Stained; dark (4)
I believe the answer is:
inky
This clue is a double definition.
'stained' is the first definition.
(thesaurus)
'dark' is the second definition.
(I've seen this before)
(Other definitions for inky that I've seen before include "Like the printing trade" , "Leaked on by pen" , "Jet" , "Black; drunk (Aus. sl.)" , "Like writing fluid" .)