diff --git a/giskard_vision/core/dataloaders/base.py b/giskard_vision/core/dataloaders/base.py
index 99bf22b6..f581b104 100644
--- a/giskard_vision/core/dataloaders/base.py
+++ b/giskard_vision/core/dataloaders/base.py
@@ -145,7 +145,11 @@ def get_meta(self, idx: int) -> Optional[TypesBase.meta]:
             Optional[TypesBase.meta]: Meta information for the given index.
         """
         img = self.get_image(idx)
-        gray_img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
+        if img.dtype != np.uint8:
+            # Normalize image to 0-255 range with uint8
+            img = (img * 255 % 255).astype(np.uint8)
+
+        gray_img = cv2.cvtColor(img, cv2.COLOR_RGB2GRAY)
         size = get_image_size(img)
         nb_channels = get_image_channel_number(img)
         avg_color = np.mean(img, axis=(0, 1))
diff --git a/giskard_vision/core/dataloaders/meta.py b/giskard_vision/core/dataloaders/meta.py
index dfabe672..93c06c14 100644
--- a/giskard_vision/core/dataloaders/meta.py
+++ b/giskard_vision/core/dataloaders/meta.py
@@ -219,7 +219,7 @@ def get_brightness(image: np.ndarray) -> float:
     Returns:
         float: The image brightness normalized to 1.
     """
-    hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)
+    hsv = cv2.cvtColor(image, cv2.COLOR_RGB2HSV)
     return np.mean(hsv[:, :, 2]) / 255