Follow these steps in the identification of your twelve cent Bank Note:

There is no need to check paper type on this stamp, all 12¢ Bank Notes were printed on the "hard white" paper, but you must still check for the "secret" mark. If it does not have the "secret" mark it is a National Bank Note printing, otherwise it is the Continental Bank Note printing, Scott 162. 

If the stamp was printed by the National Bank Note Company, check for grill to determine the Scott number. If the stamp has a grill, it may be the rare Scott 140. If it does not have a grill it is Scott 151. Care must be taken when authenticating the grill. Many fake grills have been added over the years in an attempt to increase the value of the stamp, although this stamp is so rare that purchasing this stamp without certification is sheer folly.

Watch for re-perforation (to fake a more well-centered stamp), for re-gumming (a major problem with the Bank Notes), and even for bleaching of the cancellation (to remove the cancel). Unused copies carry a substantial premium over the used stamp.

We include the "Special" printings in this identification guide merely for completeness. Only 282 copies total of Scott 173 and 198 were sold, and they were never issued for postal use. We occasionally see uncertified copies of these stamps offered for sale at ridiculously low prices. You can rest assured that the stamp being offered is not genuine. These stamps are so rare, only 135 are known, they rarely come up for sale, except in the sale of a major U.S. Collection.