diff --git a/node_board/main.cpp b/node_board/main.cpp
index 2832f8031503f4f10f59d63cbcb2f8759f63f2fb..15018e220cd7c3d977c33666bf23cb454f64a7d3 100644
--- a/node_board/main.cpp
+++ b/node_board/main.cpp
@@ -19,7 +19,8 @@ public:
     {
         png_writer_.allocate(width_px_ + 4 * min_cut_thickness_px_,
                              height_px_ + 4 * min_cut_thickness_px_);
-        png_writer_.set_all_pixels_black();
+        png_writer_.set_all_pixels(255);
+        draw_int_rectangle(0, width_px_, 0, height_px_, 0);
     }
 
     int32_t to_px(double x) {