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Sellise lainetamise nimi on fluting.

Ameerika rullitrüki ühingu U.S. Web Offset Association seisukoht on:

A magazine publisher recently lost a long-term advertising client because the paper on which the ad was printed looked wavy and therefore cheap. It looked as though evenly spaced parallel ripples ran vertically along the magazine cover. What happened, and what can the publisher do about it?

The technical term for this flaw in printing is "fluting." After a lengthy study of this phenomenon, the Web Offset Association has confirmed the following:

1. Fluting occurs in web offset printing because the moisture absorbed by the paper during the inking process is evaporated unevenly by the driers as it passes through the press ovens. The paper weight, paper type, and design (i.e., ink coverage and placement) significantly influence the presence or absence of fluting.
2. Nothing can be done to eliminate this problem, although over time the waviness relaxes somewhat and the paper lies flatter. Nothing can be done once fluting occurs; and, until the job is on press, there is no way to know whether fluting will occur.

These are rather forbidding findings. Fortunately, there are ways to minimize fluting, so keep the following in mind as you design your web offset publication:

1. Lighter-weight paper shows fluting more dramatically than does heavier-weight paper (although the magazine noted above had more fluting on the heavier cover signature, but for other reasons).
2. Heavy ink coverage on the front and back of a press sheet shows the most fluting (the ad in question was a full-page bleed with heavy coverage on the inside front cover of the magazine; the front cover was also a full bleed with heavy coverage). 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. Position heavy coverage pages in line with one another. Areas of heavy ink coverage above or below blank pages of a publication (as viewed when looking at an unfolded, cut press sheet--one side of a signature) will increase fluting..

Originaal: www.printindustry.com / newsletter_38 . htm

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