Meaning of "a" or "b" after Scott # on US plate blocks such as J84a or J84b.
As a buyer of US stamps and plate blocks, I continually see a Scott # with a letter after it such as "a", "b", etc. For example, on Postage Due plate blocks for 1931 on Hip, J84 is listed as J84, J84a, J84b, etc. Are these Scott designations? Should I get a Scott Catalog or other reference? Thank you, Frank
Comments
1. Errors (inverted designs, e.g. C3a Inverted Jenny, missing colors, etc.)
2. Perforation varieties.
3. Stamps that are issued as se-tenant pairs, blocks, or panes with many designs, such as the DC Superheroes and many others. The major number will be assigned to a fully intact pair/block/pane, while each separate stamp design will get a letter suffix.
4. Souvenir sheets sometimes get a major number and sometimes a letter designation (minor number), getting the basic number of the highest value stamp of the set it was issued with.
5. Booklets. The individual stamps in a booklet will get the major number, while a complete booklet pane will get the suffix.
There are other examples, also. As they say at the ballgame, you can't tell the players without a scorcard, and the Scott Catalog is the scorecard you need to tell the stamp players apart.