Casting Light on Reflectives

This is the first of two Vinyl Graphics columns that will address reflective vinyls. Next month, Oracal's Craig Campbell will cover the topic.

Signs capably serve many purposes in our daily lives. We use them to find destinations, attract potential customers for businesses and promote public safety. When considering safety, reflective film should come to mind. Although many of us take them for granted, the reflective graphics applied to moving vehicles and road signs contribute immensely to our overall safety.

Background

In 1935, the Manual on Uniform Traffic Control Devices required all signs and pavement markers to contain illumination or retro-reflectivity. At that time, retro-reflective, glass-bead sheeting hadn't been invented. In order to achieve reflectivity, signmakers would paint a sign and apply loose glass beads to the wet paint.

In the late 1940s, reflective sheeting contained exposed glass beads on its surface. The next development stage took place in the late 1950s, when film engineers introduced reflective products with glass beads embedded in a clear structure. This represented the first generation of material known as engineer-grade, reflective sheeting.

In the early 1970s, high-intensity reflective sheeting that offered greater reflectivity and durability was introduced for road-sign decoration — these provided 10-year durability, whereas prior, engineer-grade materials typically sustained only a seven-year lifespan. In the late 1980s, prismatic sheeting entered the market and promptly gained widespread appeal as an effective substrate for traffic signage and lightboxes that mark airport runways.

Reflective-film grades

Three types of reflective technology are used in the sign industry: enclosed bead, encapsulated bead and prismatic. Enclosed and encapsulated films comprise glass beads in which the incoming light rays strike the bead and are directed inside toward the back of the sphere. The ray then reflects off a mirrored surface, bends toward the sphere's exterior and redirects light towards the source.

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This technology creates varying reflectivity levels — the output often depends upon the glass bead's size and quality. Thermal transfer and screenprinting are common decoration methods, and certain products can be slit with standard, sign-cutting methods.

Contrastingly, prismatic films reflect the light back to the source using prisms that funnel light. This process eventually redirects the light back to the source, which results in a very high level of reflectivity. Prismatic film represents the newest wave of reflective material.

Prismatic reflective sheet offers brighter white by day and greater reflection at night compared to other types of reflective sheeting. Its reflectivity allows visibility up to 1000 ft. away, which provides drivers with early warning and sufficient response time.

Prismatic sheeting has been classified as long-range or short-range — there are many grades. Premium grades are specifically engineered for better conformability and visibility on public-safety vehicles, such as police cars, ambulances and fire trucks. Also, many varieties are manufactured for conspicuity tapes, fluorescent markings and work-zone products.

Reflective-material specs

As technology has improved, the Federal Highway Administration (FHwA) and other safety-minded governing bodies have enacted many reflective specifications and rules. The FHwA, which has recorded nighttime traffic fatalities since 1978, noted a reduction from 50,331 in 1978 to 42,643 in 2003. Strict rules and specifications regard-ing road-marking reflectivity are considered a contributing factor.

Such government entities as the American Society of Testing and Materials (ASTM) and the American Assn. of Highway Safety (AASHTO) have introduced numerous specifications that federal and state requirements generally observe. The ASTM D 4956 type III/IV specification, an important stipulation, requires high-intensity, retroreflective films with spherical or prismatic lenses adhered to a synthetic, smooth, plastic-encapsulated resin.

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The National Highway Traffic Safety Administration introduced the (49CR571) DOT-2 Specification, which requires affixing red and white reflective material to large, commercial vehicles. The specification directly resulted from a Pennsylvania test that determined conspicuity tape on the sides and back of tractor-trailers reduced crashes by 44%.

Broader potential uses

Although safety primarily triggered reflective-film technology's creation, it's become popular for many other applications. A great alternative to standard, opaque, vinyl films, reflective material makes roadway signs and emergency vehicles more noticeable, and they can boost advertising opportunities.

In daylight, your customer has a bright, colorful, graphic advertisement, and, in darkness, that same advertisement reflects the headlights of passing cars. This reflectivity improves a company's advertising effectiveness day or night. Also, reflective film enlivens a racecar's flames and logos — the retroreflectivity makes night racing a fun and entertaining event.

Installation, storage and removal

Store reflective sheeting in a cool, dry area. The recommendation is 65° to 75° F, with relative humidity between 45 and 55%. Place material rolls horizontally on a vinyl-storage rack, or, in lieu of a storage rack, in the original shipping box. Most vinyl manufacturers ship material in boxes that suspend the product and protect it from damage.

Don't store the material on a hard surface or stack the rolls. This may damage and cause "dead spots" in the film's reflective layer.

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Use reflective sheeting within one year of purchase. And, allow 24 hours for the film to acclimate to the application temperature, prior to installing graphics, if it differs from the storage temperature.

As the material adapts, begin preparing the surface for installation. Assume all surfaces are contaminated. Therefore, clean all surfaces with a solvent if there's a heavy coating of grease or dirt, or isopropyl alcohol for lighter cleaning requirements, and allow the surface to dry completely.

Before installing the reflective film, read the product-data bulletin carefully. Some installation methods and requirements may differ between films. For our products, follow these steps:

• Apply premask to the sign's cut and weeded graphics.

• Squeegee on the liner side to apply even pressure to the film.

• Turn the piece over to place the premask face-up.

• Line up the sheeting on the vehicle or surface; grasp the release liner's edge, and hold the premask down with one hand.

• Begin removing one corner of the release liner from the reflective material.

• Once the corner is in place, continue removing the liner slowly, while using a squeegee to adhere the graphic to the vehicle surface from behind.

• Completely squeegee the entire graphic.

• Remove the premask.

If repositioning becomes necessary, carefully pull the graphics up. Snapping the material may cause "dead spots" in the film. And, don't use application fluid, which may cause an adverse reaction with the film's reflective layer.

To remove the graphics, I recommend working from a corner at one edge of the sheeting — initially applying light heat may make the process easier. Once you've started, work downward until the entire, initial edge is released. Continue removal by gently and slowly pulling the sheeting away from the substrate at a 90° angle. If breakage occurs, begin again until it's completely removed. For best results, pull within 6 in. of the substrate to avoid unnecessary breakage.

Whether your shop services government projects or walk-in customers, an abundance of reflective products allow multiple applications. In addition to the multiple product lines and film constructions available, a rainbow of colors exists. Your opportunities are endless.