diff --git a/io_mesh_uv_layout/__init__.py b/io_mesh_uv_layout/__init__.py
index ad20a7a14efc40178ddf26c7de0eafbbfdf65a75..85d55b28703503af396a481a4f0f07381fe7df67 100644
--- a/io_mesh_uv_layout/__init__.py
+++ b/io_mesh_uv_layout/__init__.py
@@ -212,7 +212,7 @@ class ExportUVLayout(bpy.types.Operator):
         if polygon.material_index < len(mesh.materials):
             material = mesh.materials[polygon.material_index]
             if material is not None:
-                return tuple(material.diffuse_color)
+                return tuple(material.diffuse_color)[:3]
         return default
 
     def get_exporter(self):