diff --git a/interface.go b/interface.go
index 479c3af..ab642ce 100644
--- a/interface.go
+++ b/interface.go
@@ -72,7 +72,7 @@ type TrianglesPosition interface {
 // Default value for a color is the white color.
 type TrianglesColor interface {
 	Triangles
-	Color(i int) color.Color
+	Color(i int) NRGBA
 }
 
 // TrianglesTexture specifies Triangles with Texture propery.