What Sets Prismatic Reflective Tape Apart from Glass Bead Tapes?
Glass bead tapes and prismatic tapes are the 2 types of reflective tape available on the market today. The first reflective tapes used glass bead technology and were invented by 3m in the 30’s. Then Reflexite invented micro prismatic tape in the 1960s. It is interesting that even though prismatic tapes have been around for over 50 years, they have not replaced glass bead tapes entirely. This is due to the fact that both have characteristics that, in certain circumstances, make them desirable.
Glass Bead Reflective Tapes
To bend and reflect light back to the light source, glass bead retro reflective films use small glass spheres. Glass spheres reflect light less efficiently than prisms because of the imperfections and curved surfaces in the beads. Because of this, glass bead tapes are about 30% efficient. This inefficiency can problematic for certain long sight distance applications. But even though glass bead retro reflective tapes are less bright, they have at least four distinct advantages over prismatic tapes.
First off, reflective tapes using glass beads are substantially more affordable due to manufacturing being less complicated. Second, the majority of glass bead tapes can be easily cut using CAD software and a plotter, allowing you to make reflective signs and graphics by cutting out letters, numbers, and designs from the film. Third, glass bead engineer grade type 1 tape is available in the largest color palette, giving users more choices that any other reflective film. Fourth, glass bead tapes return light at broader angles. In contrast to prismatic tapes, which are more like light spot lights, glass bead tapes are similar to flood lamps. This is depicted in the diagram below.
The diagram above shows you that glass bead tape scatters light more than prismatic tape. This explains why it loses brightness as you move farther away. The greater angle of dispersion may, however, be advantageous at close ranges. Let’s take the case of a firefighter who is equipped with high-intensity glass bead tape. When someone shines a light in his direction, the tape will light up for both the person shining the light and, if you are somewhat close, for you as well. The fireman’s tape also rapidly illuminates as the beam draws closer to him. Again, this is a result of light dispersion. For close-up situations, a lot of people prefer high intensity glass bead tape. Prismatic is always preferable for long distance applications. This is due to the fact that a prismatic tape can be seen for over a thousand feet or more, while a glass bead tape is visible at a distance of only a hundred or so yards.
Glass bead reflective tapes can be divided into two categories. A typical engineer grade or type 1 tape is the first, reflecting at around 75 candelas for white. It can be found on automobile tags, stop signs, speed limit signs, emergency vehicle striping and graphics, among other things. This tape is the most widely used. High intensity, often known as type 3 tape, is the second kind. In a honeycomb pattern, this tape encloses beads with a higher index. White high intensity tape reflects at a light level of about 250 candlepower. Both road barrels and traffic cones often use this type of tape.
Prismatic Reflective Tapes
As much as 80% of the light that is directed at prismatic film is returned. Because of this efficiency, it is more visible than glass bead tapes from farther away. Prisms are more efficient since the mirrors are flat rather than curved. Due to the tape’s increased focus, the light it emits can travel further, thus increasing visibility. Prismatic tapes are required for long distance applications like DOT-regulated trucks or coast guard search and rescue retro reflective films. Prismatic tape comes in a variety of grades, ranging from type 4 to type 11. Close in, the many varieties don’t necessarily differ greatly from one another to the human eye, because they are all so bright. The difference becomes apparent as you move farther away from the tape. Oralite SOLAS coast guard authorized tape from Orafol is the brightest reflective tape. In search and rescue operations where the lost individual may be a thousand or so yards away, a micro prismatic tape like SOLAS is vital.
The majority of prismatic tapes are thick, and have a hard acrylic surface. This makes CAD cutting difficult. Oralite metallized prismatic tapes are an exception. Metallized Prismatic films, invented by Reflexite (now Oralite), have just one thin layer. Two benefits result from this. First off, unlike tapes that are thicker and made in multiple layers, these tapes won’t delaminate. Second, a vinyl cutter/plotter can be used to cut these films using CAD software just like glass bead tapes can be cut. The benefit of this is substantial. Compared to normal glass bead graphics, prismatic graphics can be seen much further away, giving this film a clear advantage in certain situations. Color choices are more limited though.
The following is a short list of the different types of prismatic tapes: DOT C2 Tape, FRA Railcar Tape, SOLAS Coast Guard Tape, School Bus Tape, Chevron Reflective Striping, and Sign Sheeting.
In conclusion, both glass bead and prismatic tapes have their applications and will remain relevant and useful for many years to come.
Steven Cole (Economics, MBA – University of West Florida , Business & Innovation – Stanford University) 25 years of experience in the reflective safety business. Specializing in vehicle accident and rear end collision reduction through increased visibility.