Q&A: Preventing Transit Marking

by Kevin Rickard, Rickard Bindery
The Kraft surface of a corrugated carton is a very abrasive paper product. Separating unprotected finished product from Kraft surfaces is important whenever movement is possible.

The most discouraging thing about transit marking is it happens after jobs have been beautifully produced. Transit marking is just as its name implies – unwanted marking that occurs during shipping. Unless preventative measures are undertaken, abrasive paper surfaces can rub against each other and cause markings as products are jostled around in trucks. The presence of microscopic grit, such as press powder or carton debris, can cause unattractive scratching in a paper’s surface.

Product movement within a box during shipping is the major cause of transit marking and happens on many types of printed products, including brochures, saddlestitched projects and books. Although there is no way to predict with certainty which jobs will experience transit marking, preventative steps can and should be implemented to minimize the likelihood of problems.

Question: How do you determine if a job is at risk for transit marking?
Answer: If the outside sheets have moderate or heavy ink coverage and lack any paper coating (i.e., UV coating, varnish, aqueous or film lamination), extra care should be taken in packing the product. Before your bindery begins working on a job that may transit mark, check for wet ink by running your hand across sheets, searching for tackiness. Unfortunately, even if your ink is dry and the job has been flood varnished, there is still no guarantee that transit marking won’t happen – especially if dull varnish was used. Generally speaking, you’re less likely to have marking problems if gloss varnish is applied “dry trap” (a separate press run) instead of “wet trap” (the same press run as the ink).

For saddlestitched books, consider the physical characteristics of the book itself. High gloss enamel stock reduces ink penetration and causes ink to rest high on the paper’s surface and can be easily scratched or chipped off. Heavy books with unvarnished enamel covers are highly susceptible to transit marking. If products have diecut areas, pockets, half-size sheets or any other uneven surface levels, marking may occur along raised edges after pressure is applied – much like a brass rubbing.

Be careful of printed products with heavy dark ink coverage on one side and light coverage on the other. Any time heavy ink rests against light ink after packing, the chances of markings increase. If reflex blue ink is present, then the problem becomes worse because it dries so slowly. Other inks to be careful of include red, purple and metallics.

General weather conditions also are a significant factor. High humidity is problematic because it can hinder the drying process of both ink and varnish. Also, high heat may moisten ink, increasing its tendency to scratch. Even if weather conditions are good in your area at the time of shipment, consider where the job is to be shipped. In the Midwest, the weather can change within hours. In general, as the distance of the final destination increases, so does the likelihood of transit marking.

Question: Is there a means of testing printed materials to see if transit marking will be a problem?
Answer: Unfortunately, there is no foolproof way to guarantee the prevention of transit marking. A simple test is to rub sheets together with moderate pressure by hand and look for ink either flaking off or transferring to the opposing sheet. If this happens, the odds are that there will be shipping problems, unless counteracted. For a better test, bind and pack enough books to completely fill a box and place it in a jogger for a while. Afterwards, if there isn’t any sign of transit marking, the job probably will be OK.

Question: How can transit marking be prevented?
Answer: Tightly packed, properly coated finished products that don’t slip when jostled should successfully ship without transit marking. The first step in avoiding unwanted marks is to choose the proper carton size and have product within the carton tightly bundled, whether it is via paper bands, shrink wrapping, poly-tying or rubber banding. Printed products should fit snugly without corners being damaged and filled to the top of the box. Loosely packed products will slide around in cartons and mark easily. If gaps within boxes are unavoidable, your bindery should add substantial packing or filler materials to remove the voids. Wadded paper at the top of an under-packed carton is next to useless. Fortunately, there are a lot of options to fight the war against transit marking including the following:

  • Shrinkwrapping. Shrinkwrapping is the best way to prevent marking, as well as dust, dirt and foreign contamination, but it’s expensive. It offers excellent protection because shrinkwrapped contents don’t shift. In addition, it allows removal of a portion of the contents.
  • Paper banding and poly-tying. Paper banding and poly-tying are among the best forms of bundle containment. Like shrinkwrapping, properly banded and poly-tied products don’t move during shipping. These are good, low cost methods that prevent many marking problems.
  • Rubber banding. Rubber banding is very useful for miniature products. However, this method has the tendency to cut at the point where it holds the sheet.
  • UV coating and film lamination. Both UV coating and film lamination seal ink behind a durable, scuff resistant coating.
  • Aqueous coating and dry trap varnish. Press-applied aqueous coating offers more protection than varnish, but less than UV coating and lamination. If you use varnish, apply it “dry trap” (separate pass) for better protection against scuffing.
  • Slip-sheeting books. Slip-sheets absorb excess friction and significantly help prevent marking. Unfortunately, slip-sheeting is expensive because additional packers are needed at the end of production lines. If slip-sheets are used, make sure that they are exactly the same size as the finished product.
  • Separate products and cartons. The Kraft surface of a corrugated carton is a very abrasive paper product. Separating unprotected finished product from Kraft surfaces is important whenever movement is possible. Laying a smooth sheet of paper on the bottom of a carton before inserting product will help prevent scratching. Laying another smooth sheet on top of product before sealing the carton is even more important because items at the top of cartons are more subject to slippage.
  • Skid wrapping. It’s important to keep cartons secure on skids during shipment. Transit marking shouldn’t occur if boxes are well packed and skids are stable as trucks start, stop and make sharp turns.

The best way to prevent transit marking is to take the time to predict which jobs are the most likely to mark and then develop a plan to combat the problem once identified. Choose a binding partner knowledgeable about transit marking and work together to adopt preventative measures on a job-to-job basis. With a good game plan, your customers won’t be rubbed the wrong way.

Rickard Bindery specializes in discovering solutions to challenging folding, saddlestitching, gluing and other bindery jobs. For more information, call 800.747.1389 or visit www.rickardbindery.com.