diff --git a/is_themecore/src/Core/Smarty/SmartyHelperFunctions.php b/is_themecore/src/Core/Smarty/SmartyHelperFunctions.php
index ab209ff..a28ea5f 100644
--- a/is_themecore/src/Core/Smarty/SmartyHelperFunctions.php
+++ b/is_themecore/src/Core/Smarty/SmartyHelperFunctions.php
@@ -4,6 +4,7 @@ namespace Oksydan\Module\IsThemeCore\Core\Smarty;
 
 use Oksydan\Module\IsThemeCore\Core\Webp\WebpPictureGenerator;
 use Oksydan\Module\IsThemeCore\Form\Settings\WebpConfiguration;
+use PrestaShop\PrestaShop\Core\Util\ColorBrightnessCalculator;
 
 class SmartyHelperFunctions
 {
@@ -189,4 +190,9 @@ class SmartyHelperFunctions
 
         return $content;
     }
+     public static function isBright($hexColor)
+    {
+        $calculator = new ColorBrightnessCalculator();
+        return $calculator->isBright($hexColor);
+    }
 }
diff --git a/is_themecore/src/Hook/Smarty.php b/is_themecore/src/Hook/Smarty.php
index 368380b..7a9fc00 100644
--- a/is_themecore/src/Hook/Smarty.php
+++ b/is_themecore/src/Hook/Smarty.php
@@ -51,5 +51,10 @@ public function hookActionDispatcherBefore(): void
         } else {
             return;
         }
+         if (!isset($this->context->smarty->registered_plugins['modifier']['is_bright'])) {
+            $this->context->smarty->registerPlugin('modifier', 'is_bright', ['Oksydan\Module\IsThemeCore\Core\Smarty\SmartyHelperFunctions', 'isBright']);
+        } else {
+            return;
+        }
     }
 }