The invention relates to a recording material for the production of offset printing plates, having a web- or plate-form support, a radiation-sensitive layer on the front of the support and a continuous, pigment particle-free layer on the back of the support. The present invention provides a compound represented by formula I and a compound represented by formula II, and processes for preparing 4-acetyl-2,3,4,5-tetrahydro-benzo1,4diazepine by using the compound represented by formula I, the compound represented by formula II and o-nitrobenzaldehyde. Further, creases L1, L2 for inserting the projection Pa into the slit S while surrounding sheets P2 existing between the front cover P1 and the back cover P2 are formed in the back cover P3 of the sheet bundle PA by a crease forming portion.