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Offset vs. Digital Printing:
What You Need to Know about the Differences

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Does the full color printing in USA Today seem as good to you as the color printing in GQ Magazine? Many consumers would say yes, and if you’re one of them, you will probably not notice any difference between a book produced in a digital plant and one printed by an offset book manufacturer. But lots of people will. Don’t get me wrong. I’m not saying that digital printing is bad. I’m saying that it is different and that it looks different.

 

Cover Quality

The modern digital color cover presses are very good. Bearing in mind that I threw away my loupe (the magnifying glass used for checking registration and dot structure) years ago and that my eyes aren’t what they were when I got into the business in the 1970s, it’s still noteworthy that I can hardly tell the difference between a process color cover printed on a digital press and one printed on an offset press, as long as there is a film lamination on top of the printing. (Without the lamination, it is pretty easy to tell the difference, but no publisher in their right mind would sell a book without a laminated cover.) Where solids or gradated screens are involved, banding and other inconsistencies can be unpleasantly apparent. But still if I were to give digitally printed covers an overall grade for appearance, it would be a B+ (vs. an A for the offset covers).

 

Troubles with Images Added to Text

Digital text printing has also come a long way. Most often, the equipment used is Docutech, which is made by Xerox®. For straight type, it looks fine. Although it produces a much darker/denser black than offset because it uses toner and not ink, it passes muster with no loupe and no glasses.

The problem arises when you try to insert even the simplest graphics or halftone images. There is no comparison between the appearance of the graphics and halftones done on a digital press and those printed on a traditional offset press.

Our book, Publishing Basics: A Guide for the Small Press and Independent Self-Publisher, reproduces the same images and graphics on five different paper stocks using three different digital presses and two offset presses to let people see the differences for themselves. (Yes, the baby pictures are me and my partner Dana, and the other pictures are my son and Dana’s dogs.)

Besides its Docutech sample, the book shows samples from Océ and Scitex digital presses. The Océ does a better job with halftones than Docutech because it fuses the toner into the paper instead of laying it on top of the sheet, but it is priced considerably higher. The Scitex actually uses ink, which is good, especially for text, but its halftones are the nastiest looking. All in all, the three digital presses get a B+ for text and a C- for graphics, compared to the A quality of offset.

 

When Heat Happens

Up to this point in the process, the difference between offset and digital printing is the difference between an A and a B, neither one a bad grade by most people’s standards. But now we’ll move on to some of the more subtle differences.

Have you ever unpacked a ream of copy paper, loaded it into a copier, and run off 500 copies? Does the pile of copies have the same physical appearance as the pile of paper you loaded in the feeder tray? Ever try to put the copies back into the same package that the blank sheets came from?

Copiers, like most digital processes, utilize extreme temperatures to fuse the toner to the paper. This heat removes moisture, tending to make sheets fresh from the copier brittle. Natural humidity may restore some of the paper’s original moisture eventually, so that if you leave the pile of copies out for a while, it will start to flatten. But it will never get back to looking the way it did in the beginning. By contrast, the offset presses that print single-color books do not use any heat. The sheet that goes into the press is unchanged when it comes out.

 

Binding Takes a Toll

Picture a digital printing line. The “book block” (a pile of sheets) comes out of the copier and goes right into the binder, where the sheets are sealed on the binding edge with adhesive for applying the cover. You now have a book block picking up moisture on three sides and not the fourth, which can produce a curl to the whole book that will never flatten out. This problem by itself gives the overall finished digital book a C-C+ look, bringing the whole product’s grade down to a C+; still “commercially acceptable” but bothersome to many customers.

Another typical problem arises from the strength of the binding. In the perfect binding process used with both offset and digital books, the groups of pages known as signatures are gathered to make a book block. Then the binding edge goes through a grinding unit that “roughs up” the edge so adhesive will adhere better when the cover is applied. After the cover is wrapped around the book, the book block gets trimmed on the outside, top, and bottom.

A typical new perfect-binding machine used by offset book manufacturers can cost more than $2 million. The perfect binders that digital shops use generally cost between $20,000 and $100,000. The difference between the two types is a lot more than markup. Most binders used by digital printers produce little more than a glorified pad. Easily 95% of the complaints that I have run into about digital products involve the binding and 75% involve pages falling out as people flatten the book out so that they can read it.

 

The Price of Going Against the Grain

The main culprit when pages fall out is actually the paper’s grain. Paper is made primarily of pulp and water (as well as chemicals to regulate brightness and opacity). In simplest terms, the papermaking process begins when pulp is added to water to make a sort of pulp soup. As this solution moves through the papermaking machine, the pulp fibers line up next to each other in parallel rows. Moisture is removed until the mixture becomes paper. The direction that these pulp fibers are facing is the “grain” of the paper.

All paper has a grain. If you take a piece of 8_” x 11″ copy paper and fold it the long way, you get a nice smooth fold. Fold the same sheet the short way and the fold will be ragged and irregular. The heavier the paper, the more pronounced this effect. You always want the grain of the paper to run parallel to the binding edge of the book so that the pages will open naturally. If the grain goes against the bind, the book will not lie open. Readers will try to flatten the book to keep it from snapping shut. This will end up breaking the spine, and there go the pages.

Most digital presses run an 8_” x 11″ sheet of paper. Unless specially ordered, the grain of the paper is 11″–a wrong grain for a 5_” X 8_” book. (Similarly, short grain paper will yield a wrong grain 8_” X 11″ book.) Judging from the sample books that I’ve received from various digital printers, most of them don’t worry about using correct grain paper.

 

When You Decide on Digital

Your best bet if you want to buy digital printing to save money, to get the job done faster, to print tiny runs, or for any other reason is to find an old-line book printer who made a move into digital printing instead of using someone who has always been a digital printer. Chances are good that the old-line printer is used to running books with correct grain paper and to binding books that don’t fall apart. Chances are also good that the company runs a real perfect binder, not the bargain basement version run by most digital shops.

Most straight digital book printers lack the experience and the money to do better, which means that as a buyer you need to be clear in your mind about what you’re buying. If a printer is quoting you under about 750 copies, the job is probably going to run on a digital press. Do yourself a favor when dealing with one of these printers and confirm that at least the paper grain is going to be correct. If they don’t know what you are talking about or tell you that it doesn’t matter, hang up the phone and try someone else.

But as you can see, you are not going to achieve A or even A- quality with digital printing, no matter how much you want it to happen. If high quality is what you need, you may have to raise your print order for an offset printing plant or put your money back in your pocket until digital quality improves and try again in a few years.

 

 

Ron Pramschufer, who has been in the printing industry for more than 30 years, co-founded RJ Communications, a print manufacturers’ representative organization, in 1994, and it launched www.BooksJustBooks.com in 2000 as a print buying service for small publishers and self-publishers. You can order a free copy of the book “Publishing Basics” at that site and you can “Ask Ron” any question about the manufacturing process by writing to ron@rjcom.com.

 

 

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