diff --git a/README.md b/README.md
index ff14f54..59996a9 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,8 @@ This Alpine-based Docker image runs a CUPS instance that is meant as an AirPrint
 * `CUPSADMIN`: the CUPS admin user you want created - default is CUPSADMIN if unspecified
 * `CUPSPASSWORD`: the password for the CUPS admin user - defualt is admin user if unspecified
 
+If CUPSADMIN is not set, the default "cupsadmin" will be used. If CUPSPASSWORD is no set, the name of the admin user will be used.
+
 ### Ports/Network:
 * Must be run on host network. This is required to support multicasting which is needed for Airprint.