Read –only, Property of the ScriptLine : BookFormat.
Displays the number of pages defined in the Signatures property.
•The difference in the value between these 2 properties indicates how many pages are still undefined in your diary.
If the value of this property is equal to that of the # Defined Pages property, then that number is displayed alone (as shown above on the left). If the two values differ, then both are displayed with the number of signature pages appearing second (as shown above right).
By the time you are ready for the final run of your script, the value of these 2 properties should be identical.