diff --git a/pil_utils/build_image.py b/pil_utils/build_image.py
index a0545b3..c2377e0 100644
--- a/pil_utils/build_image.py
+++ b/pil_utils/build_image.py
@@ -335,7 +335,7 @@ def color_mask(self, color: ColorType) -> "BuildImage":
         rgb_sum = sum(color)
         for i in range(h):
             for j in range(w):
-                value = img_gray[i, j]
+                value = int(img_gray[i, j])
                 new_color = (
                     [
                         int(value * r / rgb_sum),
diff --git a/pyproject.toml b/pyproject.toml
index 565b553..a4c4501 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pil-utils"
-version = "0.1.11"
+version = "0.1.12"
 description = "A simple PIL wrapper and text-to-image tool"
 authors = ["meetwq <meetwq@gmail.com>"]
 license = "MIT"