Bulk improvement

1. Change furnish.
— in newsprint, balsam gives a higher bulk than fir.
2. Change beating/refining.
— increase stock freeness to increase bulk.
3. Reducing the filler content within permissible range has a marked effect on bulk, but opacity is also impacted.
— opacity can be independently controlled to some extent, if brightness permits, by using a neutral pigment such as TiO2.
4. Change the line pressure at the presses.
— this can only be done effectively with controlled crown rolls.
5. Change the formation, where formation is not a problem.
6. Ensure correct operation of calender stack.
(a) to increase bulk:
— raise calender rolls (with a fixed crown king roll this will necessitate jacking).
— supply drier paper to the stack, e.g., shut off sweat dryer.
— increase percent crepe.
— shut steam off steam rolls.
(b) to decrease bulk:
— decrease percent crepe.
— use a breaker stack.
— use additional rolls on stack.
— supply more moist paper to stack.
Note: Watch for hard and cracked edges.