For Printers
Welcome to Inking the Deal from International Paper, a series of e-mails containing news and practical advice for those involved in the business of printing. Every six weeks, starting with this issue, you’ll receive another e-mail full of information we’ve gathered through in-depth interviews with printers, print buyers and other industry experts.
In this issue:
- How changes in technology are changing the processes (and speed) of printing.
- How the paper industry is responding to new printing technologies.
- How and why commercial printing papers are better than 10 years ago.
- Technical factors that affect how paper is manufactured today.
Printing and paper. What a difference 10 years can make!
Although this article is intended to give you an inside look at what’s happening to today’s commercial printing papers, we need to begin by exploring printing technology precipitating the need for changes in paper.
Printing technology has changed more in the last 10 years than it did in the previous 500. Digital presses, stochastic screening, waterless inks and hi-fi color are just a few of the dramatic innovations affecting your business.
Today, the versatility and capabilities of computer and image processing software are shaping the future of printing. Electronic imaging, which dominates prepress, is extending to platemaking and printing itself. Offset presses are coming close to automatic control of inking, dampening and color speeds in excess of 2,500 feet per minute. Binding and finishing continue to be automated.
What’s the future of printing?
Industry experts believe that lithography will continue as the dominant printing process of the 21st century, but flexography with water-based and ultraviolet (UV)
inks and gravure with electromechanical and direct digital engraving will grow in use at the expense of letterpress. By 2025, it’s predicted that the breakdown of printing products will look like this:
Lithography 35 %
Flexography and gravure-like processes 37 %
Letterpress, screen printing and other plate processes 7 %
Electronic digital printing 21 %
Electronic presses are changing how printing is done. While the average turnaround time for an offset lithography job today is one to two weeks, it’s predicted by some that by 2005, that time will be reduced to an average of one day.
How the paper industry is responding.
Paper companies are working feverishly to develop and improve papers that can take full advantage of the enormously improved capabilities of new printing technology. New papers have to meet numerous production and conversion requirements demanded by the new technology – and still convey the esthetic elements of a print job. Paper-producing companies also must be environmentally aware and keep a close eye on their production costs.
Much of the new technology involved in papermaking is complicated, but it’s helpful to know about the process to understand the changes being made to produce paper that works better for commercial printers.
The papermaking process.
Anyone who knows paper knows that it’s made primarily of wood pulp. Wood is stripped of bark, chipped and turned into pulp through a process that uses a combination of chemicals, heat and, sometimes, mechanical grinding. After the pulp is in a semi-liquid form, it is bleached to give the finished paper the desired degree of brightness. Then dyes and fillers are added to give the final sheet a specific color and property. This might include rag content from cotton fibers or titanium oxide for opacity and brightness.
When the pulp contains the right components for the paper being produced, it’s fed out to the "wet" end of a machine where it is laid out to form a crude continuous sheet. While on the wet end of the paper machine, a "dandy" roll is used to compress the sheet and distribute the fibers. Next, it’s fed into a press section, where the water is squeezed out between rolls and felts. The final process dries the product to a desired level and results in recognizable paper. The paper is then "calendered" or finished, after which coatings are added to coated sheets and the paper is cut to form smaller rolls or "sheeted."
Better papers to fit better printing equipment.
Three properties of paper have changed dramatically in the last few years:
- Coatings are much smoother, allowing for better printing surface.
- There has been a dramatic increase in whiteness and brightness (although the average human can’t see two or three points difference in brightness for the same shade). Brightness and whiteness don't make paper better, but they add contrast that can make images stand out better. (These attributes are being driven by the market and not papermakers.)
- Opacity is much better because papers now have a higher amount of fillers, but those added fillers reduce the amount of fiber, making the paper "flimsier" with less body and stiffness. The paper’s caliper and thickness is still the same but fillers are added to improve opacity. Despite this, the paper is strong and more stable than old papers (less stretching and distortion). Improved technology also makes coatings more consistent. Calendering is better and overall paper quality is more consistent.
Modern papers allow better use of printing equipment (such as computer-to-plate systems) and, at the same time, produce a better finished product. And production technologies have led to marked improvements in a number of the physical, optical and performance characteristics of papers. Most of today’s printing papers are specifically designed for particular printing systems, such as offset, gravure, flexo or digital.
Every good printer knows the characteristics of paper – finish, coatings, grain, opacity and basis weight. They also know the difference between coated and uncoated papers, bond, book, offset, index and newsprint. Selecting the right paper is something you learn over time as you gain knowledge of the uses for each type. But as technology changes, so do the considerations in paper selection.
Choosing papers for the printing process involved.
In general, most papers can be used for the offset process. The dependant in this equation is the intended use. The end product is a combination of design and paper used. There are many papers designed for the flexo process. Flexo requires a different paper in many cases, to handle the water-based inks. Gravure, because of its cell-based printing, usually requires a smooth sheet that will handle solvent-based inks. Choosing paper is important not only for the printing process, but for the end use (direct mail, brochures, books, etc.).
Digital papers can pose new problems. Being qualified as "digital" does not necessarily mean they can be run on all digital equipment. Some pieces of high-end digital equipment, such as the Indigo®, Xeikon®, etc. will require special or qualified paper. Much of the digital or laser-compatible paper will work in laser
systems (copiers, printers, etc.). Usually if a paper is digital-guaranteed, it will work in laser and inkjet systems.
Papermakers today must make, in many cases, paper that works for offset, lasers, ink- jet, etc. This puts a lot of physical requirements on the sheet. Hold out for oil-based offset, toner and heat from the laser fuser, but still build a different type of holdout for liquid ink-jet. This puts a lot more design and technology into a piece of paper.
Trends in paper production.
Current trends in paper production include efforts to conserve fiber, use lighter basis weight sheets with higher ash content and use more recycled fibers. Introducing new fillers allows the production of paper with high opacity and lower paper weight. In the days of acid papermaking, clay was used which gave papers a beige color. The use of calcium carbonate has allowed papermakers to add a higher amount of filler and still raise the whiteness and brightness levels.
Printers today can expect more uniformity in their papers, too. Every International Paper mill, for instance, is equipped with state-of-the-art process controls that test paper continuously for moisture, smoothness, caliper, color and brightness. Tolerances are also tighter, producing paper that achieves better results because it’s more consistent and easier to run.
The revolution in the printing industry is just beginning, and with it comes tremendous challenges for paper manufacturers and exciting innovations for those involved in commercial printing. International Paper is pleased to report that those challenges are being met through research designed to continue improvements in paper.
Note: The information contained in this module of Inking the Deal from International Paper reflects the opinions and ideas of various persons interviewed on behalf of International Paper. International Paper shall not be responsible for reliance of the information contained in this module.
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