diff --git a/python/pcb.py b/python/pcb.py
index bca093fdad93298606811bbb63f5a889bd75d72d..150d28808b1f6abad208775646a9685df700c5ea 100755
--- a/python/pcb.py
+++ b/python/pcb.py
@@ -32,7 +32,8 @@ output = "top, labels, holes, and exterior"
 #output = "interior"
 #output = "holes and interior"
 #output = "exterior"
-#output = "solder mask"
+#output = "top solder mask"
+#output = "bottom solder mask"
 
 ############################################################
 # import
@@ -9005,9 +9006,12 @@ elif (output == "holes and interior"):
    outputs["function"] = color(White,
       subtract(pcb.interior,pcb.holes))
    outputs["layers"] = [zb]
-elif (output == "solder mask"):
+elif (output == "top solder mask"):
    outputs["function"] = color(White,pcb.mask)
    outputs["layers"] = [zt]
+elif (output == "bottom solder mask"):
+   outputs["function"] = color(White,pcb.mask)
+   outputs["layers"] = [zb]
 else:
    print("oops -- don't recognize output")