IMPERFORATE BOOKLETS

 We’ve recently learned stamp booklets sold in full uncut sheets have some stamps that are partially imperforate.  Press sheets of sheet stamps don’t have these imperforate varieties – only booklet press sheets do.  When these sheets are finished into booklets, the booklets are cut apart.  But on unfinished press sheets the booklets remain attached.  This makes some stamp blocks and pairs horizontally or vertically imperforate between – where the cut would have been made between two different booklets.