"Transit Marking and Other Messy Issues"
[Column #43, 7/98]
Now that we are in the heart of summer, a look at a problem called transit marking seems appropriate. We are often asked, “How is it that some of the perfect-bound books we’ve done for our customers have passed in-depth abrasion and marking resistance tests and wind up at the customer’s door with severe marking on the covers where the ink has actually rubbed off leaving white spots in those areas?” When we explain that it did not occur during binding or trimming, the usual response is, “Yeah, right. Tell me another one.”
The truth is (contrary to popular belief) it really isn’t caused at the bindery. This mysterious phenomenon is called transit marking...and the problem has become so common, much of the following information was documented in a recent technical bulletin published by a large ink manufacturer.
Transit marking happens as a result of vibrations that occur during the shipping process after all the printing and binding has been completed. It usually shows up as streaks or small patches on the cover (often appearing as white circles) when perfect-bound books rub against each other in their cartons during transit and the ink is abraded away.
To compound this dilemma, transit marking gets worse as the temperature climbs. Incidences occur more frequently in hotter climates and in the summer. The higher temperatures cause the book covers to soften increasing the potential for abrasion. Tis the season...so be wary!
There is also some evidence that microscopic materials, such as dust and spray powders, that inevitably end up between the books, cause transit marking by acting as an abrasive when the books move.
Once we were called to examine some books we had bound because the customer complained there were mysterious white spots on the covers. We arrived to find classic transit marking and a skeptical customer. To overcome his doubts, we first explained that if it was transit marking, the books at the bottom of the skid would display less of a problem because the weight of the cartons at the top would inhibit their movement. When that proved true and he still wasn’t convinced, we decided to place a carton of the books that had not been affected in the trunk of his car for a week to see what would happen. After a week, we pulled them out and found transit marks all over them!
Transit marking is frustrating because printers often hold their breath as the job goes out the door and hope all goes well during shipping. We have used a company based out of Burlington, Massachusetts, called Nancy Plowman Associates (phone number is 781-272-7410) to examine jobs where transit marking occurred. Among other types of consulting, they are an independent testing company in the printing industry and can analyze things such as coatings, glues, inks, and paper. According to them, 90% of the time transit marking is caused by ink problems. After that, only 5% are paper problems and 5% are binding problems. For printers who experience excessive transit marking, a closer look at the inks they are using may be appropriate.
To minimize transit marking, we recommend using 175 PSI cartons (as opposed to the GPO specs of 275 PSI). These lighter weight boxes allow the product in the carton to support the carton rather than the other way around thus reducing vibration. When stacked on a skid and strapped under lots of pressure, these light-duty cartons “give” putting pressure on all the books and preventing movement. Where product will be shipped longer distances, we also recommend using a minimum of four steel-straps on all skids containing perfect-bound material.
Other ways to reduce transit marking include proper cover coating (such as UV, film, and dry varnish) or convenient shrinkwrapping (in singles or multiples) to reduce movement.
Generally, using all these precautions will minimize transit marking...but, be careful! More than one well-meaning salesperson has placed a carton or two of samples in the trunk of his or her car only to show up at the customer’s doorstep with transit marks all over the books. It can happen in less than an hour of driving. The distance a shipment must travel is also directly related to the incidence of transit marking. Be sure to let your binder know if the job will be shipped outside the local area. The longer the books must endure the high-intensity vibrations within the truck, the worse the transit marking problem becomes.
With all this talk about ink dilemmas, I want to mention another issue (likely to make most of us shudder)¾Reflex Blue. It’s no secret that excessive marking, low scuff resistance, and poor drying qualities are common with inks containing 50% or more of Reflex Blue. To better understand why these problems occur, take a closer look at ink fundamentals and the complexity of Reflex Blue ink.
Ink is a blend of clear resins and varnish that control the tack and gloss while giving the substance body. Solvents control press stability and fluidity and drying oils control surface strength, drying time, and “set.” The pigment, which is the coloring agent, is derived from petroleum products and is added to the ink mix in powder form. Although each ink pigment is unique, most have small molecules with a uniform shape and surface area. Reflex Blue pigment molecules are huge in comparison and have jagged, irregular surfaces and shapes. To blend Reflex Blue ink, ink manufacturers must add surface active agents to the mix that allow proper “wetting” of the pigment. As a result, the ink retains a higher level of moisture and takes longer to dry.
Standard “off-the-shelf” offset ink is designed to dry by two methods: absorption into the sheet and evaporation from the surface. When things go as planned (if you can imagine that), most inks will have lost their solvents and have surface set in a few hours. As the ink dries, the smaller, more uniform color pigments settle close together and leave a flatter ink film surface. Reflex Blue pigments, on the other hand, set leaving a jagged ink film surface. Although it may feel dry to the touch, even the slightest pressure will break the molecule’s jagged edges exposing wet pigment. This results in unsightly marks and color transfer to undesired places. Coatings have to be applied after ink has dried. As a result, Reflex Blue jobs often have problems because they require excessive drying time (a luxury in our industry!). UV coating, in particular, does not coat well over Reflex Blue and will sometimes fade or change the ink color.
Paper choice is also a critical factor with Reflex Blue because of scuffing. Minimal marking problems occur with uncoated offset paper, followed by gloss coated. The most marking potential happens with matte finished paper (which should always be varnished).
Issues surrounding Reflex Blue are so common that ink manufacturers have published disclaimers for printers listing precautions without guarantees regarding the outcome of the printed product. They offer these possible solutions to avoid potential disaster:
Use spot or flood varnishing to seal the ink and eliminate scuffing, unsightly fingerprinting, and bronzing of larger ink areas.
Use “Imitation Reflex Blue” ink. Most ink manufacturers have a close match of Reflex Blue containing a completely different pigment blend and without the unpleasant side effects.
Allow considerable drying time on all Reflex Blue projects. Reflex Blue has been known to continue to smear for months after delivery.
Remember...think downline finishing operations when advising your customers about Reflex Blue applications. Press sheets will still have to be cut, folded, and bound all increasing the potential for marking, offsetting, or, worst of all, ruining the publication.