The temperature and humidity of a paper storage area and press room can have a big impact on one of the most important components of a printing project — the paper. Paper is very sensitive to changing climates, and printing facilities in colder locales have low relative humidity (RH) can result in tight edges, dimensional changes, wrinkling, and cracking during folding and converting.
Here are some tips for avoiding problems with production during winter months:
1. Place your order far enough in advance to allow for 48-72 hours of acclimation to pressroom temperature.
2. Store paper at pressroom temperature, but not near a heater or cold wall.
3. Do not unwrap paper until it is ready to be printed.
4. If skids or rolls are unwrapped for sampling or testing purposes, they should be re-wrapped immediately.
5. All paper should be properly covered or wrapped with plastic between each pass through a press and after printing is complete.
6. Always score and fold with the grain direction.
7. Scoring is most successful when done wire-side out. All Finch Paper sheet stock, including cartons and skids, are packed felt-side-up. Our Double Thick Cover (DTC) is pasted with the wire-side-out on each side.
8. Always channel score heavier weight papers (100 lb. Text and above) instead of press scoring. We suggest three to five times the thickness of the paper, especially on DTC. Off-line letterpress scores with a rounded rule (bull nose) and channel matrix are also recommended.
9. For heavily inked surfaces, use wider male and female channels to help ease the stress by bending and folding fibers, versus breaking them.
10. Minimum score width formula for each basis weight: 2.5 x the caliper + .008 inches.
(Note: These are guidelines. Each pressroom is different and procedures for maintaining optimal paper conditions may vary.)
SOURCE: Printing Industries of America, www.printing.org