Coatings and Crackings
Ever received a brochure, booklet or other piece of mail that appears to be cracked along the folded edge? This sometimes occurs with full coverage ink or digital toner when the document is folded unless precautions are taken in advance.
There are three items to consider: Coated papers, toner vs ink and paper fiber orientation.
The Paper Factor
Ink soaks into uncoated paper and digital toner adheres to its rougher surface. Adhesion ability is reduced with a coated paper for both ink and toner. You may get the glossy or satiny finish you like, but you may also experience cracking through both layers – coating and ink or toner.
Specially coated papers will work with non-water-based inks and there are specific papers used with toner based printing.
Should I Choose Toner or Ink?
Most digital toners are made of plastic or wax powders that are fused to the paper using heat. Water or alcohol based inks are commonly used on home inkjet printers; these inks soak into uncoated paper before drying. Glossy printing on a home inkjet printer can only be done using specially coated photo papers.
Commercial printing presses use oily inks that adhere to the paper much like paint.
The Big One: Grain Orientation
To determine the orientation of your paper do a tear test. Tearing with the grain produces neat, parallel strips, against the grain ends with ragged and unpredictably shaped pieces. Take a piece of paper and tear it both on the short end and the long end of the paper to test.
How to Reduce Cracking
For short print runs you will most likely want to choose digital printing. The first line of defense to prevent cracking of toner based pieces is to design without full toner coverage where the fold is to occur. Heavier stock such as card or cover, should be scored whether or not there is toner at the fold line.
Ask your printer if they have a stock that can be run with the grain oriented to fit your fold configuration. Often times a larger sheet paper can be used although the price may be a bit higher.
You could also employ the use of special coatings such as UV, varnish or aqueous. UV coating requires the use of a special ultraviolet light. All three options are available as either “spot” or “flood” coating.
Make sure to use your vendor’s expertise during design and paper selection. They will be able to steer you to the best possible outcome!