_UNSAFE_RAW, FILTER_FLAG_STRIP_LOW | FILTER_FLAG_STRIP_HIGH))) {
             throw new MDInvalidColorCode("Invalid color code provided: " . $output);
         }