Wide Format Imaging

People will lather gallons of sunscreen on themselves during summer to protect themselves from ultraviolet rays. The cause of that redness that can make people miserable—ultraviolet radiation—is one reason overlaminates are such a useful part of the wide-format printers' tools.

An overlaminate, in its simplest term, is a transparent film used for graphic protection over other graphics such as floor, fleet, or outdoor graphics. Overlaminates can not only lengthen print life in the sun by acting as a "print sunscreen," but also have the capability to protect prints from humidity and the weather by sealing the print more securely. In floor graphic applications, overlaminates protect from scuffing and slip resistance. Specialty or performance overlaminates can also provide graffiti protection and easier cleaning, according to Jared Johnson, marketing manager, 3M Graphics Market Center.

"Overlaminates are generally required for digitally printed graphics for exterior applications," said Johnson. "Most overlaminates have UV inhibitors in them to help extend the life of the graphic, and reduce fading of the inks. However, an overlaminate can only extend the life of the inks, so the ink formation is very important to the overall life of the graphic."

Remember the old peeling graphics on billboards alongside roadways? In almost any metropolitan area subject to dust, smog, and weather, you will see examples of vivid graphics kept that way for years because of overlaminates.

"Overlaminates really give you a chance to extend the life of your graphics," said Curt Hess, associate digital product manager of the Avery Dennison Graphics & Reflective Products Division. "That's the key to them right now. Most of the inks that are unprotected [will last] about two years or three years, depending on the OEM. By putting an overlaminate on it, you can take it out to five years now."

In today's workflow, sometimes overlaminates and overmasks are combined for processing in one step, according to Hess. If 10 images are the same, the printer will load the printed roll onto a large sealing laminator for roll-to-roll lamination, "and they'll just go from printed roll to overlaminate roll and do the whole thing in one shot."

Ink Check Important

Ink selection is important for the warranty to be extended by overlaminate manufacturers. For example, Karen Buckleman, product specialist, laminates and adhesives, Neschen Americas, stated the guarantee for SEAL overlaminate products at Neschen Americas requires pigmented ink, allowance of adequate drying time before laminating (24 hours or more) and proper preparation of the graphic prior to mounting.