The large banknote issues, Scott #134-218, span almost 100 Scott numbers. They were printed by three different companies between 1870 and 1890: the National, Continental, and American Banknote companies.These issues are well documented in the philatelic press and the Scott US Specialized catalog. The 90˘ issue is a special case in this series.
Unlike other Large Banknote issues, there are no secret marks on the 90˘ value. Therefore, identification of this stamp is more challenging than other values from the Large Banknote issues.
Let’s ignore Scott #177 and #202. These are special printings and they are very rare. Most genuine special printings are accompanied with a certificate of authenticity. That leaves five othe Scott numbers possible for this issue. They are as follows:
Scott #144 is grilled, similar to the 1869 Pictorials (Scott #112-122). It is valuable. Used copies catalog at $2500. Because grills are often faked, I recommend a certificate of authenticity on any Scott #144.
Scott #218 is printed in purple ink. Identification is very straightforward.
Scott #191 is printed on soft paper. Here is a trick on how to identify soft versus hard paper. For a hard paper example, use Scott #114 which is only printed on hard paper. For a soft paper issue, use Scott #210 which is only printed on soft paper. Hold the center of the stamp with tongs and gently bend the corner of the stamp with the tip of your thumb. Allow the stamp to slip off your thumb and listen to the sound it makes. Hard paper stamps (like #114) make a sharp, snapping sound. Soft paper stamps (like #210) make a dull, thumping sound. Also, the hard papers feel more rigid compared to the soft papers. It takes a little practice, but you’ll soon be able to hear the difference in the papers. Keep your #114 and #210 close by and refer to them.
The only difference between #155 and #166 is the ink color. Scott #155 is a dark carmine and very sharp appearing. Scott #166 is a pale carmine and, to me, has a slightly brighter appearance than the #155. Scott #155 is darker and similar to Scott #319, but not quite as dark as the lake color of #319. Scott #166 is brighter and more similar to Scott #250.