A Banner Day for Sewing

According to research by SGIA and others, one of the most common specialty graphics products is banners. They’re in high demand and are relatively easy to produce. But companies that go into banner printing often neglect one of the most important elements of banner production: finishing. Finishing in the context of vinyl banners can involve laminating and other traditional processes that are more familiar to the every day printer. But vinyl and especially fabric banners also require another, unique type of finishing: hemming.

If you have ever hemmed a skirt or a pair of trousers—or have vague recollections of high school Home Ec class—the concept is very much the same: you fold up the edge of the fabric and sew it. In the case of clothing, hemming is done to prevent the fabric from unraveling. In banner production, hemming is done for the same basic reason, but there are other functional reasons to hem banners, be they vinyl, fabric, or some other flexible material. Hemming reinforces the edges, important if you will be adding grommets to the edge (a grommet is a small metal ring affixed in a hole punched in the edge of a banner through which rope, twine, etc., will be threaded to hang the banner) and at the same time gives it a smooth, “finished” look. Hemming is also performed to add pockets for poles, banner stands, or the other hardware that will be used to hang or otherwise display the banner.

There are a number of different techniques for hemming banners. For vinyl banners, it is common to use tape. Very low tech, it is simply a double-sided adhesive tape that is applied to the back of the banner, the edge is folded over, and sticks to the tape. The placement of the tape determines whether it is simply a smooth finished edge, or a pocket for a banner pole or other display hardware.

Tape isn’t suitable for all substrates and it may lack the strength some applications require (about which more in a bit), so a common alternative is sewing. Sewing or hemming a banner (vinyl or fabric) is not appreciably different from hemming clothing or other textiles: you fold down the edges and run the printed material through a sewing machine which stitches the hem.

There is a third alternative technology for doing banner hemming, and that is welding. That’s another story for another time, and while some banner producers find it to be a better alternative than traditional sewing, it may not be for everyone.

“We stayed with sewing for the vast majority of banners because we have the system set up and we have the people and they’re really good at it,” said Tom Trutna, President of Big Ink, an Eagan, MN-based producer of banners, trade show and event graphics, floor graphics, signage, and more. “If I was starting from scratch today, welding would probably be a bigger part of it. If you didn’t have the skill set, it’s probably easier to learn how to weld than learn how to sew.”

If you have ever tried to mend—or indeed hem—your own clothing, you know very well that sewing requires a certain degree of skill. Even as more and more sewing machinery adds levels of automation and, like an increasing amount of finishing equipment these days, requires fewer and fewer skill sets to operate, it still requires some skill to operate it, and operate it correctly.

High-quality sewing and hemming is important not just for aesthetics, but for basic functionality. A poorly stitched hem may not adequately support the display hardware. This becomes especially acute when creating banners for outdoor display, where they can be subject to all weather extremes. In a storm or in high winds, the stitching may be all that keeps a sign or banner from pulling free and sailing away.

“Outdoor conditions are huge,” said Trutna. “If [a banner] is going outside even for a short period of time, you have to take wind load and how it’s being hung into consideration. The biggest issue we have with our finishing tends to be weather. You have to build these things for worst-case scenarios.”

The winter of 2015, for example, frayed a lot more than just people’s nerves. Last winter, Big Ink did construction site wraps for a client on the East Coast,. “We did hundreds and hundreds of feet of construction fence mesh, and we finished it the same way we’ve finished things for years and years,” said Trutna. “Then they had the ‘storm of the century’ on the East Coast and some of the hems ripped out. We had never seen that before.” As a result, Big Ink has started routinely adding reinforcements to the hems and the corners of their outdoor banners and signage. “It ends up being the manufacturer’s fault, so we have to prepare for that now.”

Hemming is not just a finishing concern, but a prepress one, as well. Taking into account where the hem will be (the hem margin) and where the stitching will appear is vital to account for before printing, and it is not uncommon for banner printing newbies (or even pros) to discover that the hem or stitching falls right where the client’s logo or other essential content appears. (This is also an important consideration when adding grommets to banners and signage. You don’t want to poke a hole through an important image area or text.)

Trial and error led Big Ink to devise a color-coding system for identifying hems and sewing marks. “There’s one color that’s the cutline, one color that’s the sewing line and we put them right on our proofs so the client can see exactly where the stitch line is going to be, so it’s not going through some key logo or text,” said Trutna.

RIP modules designed specifically for textile and banner printing—like Onyx Software’s Textile Edition, Caldera’s RIP software to name but two—can also let you set and preview hem margins and sewing marks. EFI’s Fiery proServer and Fiery XF software have settings for adding grommets and pole pockets. Companies doing banner production quickly set up a process for proofing and previewing where these things will go.

So, when adding new kinds of specialty products and services like banners, the ink-on-substrate part of the process is the easiest, but it is the less obvious post-press steps that can take shops by surprise, and the need to acquire sewing machinery and skilled operators to run it, can take many by surprise.

It kind of makes you wish you paid more attention in Home Ec classes.