Have you ever had a large number of a stamp that looks the same but are different. Post offices around the world use the same image on different types of stamps. Meaning the stamp with the same picture could be printed in a Souvenir Sheet, pane, booklet or coil. They could also be reprints with some small changes. The type of gum could be self adhesive. Or the stamp could be perforated, Serpentine Die Cut, or Roulette. With all these different variation, one kind of stamp could be printed in many different variation. How can we identify these types of stamps? By using different measurement techniques and paying attention to small details. In this article we will use a stamp printed by the United States Postal Service. It is Scott number 2897, 2913, 2914, 2915, 2915A, 2915B, 2915C, 2915D, 2916, 2920, 2920D, 2921, and 3133. WoW! that's 13 different types of stamps with the same picture. But that's only the beginning, because each of these Scott numbers also has different types listed. Let's get started by first identifying each different Scott number. Shown below is a list describing each different Scott number. If you do not have a Scott catalog, look through the stamps you have and write down the differences of each. The list will look something like this:
| Scott Number | Perforated | Serpentine Die Cut | Coil | Booklet Stamps | Date Stamp | Date Stamp Color | Stamp Color Differences | Plate Number |
|---|---|---|---|---|---|---|---|---|
| 2897 | 10.4 | No | No | No | 1995 | Blue | Not listed | No |
| 2913 | 9.8 | No | Vert | No | 1995 | Red | light Blue Shading in Flag | No |
| 2914 | 9.8 | No | Vert | No | 1995 | Blue | Play Gray Shading in Flag | No |
| 2915 | No | 8.7 | Vert | No | 1995 | Red | No | No |
| 2915A | No | 9.8 | Vert | No | 1996 | Red | No | No |
| 2915B | No | 11.5 | Vert | No | 1996 | Blue | No | S11111 |
| 2915C | No | 10.9 | Vert | No | 1996 | Red | No | No |
| 2915D | No | 9.8 | Vert | No | 1997 | Red | No | No |
| 2916 | 10.8 x 9.8 | No | No | Booklet | 1995 | Red | No | No |
| 2920 | No | 8.7 | No | Booklet | 1995 | Blue | No | No |
| 2920D | No | 11.3 | No | Booklet | 1996 | Blue | No | No |
| 2921 | No | 9.8 | No | Booklet | 1996 | Red | No | No |
| 3133 | No | 9.9 | Vert | No | 1996 | Blue | Shy shows color gradation at lower right | No |
Now that our list is completed we can start to separate the pile of stamps. The first step is to select a stamp specification and then create paper labels for each group with that specification. For example, in the above list there are a number of different colored years printed on the bottom of the stamps. Make the number of tags needed to separate all the different colored years. After you have finished separating the years. Some of the colored year stamp groups will require more separating. For example, Scott Number 2913 and 2915 in the list above both have Red 1995 years printed on the bottom. To separate these two Red 1995 stamp groups, find a different specification that each group has. In this case one group is perforated and the other group is Serpentine Die Cut. Separate these two groups and you will be finished. The finished groups will be Scott number 2913 and 2915. Now select the next separated group and check for different types in that group. Repeat this process until all the stamps are identified and separated. When finished, put each group in a glassine bag and tag it using Scott numbers or your own system. Some of the different types of stamps listed above are shown below. Notice the different color date stamps printed on the bottom left of each stamp. Scott Number 2915B has a date stamp in the bottom left and also has a plate number printed on the bottom right.