diff --git a/bob/ip/binseg/engine/evaluator.py b/bob/ip/binseg/engine/evaluator.py
index c3124ef9c68b4c6e203a5d2e53adbf31b2d0cffc..d927c84cf758034eab3f20740208af77a1ed72b9 100644
--- a/bob/ip/binseg/engine/evaluator.py
+++ b/bob/ip/binseg/engine/evaluator.py
@@ -179,7 +179,9 @@ def _sample_analysis(
 
     if overlay:
         img = VF.to_pil_image(img)  # PIL Image
-        tp_pil_colored = PIL.Image.blend(img, tp_pil_colored, 0.4)
+        # using blend here, to fade original image being overlayed, or
+        # its brightness may obfuscate colors from the vessel map
+        tp_pil_colored = PIL.Image.blend(img, tp_pil_colored, 0.5)
 
     return tp_pil_colored