Text Pages Expansion – Web VS Sheet Fed Paper
In the web process, often not all of the product is processed by a web press. It is commonplace to have a “plus cover” project where the text is printed by a web press and the covers are printed sheet fed. With plus cover projects, many times the cover is a heavier paper such as 80lb. cover weight and higher. In these situations, once the product is printed and bound, the text pages can experience “growth” (or expansion to be more exact) on the inside pages of a magazine, catalog or brochure.
How Expansion Occurs
Text growth or expansion is not a binding matter. Rather the answer lies within the paper. Sheet fed paper is manufactured at a higher moisture content around 5% compared to web papers. Web paper is manufactured at a lower moisture content of around 3% to 3-1/2%. Once the product is printed via web press, the paper runs through a heat-set dryer which further reduces moisture levels of the paper. By contrast, the sheet fed process does not dry the ink using the high temperature oven process like a web press does, so the paper will not lose moisture during the printing process.
After each component is printed (covers and text pages) and then bound together, the trimming process nets an even cut to the head, foot and face on the project and everything is even at that phase. Once trimmed, and moisture is reintroduced to the paper, the text pages (printed web) will expand as the fiber in the paper now takes on additional moisture. The amount of expansion can vary depending on moisture levels that existed in the the paper (both pre and post press) and the current levels of humidity in the air once the product is trimmed.
Expansion on the web portion of a project is a phenomenon which is common in the industry, and viewed as a product which is accurately produced. The manufacturing reality is the end product can have text pages with growth when using multiple printing processes to produce a plus cover project.
As the publication matures, cost and revenue growth can become a concern. At this point, many magazine and catalog publishers may consider lighter-weight papers that maintain a quality image, yet significantly reduce overall printing costs. The selection of lighter-weight papers includes coated freesheet, lightweight coated groundwood papers that are available in a range of basis weights and finishes. Before making any significant changes, however, publishers and catalogers should determine the effect that a change in paper stock may have on the customer satisfaction, advertising effectiveness and brand identity.
Coated groundwood papers are an excellent option for lightweight, highly portable publications that are text-heavy, and have full ink coverage and minimal white space. Many magazines, particularly those with limited shelf lives, have successfully migrated from coated freesheet paper to coated groundwood papers, including business-to-business, trade, hobby and special-interest magazines. Titles such as Time, Newsweek and Victoria’s Secret are excellent examples of highly successful titles that are published on lightweight coated groundwood stock. Coated groundwood papers offer publishers a high-quality look and feel by providing increased opacity at the selected weight with good gloss coating for vibrant printed images.
To make lightweight papers more attractive to magazine and catalog publishers, some paper manufacturers have increased the brightness of some coated products and have worked to improve paper’s print quality. Unique cost-saving products also have been introduced to the marketplace.