Retro reflective tape is defined as a film that through the use of glass spheres or man made prisms, reflects light or radiation back to its source. Glass bead tapes reflect using microscopic glass beads that act as parabolas and direct light back to where it came from. Prismatic tapes use man made prisms or mirrors to collect light and send it back to its source. When a transparent color is applied to the surface of either tape the light that is reflected is colored.
Reflective and Retro-Reflective surfaces are often confused with each other. A surface that is Retro-reflective is always reflective but a surface that is reflective is not always retro-reflective. For example, a mirror is reflective but not retro-reflective.
(Note – retro-reflective tape is normally shortened to simply “reflective tape”.)
One of the most important features of retro reflective tape is its ability to collect light, change the color of that light and send it back to its source. That is why stops signs are visible at night in a red color. Yield signs are visible at night in a yellow color. And so on. Without this feature, night time driving would be different than it is now.
The types and colors of reflective tapes are mind boggling. The huge variety of applications are what create the need for all the different intensities, types and colors. For example, trucks need a bright red and white alternating dot tape that can be seen from thousands of feet away. Life vests need a super bright white tape that can be seen from even farther away. The life vest needs a sewable reflective tape whereas the truck does not. Stop signs in neighborhoods can basic affordable reflective tape that uses glass beads for reflectivity. However, street signs on interstates need a more expensive prismatic film. Distance is what dictates this necessity.
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By definition, retro reflective tape is a film that either through the use of glass spheres or man made prisms, reflects light or radiation back to its source. (Source – Cambridge English Dictionary)
This seems like a simple task but in fact it is quite complicated. Just like a portrait that stares at you no matter where you are in the room, reflective tape reflects light back to the source and the source only no matter where that source is positioned. Think of it this way. If you were in the correct position in front of a parabolic shape like a satellite dish and threw a ball into the dish it would always bounce back and hit you. If you throw a ball into the corner of a racquetball court it will hit one wall, then the other, and then come back to you. (In both examples you need to be in the right spot.) Glass bead retro reflective tape (original technology) would be like the satellite dish and prismatic retro reflective tape (newest technology) would be like the racquetball court.
The picture below shows 4 types of tape side by side photographed at different distances with a flash camera. The two tapes on the left are glass bead tapes (engineer and high intensity). The two tapes on the right are prismatic (V92 and SOLAS) As you can see the prismatic tapes are visible from much farther away.
Oftentimes, reflective and retro-reflective are confused with each other. All retro-reflective surfaces are reflective but not all reflective surfaces are retro-reflective. Consider a mirror. It is reflective. However, if you shine a light on it at an angle the light will bounce and hit somewhere else. That is because it is reflective but not retro-reflective. If the mirror was retro-reflective the light would always come back to you.
Here is a diagram that will visually show you how these films work. The first diagram is of a glass bead type reflective film. This is the original technology. The tapes are about 30% efficient and tend to disperse light back in a wider spread. For close up applications this is actually a good thing but for distance applications it is not. The pattern is similar to a flood light. Bright up close but not as bright at a distance.
The diagram below shows how prismatic tape works. Prismatic tape is much more efficient (80%) and reflects light back in a tighter pattern. The reflecting beam would be much like a spot light. The beam stays tight and together out over a longer distance. (example – lighthouse beam which is concentrated via the use of a lens into a tight beam that reaches out to ships.)
Lastly, it is important to remember that the tighter the beam, the more your eyes need to be in line with the source of the light for you to see it when it is reflected back. Car headlights and the drivers eyes are in this basic configuration which is why the driver and passenger see the street signs light up and a by-stander off to one side will see no reflection at all.
History of Reflective Tape – Who Invented it? – Online Store
(Summary – 3m invented glass bead reflective tape in the 1930’s and Reflexite invented micro-prismatic reflective in the 1960’s.)
Lets start with the basics. Reflectivity was not invented. It has always been present in nature. Light bouncing off of objects is why we are able to see those objects. Retro-Reflectivity has also always been present in nature. A cats eye is an example of this phenomenon. (parabolic lens creates a retro reflective surface) So retro reflectivity was discovered, not invented. What was invented was an artificial way to reproduce these characteristics in a usable form.
There have been two breakthroughs in the technology of retro-reflectivity. The first is the perfectly spherical glass bead and the second is the man made prism. Both of these discoveries play a big part in the history of reflective surfaces and tape. Lets start with the glass bead.
Potters, an American company, began producing tiny glass beads or spheres in the early 1930’s. The beads that Potters created were very round or spherical which was important. Only a perfectly round and clear bead would send light back to where it came from. These very small and very round glass beads were used on cinema screens to make them brighter and also on road stripes to make them more reflective. To this day glass beads made by Potters are still used on road stripes. The paint is applied and while still wet the beads are sprinkled on top. That is why at night the painted lines show up so well. This is all because the round beads sit up from the paint surface just a little, take in light from your headlight, and bounce it right back to you. Sort of like a parabolic mirror.
At first, glass beads were applied to the surface of signs and left exposed. The reflectivity achieved was low and in rain it was even lower. Also, over time, dirt would build up between the beads and further limit visibility. This experimentation was a start, but further improvements were needed. In 1937, 3m began developing a film that utilized glass beads bonded to a flexible surface. Their intention was to use this tape on road surfaces but after some durability issues they switched their focus to road signs.
To create a brighter tape, 3m created a base layer or film that was a silver color like what is on the back of a mirror. They then applied glass beads to this surface so that about half the bead was embedded in the silver and half was exposed. The silver backing turned the back of the bead into a mirror and the shape of the bead provided for the return of light back to the source. To protect the reflecting beads, a clear layer was applied. This resulted in a much brighter product. The clear layer kept the beads protected and made the tape visible even when it rained. (Note – by tinting the top coat, different colors were created) In 1939, 3m introduced what was known then and today as “engineer grade” reflective sheeting. It was first used in trials in Minneapolis and then in the UK. Later, improvements in engineer grade tape would be made by using advanced mirroring techniques and higher index beads. Also, variations in the top layer allowed some versions to stretch and conform and others to be stiffer. The type that conforms is used for vehicle applications, traffic cones, and road barrels, while the type that is more rigid is used for signs. Engineer grade is also known as an enclosed bead sheeting. This simply means that the beads are immersed in the top coat so that each bead is sealed and protected. There are pros and cons to this type of construction. On the plus side, you can cut the tape and make letters or shapes and the integrity of the glass beads are unharmed. It is for this reason that engineer grade tape is so popular in the graphics industry for letters, shapes and designs cut in the material. On the negative side, this type of construction reduces the overall reflectivity of the beads. Engineer grade or type 1 film reflects at a rate of about 75 candelas for white and less for the colored films. The same as your car tag. For applications within 100-150 feet, this is more than sufficient.
High Intensity Grade Glass Bead Reflective Tape – ASTM D4956 Type 3
In 1971, 3m introduced their “high intensity” reflective sheeting. This tape or sheeting is different from engineer grade in that the beads are enclosed in cells but not completely encapsulated. They sit in a honeycomb type hexagon cell and are sealed in by a clear or colored top coat. Also, instead of sitting in a metalized layer, the actual beads themselves are metalized. Being metalized themselves and not being encapsulated makes the beads much more reflective. In fact, high intensity sheeting is about three times more reflective than engineer grade sheeting. High intensity sheeting is very popular for sign backgrounds. Since cutting the tape opens up the cells and allows water to intrude it is not often used for letters or shapes. (NOTE- only the cells that are cut are affected. All other cells remain sealed. Plus the cells are very small) High intensity or type 3 sheeting represents the brightest tape that can be created using glass bead technology. Roughly 250 candelas for white. High intensity sheeting was and is used extensively in sign making. Since signs are static the material performs well. And the extra reflectivity allows vehicles to see it much farther away.
Competition Enters the Glass Bead Reflective Tape Market
In the 1970’s several companies also entered the glass bead reflective tape market. Avery Products launched a line of engineer grade reflective tape in the United States. Avery merged with Dennison and became Avery-Dennison in 1990. Seibu International, a Japanese company, launched a similar line overseas. Their sheeting was known as Seibulite. In 1991 Seibu was purchased by Nippon Carbide (also a Japanese company) and the product was renamed Nikkalite.
Prismatic Reflective Tape – ASTM D4956 Type 4 and above
In 1963 the American Rowland brothers, of Rowland Products Inc, began developing micro-prismatic retro-reflective sheeting. This was done in cooperation with Luce Reflexite and later with Fresnel Optics. These companies were later merged together. This product was patented in 1970 and a company called Reflexite was created to produce and market the new product. Reflexite began selling micro-prismatic sheeting in 1973. Just as 3m is credited with the invention of reflective glass bead tape, Reflexite is credited with the invention of prismatic reflective tape. (Reflexite has since been purchased by Orafol)
Prismatic sheeting reflects light back to the source just like glass bead tape does. The only difference is that prismatic retro reflective sheeting does this much more efficiently. Instead of light entering a glass sphere it enters a triangular prism. Micro prisms have straight sides that allow more light to enter and exit the prism. Prismatic tapes are about 80% efficient while glass bead tapes are about 30% efficient. Also, prisms are man made and are placed side by side in a tight array while glass beads will have some dead space between the beads. Just like glass bead tape the microprisms are also mirrored on the back. The front of the prism allows light in and the back reflects it and sends it back out. Like glass bead tapes, micro-prismatic or cubed cornered tape comes in two types, metalized micro-prismatic and encapsulated lens.
Metalized film is popular in the graphics industry because it is made in one thin layer and will not delaminate. It has the same positive features that engineer grade has but is 10 times brighter.
Encapsulated or non metalized prismatics are thicker and are more prone to delamination. However, the colors are a little more vivid due to the absense of the silver mirror coating. Because of this, for sign sheeting, non metalized films are preferred.
In the 1980’s Stimsonite, a major manufacturer of road reflectors launched their own prismatic sheeting. They were subsequently purchased in 1999 by Avery-Dennison who was then able to add Stimsonite micro-prismatic sheeting to their glass bead line.
Nippon Carbide, the company that acquired Seibu, developed their own line of micro-prismatic films and were then able to offer a full line of reflective products from engineer grade glass bead tape to prismatic sheeting.
In 1989 3m launched a prismatic product known as diamond grade sheeting thus completing their line of reflective sheeting products.
In 2012, Reflexite Americas merged with Orafol. Orafol is a German company and has an impressive global presence. Before the merger, Orafol had a large line of reflective films. (mostly glass bead technology) This line more than doubled with the addition of the Reflexite prismatic reflective products.
At the present time, there are four major competitors in the reflective tape business. These are 3m, Orafol/Reflexite, Avery Dennison and Nikkalite. All four companies have a glass bead and prismatic line. 3m is actually the least competitive in the glass bead market now. Their strategy has been to focus on prismatic tapes and slowly discontinue the glass bead line. Whether this is a good move on their part is yet to be seen.
You see reflective tape every day and every night. But have you ever stopped to think how it works?
Reflective tape (also known as retro-reflective tape) works by reflecting light back to the light source only. In other words, the tape only lights up for the person with the light source or in line with it.
For example, lets say two people were walking down a street with one person on each side of the street. If person “A” has a flashlight and shines it down the street at some reflective tape on a trailer the tape will light up for them. However, the person on the other side of the street will probably not see the tape light up. If both shined a light down the street they would both see the tape. This happens because the tape contains either glass beads or prisms that collect light, focus it and bounce it back to the source.
How does it do this? Imagine that you are in a round room and you are in the center of the room. If you throw a ball towards the wall it is always going to come back to you. Reflective tape works in a similar manner. The diagram below shows how the glass beads or prisms do this.
As you can see from the diagrams above, the tapes refract or bend light in such a way that it always goes out the way it came in. That brings up another amazing capability of the reflective tape. In the first diagram one person had a light an the other did not. If both had lights, both would see the tape light up. What is amazing about this is that the tape does not have to be horizontal to the viewer for it to reflect light back. It can also shine multiple beams back in multiple directions. Flat against the light is best but even at sharp angles you will get a good return of light.
Another thing to remember about reflectivity is that your eyes have to be in line with the light for you to see the tape reflect. Next time you are out driving at night and are behind a tractor trailer truck notice how you can see the reflective tape light up when you are far back. As you get close at a stop light you will notice that the tape no longer lights up. This is because the angle from the light to the tape and then to your eyes has become too great. In other words, it makes a big difference where the light is in relation to your eyes. If you were holding the light close to your head then the reflectivity would not change as you moved closer. In our article on the difference between glass bead tape and prismatic tape we will cover the geometry of reflective tape in more detail. We have a complete line of products at our main store website www.tapedealer.com .
How Glass Bead and Micro-Prismatic Reflective Tape Are Made – Online Store – www.tapedealer.com
Reflective tape is made using machines that bond together multiple layers of material into one film. There are two main types of reflective tape, glass bead and micro-prismatic. They reflect in two different ways but are made in similar fashion with glass bead tape being the less complicated of the two to product.
Engineer Grade Glass Bead Reflective Tape
Engineer grade reflective starts with a carrier film that is metalized on the top. Glass beads are applied to this layer so that about 50 percent of the bead is embedded in the metalized layer. This gives the beads their reflective properties. Then a layer of either acrylic or polyester is applied over the top. This layer can be clear to made white reflective tape or it can be colored to create the different color reflective tapes. A layer of adhesive is then applied to the bottom of the tape and a release liner is applied to that layer. It is rolled up, slit to width and then sold. Note – an acrylic layered film will not stretch and a polyester layered film will. Because of the heat used in the manufacturing process engineer grade films end up being a single layer so they will not delaminate.
High Intensity Glass Bead Reflective Tape
High intensity type 3 reflective tape is made in layers also. The first layer if one that has a grid built into it. Normally a honeycomb type pattern. This pattern is what will hold the glass beads so that they are in separate cells. The glass beads are bonded to the bottom of this cell then a layer of acrylic or polyester is applied over the top of the cell so that there is a small air space above the beads. (high index beads) This layer can be clear or a color. Then a layer of adhesive and a release liner are applied to the bottom of the tape. Note – an acrylic layered film will not stretch and a polyester layered film will. Although the layers in high intensity are bonded together, they can delaminate.
Metalized Micro-Prismatic Reflective Tape
Metalized micro-prismatic reflective tape is made by first creating a prism array out of clear or colored acrylic or polyester (vinyl). This is the top layer. This layer provides reflectivity and returns light back to the source. A colored layer would return light back to the source but in a different color. This layer is metalized to enhance its reflectivity. Then a layer of adhesive is applied to the back and a release liner is applied. Because of the heat used in this process the layers of metalized prismatic will not delaminate. This is especially beneficial in applications such as vehicle graphics or any other application where the tape may be treated harshly. Reflexite invented prismatic reflective tape and their tapes do not delaminate.
Non Metalized Micro-Prismatic Reflective Tape
Much like metalized films, the first step in creating non metalized reflective films is to create the prism array out of acrylic or another clear resin. This will be the top layer of the film. It can be clear or colored. In order to create a whiter or a more vivid colored film, the prism layer is adhered to a grid that forms a sort of honeycomb pattern. This creates an air layer below the prisms. The surface below the air layer is white. The prism layer and the grid layer are bonded together but can come apart meaning that non metalized films can delaminate. By eliminating the metalizing of the prisms the tapes are more vivid since the color does not have to compete with the silver metalizing layer. Non metalized films are more vivid but not necessarily more reflective.
The image below shows the 4 types of reflective films. All are made in a similar way. The glass bead engineer grade film is the easiest to make and thus the least expensive. The high intensity is the next easiest and next in price. The metalized micro-prismatic films are the most expensive to make but are the brightest and toughest of all the reflective tapes. They are perfect for dynamic or harsh environments. The non metalized films are less expensive to make than metalized films. Non metalized films have the advantage of being more vivid in the daytime and are popular for sign sheeting and other static applications.
The word “retro” is the key to understanding the difference between a reflective surface like a mirror, and a retro reflective surface like a bike or automobile reflector. Retro means to go back or backward. In the reflective tape industry it means to return light back where it came from and no where else.
A mirror is reflective but not retro reflective because it sends light in different directions depending on the entrance angle. If light was a tennis ball it would be like throwing the ball at a wall at an angle. The ball would hit the wall and ricochet at an angle very similar to the one that it arrived on only the other direction. Now imagine a wall that curved around you so that when you threw a tennis ball at it the ball would always return to you. That would be called retro reflective. The diagram below illustrates this.
How a retro reflective surface works is a matter of geometry. Glass bead retro reflective surfaces use glass spheres to collect light and bounce it back to the source. The rounded shape of the beads is what creates the retro reflectivity. Prismatic surfaces do the same thing but with sharp angles like prisms. They work like the glass beads but are more efficient thus creating a brighter return of light.
I have people contact me all the time asking the question “Which reflective tape is the brightest?”. The quick and easy answer to this question would be a white or silver colored micro prismatic retro reflective tape. Reflexite SOLAS would be an example of this grade and color of tape. It is used for marine applications to help rescuers find people or lifeboats.
The better question would be “Which reflective tape is best suited for my application?”. In other words brightness is only one factor to consider when choosing a reflective tape. There are other very important factors to consider as well. These are color, flexibility, price, longevity, adhesion, contrast, competitive lighting and light dispersion. It is because of these other factors that so many different types and colors of reflective tape are manufactured. In this article I want to go through the different types of reflective tapes and list their basic characteristics. The main focus will be on brightness but I want to summarize the other factors at the same time.
In each section below you will see that the brightness or reflectivity of a tape is affected by type (construction of the tape) and color. The brightest tape in each class is always white (silver). I also want to mention that all tapes are bright close up. It is as you get farther away that you begin to notice a difference.
Note – The picture below shows our white/silver reflective tapes in order of brightness. The least bright on the left and the most bright on the right. Keep in mind that brightness is not always the only consideration. For example, if you wanted to wrap a bike frame in reflective material you would use the tape on the left. (engineer grade) That is because it has other properties that outweigh brightness. In this case, conformability. The good news is that the price also goes up from left to right. Engineer grade is very affordable and SOLAS is very expensive.
Flexible Engineer Grade Type 1
Engineer grade retro reflective tape is a type 1 material with glass beads providing the retro-reflectivity. It is a thin, flexible material and is molded in a single layer which prevents delamination. It comes in the widest variety of colors and is also the least expensive and most popular of all the tapes. It is used in a variety of applications where viewers will be fairly close to the tape itself. Engineer grade comes in a standard and flexible grade. The flexible grade will stretch and is used in applications where conform-ability is important. If you have a rough uneven surface to mark then this is the tape you need. (example – bicycle wrap) This material can be computer cut into letters, shapes and numbers and is widely used on emergency vehicles and signs for this reason. It is often combined with a brighter background so that both colors are reflective but a contrast is still achieved. Because it is a glass bead tape it disperses light in a wide angle. Recommended for applications where the viewer is within 50 yards of the tape.
The estimated brightness of this grade in the different colors measured in candelas is as follows:
White – 108 candelas
Yellow – 88 candelas
Gold – 78 candelas
Orange – 54 candelas
Green – 28 candelas
Red – 21 candelas
Blue – 12 candelas
Black – 10 candelas
Note – there are a variety of other colors in this grade. The main ones are listed above.
Flexible High Intensity Grade Type 3 Reflective Tape
Flexible High Intensity Type 3 Tape is a flexible, stretchable version of our standard high intensity tape. It only comes in three colors, white, yellow and orange. This tape is designed to be used on traffic cones and road barrels, however, it is also great for a variety of other applications where a bright, stretchable tape is needed. For example, hard hats have an uneven convex surface and most tapes will not conform. But flexible high intensity will.
High intensity type 3 tape is made by laminating layers together. The high index glass beads are contained in little honeycomb chambers with an air space above them. This arrangement makes for a brighter tape. Although still thin, this tape is a little stiffer than engineer grade. It is excellent for smooth surfaces and is about 2.5 times brighter than engineer grade. This tape is used in applications that require a viewer to see the tape from medium distances away. It is more expensive than engineer grade but less expensive than prismatic films. This tape also disperses light in a wide angle. This combined with the tapes increased reflectivity makes it light up quicker to the viewer than other tapes. CAD cutting into letters and shapes is not recommended with high intensity. It is very popular for creating sign backgrounds, wrapping bollards, marking loading docks, making gates reflective and other similar applications. Recommended for applications where the viewer is within 100 yards of the tape or in areas where there is competitive lighting.
White – 250 candelas
Yellow – 170 candelas
Orange – 100 candelas
Green – 45 candelas
Red – 45 candelas
Blue – 20 candelas
Non Metalized Micro-Prismatic Reflective Tape – Type 4 (also known as high intensity prismatic HIP) Oralite 5900
Non Metalized micro-prismatic tape is made by laminating a layer of prismatic film onto a honeycomb grid and white backing. It is similar in construction to high intensity glass bead tape but with the air chamber below the prisms. (air backed micro-prisms) The white backing makes the tape color more vivid. It is a little more expensive than high intensity but less expensive than metalized micro-prismatic. Best if applied to a smooth surface. This film is visible from much farther away than high intensity or engineer grades and is great for applications where the viewer is far away from the tape.
White – 360 candelas
Yellow – 270 candelas
Orange – 145 candelas
Green – 50 candelas
Red – 65 candelas
Blue – 30 candelas
Metalized Micro-Prismatic Reflective Tape – Type 5 – Oralite/Reflexite V82
Metalized micro-prismatic reflective tape is the top of the line when it comes to durability and reflectivity. It is molded into one layer which means you never need to worry about delamination. This is especially good when using the tape in a dynamic environment where it may be abused. You can beat it up and it still reflects. It is made by coating the back of a micro-prismatic layer with a mirror coating and then applying adhesive and a release liner to the back. It is more expensive to make but well worth the effort. Because it is a single layer film it can be CAD cut into letters and shapes. This material can be used for all applications as well as those where the viewer is in excess of 100 yards from the tape. In most cases, this reflective tape can be seen from over 1000 feet away. This makes it excellent for highway applications or applications where the tape will be shining through snow or rain.
White – 750 candelas
Yellow – 525 candelas
Green – 130 candelas
Red – 130 candelas
Blue – 55 candelas
V92 Metalized Prismatic Reflective Tape – (comparable to type 5)
V92 Reflective Tape by Orafol/Reflexite is very similar to V82 only it is a little less expensive and slightly less bright when it reflects.
V98 Conformable Reflective Tape by Orafol/Reflexite – Metalized Prismatic – (comparable to type 5)
V98 is designed for vehicle graphics and is also cuttable on a plotter. I have found it to be the easier to cut than the V82 or V92 films. It is a little thicker and has a slightly more rubbery texture. It reflects at 750 candelas for white. It is very popular for striping emergency and utility vehicles.
Lastly, Reflexite SOLAS reflects at over 1000 candelas. It is available only in white/silver. It has a greyish silver look in the daytime but is bright white at night. It can be seen from over a thousand feet away in good and bad weather conditions.
There are two types of reflective tape, glass bead and prismatic. Glass bead tapes were the first reflective tapes and then in the 1960’s prismatic tape was invented by Reflexite. It is interesting that prismatic tapes have not replaced glass bead tapes. Even after 50 years. This is because both have characteristics that make them desirable in certain situations.
Glass Bead Reflective Tapes
Glass bead tapes use microscopic glass spheres to bend and reflect light back to the light source. Because of the imperfections and curved surfaces in glass beads, tapes made with beads are less reflective than tapes made with prisms. Glass bead tapes are about 30% efficient. This is a disadvantage. However, there are three advantages that glass bead tape has over most prismatic tapes. First, glass bead reflective tapes are much more affordable. This is because they are simpler to manufacture. Second, most glass bead tapes are CAD cuttable meaning that you can cut letters, number and designs out of the tape and create reflective signs or graphics. Third, glass bead tapes reflect light back at wider angles. In other words, glass bead tapes are sort of like flood lamps whereas prismatic tapes are more light spot lights. The diagram below shows this.
As you will notice from the diagram above, the glass bead tape disperses light more than prismatic tape. That is why it is not as bright at farther distances. However, at close distances the wider angle of dispersion can be an advantage. Let say for example that a fireman is wearing a high intensity glass bead tape on his equipment. When someone shines a light towards him the tape will light up for the person with the light and, if you are fairly close, it will light up for you as well. Also, as the beam nears the fireman, his tape lights up quickly. Again, this is because of the dispersion of the light. Many people prefer the high intensity glass bead tape for close up applications. For long distance applications the prismatic is always better. This is because the glass bead tapes completely disappear at a distance of a few hundred yards whereas a prismatic tape is still visible for over a thousand yards or more.
There are two basic types of glass bead reflective tapes. The first is a standard engineer grade or type 1 tape. White engineer grade tape reflects at about 75 candlepower. This is the most popular tape and is found on car tags, stop signs, speed limit signs, emergency vehicle striping and graphics, etc.. The second type is high intensity or type 3 tape. This tape has higher index beads and encapsulates them in a honeycomb pattern. White high intensity tape reflects at about 250 candlepower. You will find this type of tape on traffic cones and road barrels.
Prismatic Reflective Tape
Prismatic is more efficient and returns about 80% of the light sent to it. Therefore it is brighter than glass bead tapes. Prismatic tape reflects light via man made prisms. Since the mirrors are flat and not curved they are more efficient. The light sent from the tape is more focused and can therefore travel farther still be seen. For long distance applications like DOT regulated trucks or coast guard search and rescue a prismatic tape is a must. There are several grades of prismatic tape starting with a type 4 and going up to a type 8. Because they are all so bright, to the human eye there is very little noticeable difference in the various prismatic types. It is when you get far away from the tape that you notice a difference. The farther away you need to see the tape the higher the type needs to be. The brightest tape that I know of is SOLAS coast guard approved tape. It is used for offshore applications and is vital for search and rescue operations where the victim may be a thousand or so yards away.
Many prismatic tapes are too thick to CAD cut. The exception are Reflexite tapes. Reflexite invented prismatic tape make the tape in a thin single layer. This has two advantages. Number one, the tape will not delaminate like the thicker tapes. Number two, it can be CAD cut with a vinyl cutter/plotter. This is a huge advantage. Prismatic graphics show up several times farther than standard glass bead graphics. The advantages of this are obvioius.
Some different types of prismatic tapes are DOT C2 Tape, FRA Railcar Tape, SOLAS coast guard tape, School Bus Tape, Chevron Reflective Striping, and Sign Sheeting.
In summary, both glass bead and prismatic tapes have their purpose and will continue to keep people safe and visible for years to come.
Reflective tape reflects in one of two ways. Either through the use of microscopic glass beads or via man made prisms. Glass bead technology is the oldest and prismatic tapes are more recent.
Note – prismatic reflective tapes were invented by Reflexite Americas in the 60’s.
Glass bead tapes reflect light back less efficiently than prismatics. However, glass bead tape is much less expensive. For applications within a 300 foot range they are fine and sometimes preferable.
Prismatic tape has a tighter more efficient return of light. A brighter, tighter beam extends much further giving prismatic tapes an operating range beyond the thousand foot mark. For marine, highway or traffic applications where long distance conspicuity is important, prismatic is the way to go.
The diagram below shows the dispersant characteristics of each type of tape. Glass bead tape reflects light back sort of like a flood lamp. Up close this is fine. Prismatic tapes shine like a spot light. This is better when the viewer is far away.
What is the difference in brightness? Lets compare the color white/silver. White Glass bead tape reflects at about 75 candelas for the standard engineer grade type 1 tape (like your car tag) and 250 candelas for the high intensity type 3 tape. Prismatic tapes start at around 460 candelas and go up to 1000 candelas for SOLAS tape. As you can see there is a big difference in the two tapes. Each has its function and neither will ever become obsolete.
Metallized versus Non Metallized Micro Prismatic Reflective Tapes
These two types of construction refer to prismatic retro reflective tapes. A prismatic tape uses man made prisms or mirror to reflect light back to the source. (This is different from glass bead tape which uses glass spheres to reflect light.)
Metallized Prismatic Reflective Sheeting
This type of film is created by first creating an array of micro prisms then coating the top of these prisms with clear or colored polymer and metallizing the back of the prisms with a mirror type finish. This process completely protects the prisms so that the tape can be cut in any place without compromising the integrity of the prisms. You can cut letters, shapes, numbers, etc… without having to worry about the prisms becoming contaminated with the elements. This tape often has a pattern on the front which is normally used to make the tape more visible or vivid in the daytime. It is also much thinner than Non Metallized prismatic tapes and because of this can be wrapped around smaller diameter curves. (snow poles, bollards, etc..)
Non Metallized Prismatic Reflective Sheeting
This type of film is often referred to as an air backed prismatic. Non metallized films are made by first creating a prismatic array. This can be clear or colored. This layer is then laminated onto another layer that provides a white background for the top prismatic layer. These films are normally more vivid than metabolized films since they use a white background versus a metallized mirror background. The downside is that the two laters can delaminate. It is also thicker and less flexible. This this type of film is great for signs and other static applications but for vehicle graphics a metallized film is a must.