You will need to check for the secret mark, the number and strength of the vertical lines of shading at left and the paper type. If the stamp has only four srong vertical lines of shading between the frame and the portrait oval, the stamp is automatically Scott 209, the most common ten cent Bank Note.

If it has five weaker vertical lines of shading between the frame and the portrait oval, check the paper type. If it was printed on the "hard white" paper, it is either the National or Continental Bank Note printing. If it was printed on the "soft porous" paper, it is one of the American Bank Note printings.

If it was printed on the soft paper and has five weak lines you must check for the secret mark. If the stamp has the secret mark it is Scott 188. If it does not have the secret mark it is Scott 187.

it was printed on the "hard white" paper, you must check for the secret mark. If the stamp has the secret mark it is the Continental printing Scott 161. If it does not have the secret mark and was pinted on the hard white paper, it is the National printing and you must check for grill. If the stamp has a genuine grill, it is Scott 139. If it does not have a grill it is Scott 150.

There are some varieties of these stamps. The re-engraved stamp has a blackish brown shade and is listed as Scott 209b. This is a very distinct shade, almost black, not the dark brown which is often confused with the black brown stamp. The National printings are known from a pale to a dark shade of brown or yellowish brown. The grill is sometimes found split, doubled and as an end-roller grill. A double transfer is known on the stamp without grill.

The Continental stamp is known on ribbed and silk papers, as well as on double paper. It is known with double transfer and with grill. There is also an imperforate between variety with vertical perforations missing. This variety must be collected as at least a side-by-side pair and there can be no blind perfs between the stamps.

The original design 10¢ American Bank Note stamps are known setenant, that is one stamp without a secret mark next to one with a secret mark. The American stamp with secret mark is known in the black brown shade. Cracked plate and double transfer varieties are known as well. The American stamp without secret mark is known on double paper and there is a double transfer variety as well.

The re-engraved stamp is known in a variety of shades, from pale to dark brown, including yellow, orange, purple and olive browns. The black brown as mentioned is a very distinct shade and has its own Scott listing.

The National and re-engraved American stamps are known with the "SPECIMEN" overprint. The re-engraved American stamp is known with the "SAMPLE." overprint.