Depends on xcolor package

README.md

@@ -5,6 +5,7 @@ Refresh your `texhash` or similar, and then you should be able to load the follo
 \usepackage{uuprintcolorscmyk}
 \usepackage{uuprintcolorsrgb}
 ```
+(note that these sty files depend on `xcolor`, so make sure to add `\usepackage{xcolor}` too)
 
 and the following classes:
 ```