The print finishing process is full of hidden complexities. Even the simplest folding jobs can generate unforeseen problems and questions. Most print finishing difficulties arise from working with paper. Although paper may appear simple on the surface, there’s quite a bit more to it.
It’s All About Paper
The oldest known sheet of paper dates to around 179 BC in China. You’d think that after 2,000 years, we’d have solved all of paper’s mysteries. Most paper is made from the cellulose fibers in wood pulp, though some papers are made from cotton fibers. “Sizing” is added as a filler to paper in order to reduce its ability to absorb water. This is what makes it possible for inks to stay dry on the surface. Clay coatings or calcium carbonate can be added for varying degrees of glossiness. Dyes and pigments can create different colored papers.
The Physics and Chemistry of Paper
Paper folding and finishing performance relies on the size and orientation of the fibers, and that depends largely on the species and origins of the tree. Many complex mechanisms contribute to forming the fiber bonds that create the network we call paper. Then we get to the manufacturing process, and a whole host of factors further affects the performance of paper:
- Treatment process of pulp.
- The bond between coating and paper base.
- Coating thickness. More coating can provide a higher gloss, but may be harder to fold and more susceptible to cracking.
- Fiber content. You can achieve more stability in a single sheet with higher fiber content.
The Press Room
Once paper reaches the press room, that’s when things start to get really sticky. The whole printing process involves making paper less flexible, more brittle, and harder to finish. Paper gets saturated in the press room with inks, coatings, and varnishes–chemicals that are not always fully understood. Each one bonds to paper and to each other in unique, complicated ways. Even the smallest change can completely alter how your printed job runs when it gets to the bindery. The environment and relative humidity (RH) can also play a huge role, a low RH can cause static problems and fiber cracking.
When you add up all the variables that come into play, it’s a wonder how anything ever gets done! However, with the right skills and printing equipment, no job is impossible.
Atlantic Graphic Systems Is Your Premier Printing and Binding Equipment Supplier
Established in 1976, Atlantic Graphic Systems has been a premier equipment sales and service provider for forty years. The technology of printing has been integral to the communication of ideas and information for hundreds of years. We’re proud to work in this historic and dynamic field. If you’d like to order equipment or services, call us at 410-290-8200 or visit our Contact Page. Want to keep up with the latest news and information? Follow us on Facebook, Twitter, Google+, Pinterest, and Linkedin! 1