diff --git a/src/color.cpp b/src/color.cpp
index bcab2257e..7bd4a2db5 100644
--- a/src/color.cpp
+++ b/src/color.cpp
@@ -50,7 +50,7 @@ namespace mapnik {
            << red()   << ","
            << green() << ","
            << blue()  << ","
-           << alpha()/255.0 << ")";
+           << alpha() << ")";
        }
        return ss.str();
    }