I managed to track down an affordable source of the elusive "Black Pearl" paint that was used on Vader in the original trilogy. I am not the originator of this information, but with this information I managed to find an online store for it. I hunted high and low for them at Wal-Mart and it's possible not every Wal-Mart has a modelling section. So hopefully this will help. I noticed that WalMart has some very good prices on paints and this online store's prices isn't too bad either.
Valspar is the company that supposedly manufactured the paints used for the Star Wars costumes. I believe the ANH facemask uses "Black Pearl" and "Galaxy Gray". It may still be true with TESB and ROTJ.
Kustom Kolor is by Valspar.
Black Pearl (this is the special gray paint you'll need)
http://www.bigestores.com/siteid11/defa ... lack+pearl
You will also need the "Black" and "Clearcoat".
Now, if for some reason you need this, they offer the Galaxy Gray but it's way brighter. The facemask is supposedly using Black Pearl.
Galaxy Gray (if you need it for some reason)
http://www.bigestores.com/siteid11/defa ... alaxy+gray
I would welcome any verification of this information.