diff --git a/python/pcb.py b/python/pcb.py
index 6fabb9542546dfeb0bcc0e73982a4cf12bf77507..86b815ddf76d46a44fb6f01502b6e283aba36694 100755
--- a/python/pcb.py
+++ b/python/pcb.py
@@ -25,6 +25,7 @@ output = "top, labels, holes, and exterior"
 #output = "top, bottom, labels, holes, and exterior"
 #output = "top traces"
 #output = "top traces and exterior"
+#output = "bottom traces"
 #output = "bottom traces reversed"
 #output = "bottom traces reversed and exterior"
 #output = "holes"
@@ -8298,6 +8299,9 @@ elif (output == "top traces"):
 elif (output == "top traces and exterior"):
    outputs["function"] = color(White,add(pcb.board,pcb.exterior))
    outputs["layers"] = [zt]
+elif (output == "bottom traces"):
+   outputs["function"] = color(White,pcb.board)
+   outputs["layers"] = [zb]
 elif (output == "bottom traces reversed"):
    outputs["function"] = color(White,
       reflect_x(pcb.board,2*x+width))