diff --git a/source/paint/detail/image_png.hpp b/source/paint/detail/image_png.hpp
index 9e01e8c6..30ba18e5 100644
--- a/source/paint/detail/image_png.hpp
+++ b/source/paint/detail/image_png.hpp
@@ -121,7 +121,7 @@ namespace nana
 				delete[] row_ptrs;
 			}
 		public:
-			bool open(const experimental::filesystem::path& png_file) override
+			bool open(const std::experimental::filesystem::path& png_file) override
 			{
 				auto fp = ::fopen(to_osmbstr(to_utf8(png_file.native())).c_str(), "rb");
 				if(nullptr == fp) return false;