diff --git a/lib/galaxy/tools/parameters/basic.py b/lib/galaxy/tools/parameters/basic.py
index be1ed9002c0d..eda07c0503fd 100644
--- a/lib/galaxy/tools/parameters/basic.py
+++ b/lib/galaxy/tools/parameters/basic.py
@@ -833,7 +833,7 @@ def __init__(self, tool, input_source):
         input_source = ensure_input_source(input_source)
         super().__init__(tool, input_source)
         self.value = input_source.get("value", "#000000")
-        self.rgb = input_source.get("rgb", False)
+        self.rgb = input_source.get_bool("rgb", False)
 
     def get_initial_value(self, trans, other_values):
         if self.value is not None: