This time of year, wherever you look, you’ll see newspaper inserts promoting everything from sporting equipment to jewelry in a frenzy to sell, sell, sell before the holidays. I’ve always enjoyed paging through these circulars, whether or not I end up buying anything.
As I received a new stack of inserts in my mailbox recently, I thought about how these newspaper products are produced. I wasn’t absolutely sure, so I did a little research. Here are my findings.
Printing Inserts on Thin Paper
First of all, you’ll probably notice that the inserts are printed on incredibly thin paper. In addition, they are usually printed in full color.
If you look at the online advertiser rate card for USA Today, for instance, you’ll note that their minimum acceptable paper thickness for advertising inserts is 30# newsprint within a minimum 8-page signature. This sets the lower page-weight limit, and I have seen 35# and 45# as well for thicker inserts.
Paper of this basis weight is much too thin to travel through a sheetfed offset press without being creased, mashed up or folded. Therefore, an advertising circular of this kind must be printed on a web-fed offset press.
That is, the tension of the roll of printing paper traveling through either a dedicated newspaper press or a commercial web press allows much thinner printing paper to keep its dimensional stability throughout the press run.
Heatset vs Coldset Web Offset Printing
If you look closely at a newspaper advertising circular, you’ll see that it is usually either full-color printed on newsprint or full-color printed on a gloss stock.
In the former case, the insert printer can produce the job on a cold-set (or non-heatset) press. Ink printed on such a press dries through the evaporation of its solvent and through the absorption of the ink into the paper fibers. This takes time.
In the case of full-color (4-color process) on a coated sheet, the only option is a heatset press. Such equipment includes an oven following the inking units. The heat of the oven instantly flashes off the solvent in the ink, leaving the ink pigment sitting up on top of the paper. After exposure to the high heat of the oven, the paper passes through chill rollers, which bring the paper temperature down again. By this time, the ink is completely dry.
How About Sheetfed Offset Printing?
I once worked with a commercial printing supplier that did not have a dedicated newspaper press. Instead, this vendor had a Didde cold-set web press that could run 50# uncoated Hi-Brite. The resulting offset cold-web product looked superior to newsprint, was thicker than other newspaper stocks, and had a brightness of about 80 (out of 100). Essentially, its brightness came close to that of an offset press sheet. But again, the Hi-Brite stock was too thin to print on anything but a web press.
Newsprint, Groundwood, and Supercalendered Stock
Many advertising circulars are produced on newsprint. Newsprint is a thin press sheet made by mechanically grinding wood into pulp. It has a lot of impurities, so the paper does not last long. It yellows and becomes brittle. It is, however, a good, cheap paper stock for an advertising insert that will be viewed once or twice and then discarded.
Groundwood is a larger category of paper that includes newsprint. Its name implies that the wood is mechanically ground into the pulp from which the paper is made. If you’re not using groundwood stock for an advertising insert, your alternative is a “freesheet.” A freesheet is free of the impurities of groundwood because it has been chemically pulped rather than mechanically pulped. Chief among the impurities removed in this process is lignin. Such paper is more durable (it has longer paper fibers), brighter, and longer lasting than groundwood.
Your other option is what appears to be a coated sheet, but which in reality has just been passed through sets of metal rollers to achieve a hard paper surface. This is called supercalendered paper. You can buy SCA or SCB paper (the “A” or “B” refer to levels of brightness).
Both of these papers would be good choices for an advertising insert with a more glossy look than newsprint. Of course you would still need to run the paper through a heatset web press to ensure that the web offset inks dried on the surface of the paper rather than seeping into the paper fibers, but a lot less ink would be absorbed into the paper fibers than if you had chosen a newsprint stock.
Because of this superior ink holdout (the ink’s sittting on top of a much harder surface press sheet), the colors would be crisper (and less muddy), and the shadow and highlight detail would be much better than if you had chosen newsprint.
Thickness of Supercalendered Custom Printing Paper
Supercalendered paper sold by one company I found online comes in paper weights from 28# to 45# with a brightness of 65 to 76. Again, this is not very bright (i.e., dingy compared to a white sheet in a print book), but the effect you’re trying to achieve in an advertising circular is totally different.
Why so thin? For one thing, weight makes a big difference when you’re mailing or delivering newspapers with advertising circulars. (Picture a newspaper that’s half again as thick as the one you receive.) For a printed product with such a short shelf life, thin paper works just fine.
Gloss Coated Options for Newspaper Inserts
Your advertising insert doesn’t have to be this thin. It just is a good way to save money. You always have the option of specifying a 50# or 60# gloss coated sheet for even better image reproduction. However, if the paper is too thin for sheetfed work, you will still need a heatset web offset press for your printed product.
This entry was posted
on Sunday, February 8th, 2015 at 5:00 pm and is filed under Newspaper Printing.
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