Production: Understanding Why Specific Ink Compositions Work with Certain Printing Processes

By: Jerry Simpkins

Mark Twain has been credited with the quote “Never argue with a man who buys ink by the barrel.” Many other famous wordsmiths have been credited with this saying, including H.L. Mencken and Ben Franklin.

The basic premise of the saying seems to be if a newspaper editor or publisher doesn’t agree with a viewpoint you are advocating, you may have to endure a long series of negative articles in their publication. While we continue to endure challenges with the printed product, this statement, at least to me, continues to express the true power of the printed press.

When I first got into the newspaper business, a stogy old ink salesman threw this quote out in conversation. Being new to the business I just chuckled and went along with him, trying to act like one of the good ‘ol boys who had some kind of idea what he was talking about (I didn’t).

Fast forward to today, and I now truly understand the meaning of the saying. I am immensely proud of what it stands for in my mind, which is freedom of the press.

When I started writing this article, I researched some of the technical aspects of ink, such as composite, viscosity, tack, etc. I also received some very useful information from some of the top ink vendors in the country. After scanning through the facts in preparation for this article, I decided that instead of taking strictly a technical approach, I’d like to tie things back to the effect on our customers and the effect on our industry.

Putting the Customer First

If you’ve been in the publishing industry for awhile, you’ve addressed several complaints about ink on fingers, rub-off and smudging. I once had a customer screaming at me because she read the paper on her lap while wearing a new white dress. That one simply didn’t end well for me and I actually ended up buying the customer a new dress (when it comes to newspapers, you just can’t make this stuff up).

I’ve lost track of how many customers claim they are canceling their subscription due to how “dirty” their newspaper is. Ink rub-off can be a real issue. So what causes it?

Let’s start with “Does ink really dry?”

The short answer to this is for cold set inks, no. News ink absorbs into the substrate. Known as penetration, absorption or saturation into the sheet, many different things can affect the “drying process.”

Black ink, which is the most widely used color in the newspaper, is obviously what readers complain about most often. Rub-off/ink transfer is dramatically impacted by the type of raw materials that are used to produce the ink. The higher the quality of the ink, the less rub-off, but typically, the expense is higher.

If you’ve shopped ink in your career, you no doubt noticed that vendors market “news ink,” “low rub” and “no rub” ink. What controls drying is oil, resin and pigment selection in the ink. Most vegetable or plant based oils are very slow to dry. Soy inks have been popular for many years and are more environmentally friendly than petroleum based products. While petroleum based inks have properties that vary drying time, an ink that is made entirely with soy would not dry at all.

Buying ink is a process similar to buying gasoline. Buy cheap gas and your car can knock and run poorly; upgrade to a mid-grade octane increases and your car runs better. Then, if you want the best performance, you’ll spend the money and upgrade to premium. Depending on what you want to spend, you can certainly minimize your issues with rub-off.

Newsprint, which is the common paper we use in the industry, must have low tack inks due to porosity and surface roughness. As we move to lower gram newsprint and switch between suppliers, drying can be affected. In cold-set printing, most drying occurs by the paper absorbing ink, but will still rub off on fingers even after extended periods of time. This is a direct result of the cold-set printing process.

Just for the record, other processes dry in various ways and actually do come out dry.

  • Sheetfed dries by oxidation; reacting to the oxygen in the atmosphere.
  • Heatset printing dries by evaporation; flashing off the VOC’s as the printed web passed through the oven to flash and “set” the wet ink film.
  • UV inks are converted from a wet ink film to a solid as they pass through the UV light source and are cured.

Another challenge with ink in our industry is set-off, the transfer of ink onto adjacent pages.

There are three primary offenders I see that contribute to set-off (all can be controlled or eliminated to a degree).

The heavy handed press operator. As circulation draws have changed over the years and many of our runs have been reduced in number, the use of densitometers has diminished. On many runs, by the time you’ve set your inks, the run is over and densitometer readings simply aren’t practical. The other issue that can come up here is short staffing. If your press crew is running around adjusting registration and water balance, they tend to take their eye off the ball when it comes to setting ink. The result is over-inking and saturation of the sheet. This contributes to rub-off and set-off and tends to be one of the biggest causes of reader and advertiser complaints.

Every publisher I’ve ever worked for has a different opinion of how much ink is right. Some like a dark/dense application of ink, others like a light/even flow across the page. Beauty is in the eye of the beholder, but don’t forget what it impacts, mainly reader complaints and quality of the final printed product.

To me the solution is simple. Talk with the publisher and the ad director to find out what the general consensus is, then come as close to that as you can on press. Keep on top of the press crew. This is where many of our problems come in—pressmen who like to set the ink heavy.

Besides the problem of set-off and rub-off, there is also expense. A normal density setting for black ink is 95 to 105. For each point you set over 105, your ink usage increases quite dramatically. I’m honestly not sure of the formula (your vendor can help you here), but there is a point not awfully high over the maximum recommended ink density that ink usage doubles, and so does your expense and related printing issues.

Setting your nips too tight. As the web pulls/passes into the folder through the nips and trolleys, your adjustments are critical and can complicate set-off. Over-tightening can in some cases help pulling the sheet, but will also create the “racing strip” effect as it passes through. Take the time to set your press up right and it will minimize ink related problems.

Use good quality ink. Granted most of the time you’ll pay more, but that even remains to be seen. I’ve struck up deals with vendors for special mixes/ improvements on ink for no additional cost. It doesn’t always work, but the old adage of “If you don’t ask, you’ll never know” is true. Speak with your vendor, show them the issues you’re having with their ink and explain your goal. Often they can formulate the ink differently and eliminate the issue without increasing the cost to the customer. Nothing ventured, nothing gained.

No matter how we try we will never have completely dry ink in our newspapers, but we can come close. High speed presses and the general cold-web process can complicate the issue, but so can many of the controls we mismanage in our operations.

Totes of cyan, magenta and yellow ink wait to be connected to the ink lines and be pumped to the press. Ink is typically sold in three primary vessels: kits, totes and bulk, depending on order volume and the needs of the print site. (Photo by Jerry Simpkins)

A Quick Word on Tack

Inks can be formulated with various tack to work with the specific printing processes, such as cold-set, heat-set, UV, etc.

Uni-tack inks can be useful in newspaper printing and have become more common in our industry than step tacks used in the heatset and sheetfed application. Uni-tack inks were developed due to additional four-color process work on lower grades of paper, i.e. newsprint.

Tack can be defined as the amount of force required to separate an ink film. For this reason, a traditional tack rated set of inks is preferred in most types of offset printing. Tack values on cold set ink can run as low as 3.0 on an Inkometer; in comparison, a high-end sheet-fed ink may have a value approaching 20. Newsprint and commercial stock simply cannot handle the pull of a high tack ink.

Trapping and Lay Down Sequence

Lay down sequence and ink trapping are both important parts of the printing process and critical aspects in the outcome of the final printed product. Simply put, trapping is the ability of one ink to overprint another ink. The key control aspect of trapping is delegated by lay down sequence; i.e. which color ink is applied to the press sheet first, second, third and last.

The most common and highly used lay down sequence in cold web offset printing is CMYK (cyan, magenta, yellow, black). If you’ve ever worked in a shop that laid down differently, you will understand the challenges the wrong sequence can create. I’ve worked in shops where pressmen insisted that they had the best sequence for that particular press. More times than not, this resulted in orange colored reds and complaints to advertisers about shifts in their logo colors. Laying down outside of the vendor recommended color sequence will almost always result in extreme color shifts and unsatisfactory color reproduction.

One of the best explanations on trapping and the lay down sequence was provided to me by Dale Morningstar of Central Ink: “The ink sequence decades ago was YMCK. This was changed to CMYK due to issues with color reproduction. The reason it was changed was with this sequence, the reds shifted to orange, blues shifted to green. For example, if you run a green screen and use 100 percent yellow and 50 percent blue screen in YMCK sequence, 100 percent of the yellow will print but not all of the 50 percent blue will ‘stick/overprint’ to yellow. There is a significant detail increase and trap efficiency in midtone through shadow tone and solid areas.”

With all this said, many printers still prefer to lay yellow down first in order to hide any imperfections in registration. I don’t agree with this approach but whatever works best in your shop and produces the result you’re happy with is always the right way to go.

As is the case with many aspects of the newspaper printing process, we, as the printer, can be our own best friend or worst enemy. Meeting with vendors to better understand material issues, following tried and true SOPs and addressing in-house challenges appropriately to ensure we’re following the best procedures can often fix 99 percent of any problem we may have.

 

Lastly, I would like to thank Central Ink, Flint Ink and U.S. Ink for their input for this article. While I’m sure there are other top quality suppliers in the newspaper market, these three suppliers have always stood out when I had a question to ask and have provided tremendous customer service to our industry and myself as a whole.

 

Jerry Simpkins is vice president of the West Texas Printing Center, LLC in Lubbock, Texas. Contact him on LinkedIn.com or at simpkins@tds.net.

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Published: November 19, 2018

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