Book Printing: “Wavy” Pages, or Fluting, Can Ruin a Book

An attache at the Embassy of Chile, who had just taken delivery of several thousand perfect-bound books for the ambassador, called me and said that the entire book printing run had “wavy” text. The covers were flat, but the text blocks were consistently rippled. I hopped in a cab and went right over.

The attache and I opened a number of boxes and checked random book printing samples for occurrences of the wavy text paper, and, in fact, he had been right. The problem was pervasive.

Why does fluting occur in book printing?

The technical name of this printing flaw is “fluting.” Fluting occurs in web offset presswork because the paper absorbs moisture during the inking process, and then the drying units of the web press “flash” away the moisture with brief, intense heat. As the paper comes to equilibrium in the web press chill rollers and later on the pressroom floor, the paper again absorbs moisture. All of this happens unevenly. Fluting usually doesn’t occur in the covers of these perfect-bound books because even web printing companies usually produce the covers on sheetfed presses.

The paper weight, paper type, and design (i.e., ink coverage and placement) significantly influence the presence or absence of fluting. Printing companies cannot do anything to eliminate this problem, although over time the waviness relaxes somewhat and the paper lies flatter. In addition, printing companies cannot do anything once fluting occurs, and, until the job is on press, there is no way to know whether fluting will occur.

How can you minimize fluting in book printing?

Fortunately, there are ways to minimize fluting, so keep the following in mind as you design your web offset custom printing job:

1. Lighter-weight paper shows fluting more dramatically than does heavier-weight paper.
2. Heavy ink coverage on the front and back of a press sheet shows the most fluting. If you print heavy coverage four-color process work on one side of the sheet, consider limiting the other side to one color.
3. Uncoated stock shows fluting more than coated stock.
4. Create your publication design, and work closely with your printing companies, to position heavy coverage pages in line with one another to minimize fluting. That is, when looking at an unfolded press sheet (for instance, a sixteen-page signature with eight pages on one side of the sheet and eight pages on the other, with four pages on top and four pages below), the pages with heavy ink coverage should be above or below each other, not side by side.

Good fortune and drier weather saved the book printing run.

Sometimes you get lucky. After it was clear what had happened, I got on the phone with the custom printing vendor. Since fluting is outside the control of printing companies, the printer wouldn’t budge. He was sorry it had happened, but he could do nothing to remedy the situation. Sitting across from me in his office, the Chilean attache was unhappy. He understood what had happened, but he was not pleased that the book printing run appeared to be flawed. And he knew the ambassador would be unhappy.

There was one last resort. When the custom printing vendor had delivered the books to the Chilean embassy, it had been raining. The air had been damp for a number of days. As an experiment, the attache and I put some books under a heavy weight. I called him a few days later, and learned that the fluting had subsided markedly as the weather had improved and the air had turned drier. That gave the Chilean attache a measure of hope. We touched base a few times over the next several weeks, and thankfully the combination of time, dry air, and weights on the books had completely solved the problem.