Reflective Tape Comparison - Brightness in Candelas
Retro-reflective tapes come in various types, each designed for specific purposes. Their adhesion, flexibility, conformability, and brightness differ based on the brand and type. This article analyzes the photometrics of various tapes by measuring their reflectivity using a "retro-reflectometer" (pictured above). This instrument measures the amount of light returned by a reflective film at different angles. In our study, reflectivity is measured at 0-degree and 30-degree angles to assess how well the tape reflects light when struck perpendicularly and at an angle, simulating what a vehicle driver would see.
Similar to a flashlight, the higher the candela reading from a section of retroreflective tape, the farther away it can be seen. In traffic, reflective tapes that are visible from a greater distance provide earlier warnings to drivers, giving them more time to react.
Definitions:
Candelas / Lux / Square Meter – A unit of luminous intensity expressed as one candela in one second of light emittance per square meter of area. This is the unit of measurement used to measure the intensity of brightness of retroreflective sheeting and other lighting. This measurement is also used to set minimum standards for reflectivity.
Entrance Angle – The angle between the illumination axis and the retroreflector axis. This is the angle at which light enters a retro-reflective film. At a perpendicular 0-degree angle, reflectivity is at its highest. Specification sheets measure maximum reflectivity at a 4-degree entrance angle. At a 15-degree entrance angle, retro reflectivity is often reduced by approximately 20%. At 30 degrees, reflectivity often drops by approximately 50%. At 45 degrees, reflectivity often drops by approximately 85%. And at a 60-degree entrance angle, retro reflectivity is often reduced by 86–99% depending on the tape type and brand.
(Note - Our readings are for comparison purposes only; readings differ with various retroreflectometers. Our tests are for comparison purposes only.)
Study Results - Table:
| Reflective Tape Name & Type | 0 Degree | 30 Degree | % diff - 0 to 30 |
| Nikkalite Flexible Engineer Type 1 | 86.0 | 43.4 | 49.5% Decrease |
| Oralite 5650 RA Engineer Type 1 | 81.0 | 49.8 | 38.2% Decrease |
| 3M 680 CR Engineer Type 1 | 63.0 | 27.9 | 55.5% Decrease |
| Nikkalite Super Engineer Type 2 | 166.7 | 76.7 | 53.9% Decrease |
| Nikkalite High Intensity Type 3 | 222.8 | 241.7 | 8.5% Increase |
| Nikkalite Flex Hi Intensity Type 3 | 245.4 | 256.8 | 4.8% Increase |
| 3M 3930 HIM Prismatic Type 4 | 574.5 | 368.2 | 35.8% Decrease |
| Avery HIP Prismatic Type 4 | 449.2 | 143.5 | 68.1% Decrease |
| Nikkalite HIM Prismatic Type 4 | 629.8 | 454.8 | 27.8% Decrease |
| Oralite 5900 HIP Prismatic Type 4 | 653.8 | 313.9 | 52.0% Decrease |
| Oralite 5930 Prismatic Type 4 | 415.9 | 170.0 | 59.1% Decrease |
| Oralite 5934 Prismatic Type 4 | 691.1 | 269.1 | 61.0% Decrease |
| Oralite V82 Metalized Prismatic Type 5 | 1070.9 | 583.3 | 45.5% Decrease |
| 3M 4000 DG3 Prismatic Type 11 | 628.4 | 161/305* | 74.3/51.4% Dec. |
| Avery 11500 Omnicube Type 11 | 621.2 | 150/165* | 75.8/73.4% Dec. |
| Oralite 9000 Prismatic Type11 | 749.8 | 407.9 | 45.6% Decrease |
| 3M 983 Diamond Grade | 797.7 | 487.8 | 38.9% Decrease |
| 3M 983 DOT C2 Truck Tape | 786.7 | 542.3 | 31.0% Decrease |
| 3M 983 FRA Tape | 789.6 | 548.9 | 30.4% Decrease |
| 3M RGA Rail Gate Arm Tape | 648.1 | 339.9 | 47.5% Decrease |
| Oralite V98 Vehicle Conspicuity | 627.1 | 322.5 | 48.6% Decrease |
| Oralite V92 Vehicle Conspicuity | 629.3 | 317.3 | 49.6% Decrease |
| Oralite V92 DOT C2 Truck Tape | 635.8 | 300.7 | 52.8% Decrease |
| Oralite V82 Type 5 DOT C2 | 823.1 | 354.1 | 56.9% Decrease |
| Oralite FRA Rail Car Tape | 789.6 | 403.1 | 48.9% Decrease |
| Oralite RGA Rail Gate Arm Tape | 828.5 | 378.0 | 54.3% Decrease |
| Oralite Marine SOLAS Tape | 1078.0 | 476.4 | 55.8% Decrease |
| Oralite Photo Electric | 1407.8 | 771.1 | 45.2% Decrease |
Study Results - Images:
Engineer Grade Retro Reflective Tapes - Type 1 (Oralite, 3M™, Nikkalite):
We tested three brands of engineer-grade type 1 reflective tapes. Of the three, Nikkalite ELG Flexible Engineer Grade, the least expensive, rated the highest for a 0-degree entrance angle. Oralite's 5650 Rapid Air scored the second-highest candela rating and the highest for a 30-degree angle. 3M™ 680 CR, the most expensive of the three films, had the lowest candela readings at both 0 and 30-degree entrance angles. All three films are high quality with long outdoor lifespans. (Note: We plan on sampling 3M 680 CR again using a different sample to verify our reading.)
Super Engineer Grade Glass Bead Tape - Type 2 (Nikkalite)
To the best of our knowledge, there is only one Super Engineer Grade film sold in the United States. It is advertised to be twice as bright as standard engineer grade with the same basic characteristics. It accomplishes this by using higher index glass beads. Our retro-reflectometer readings verify that Super Engineer Grade is about twice as bright as an average engineer grade type 1 with the same look and feel. It is easily plotter cut and printable, and for all practical purposes, double the brightness means the film can be seen from double the distance.
High Intensity Type 3 Glass Bead (Nikkalite)
We tested this film for reflectivity and got readings of 222 candelas for standard high intensity and 245 for the flexible version. This was expected. What was surprising was that when the entrance angle increased from 0 to 30 degrees, the tapes reflected better by 4-8%. Out of all the tapes we tested, only this tape does that. Generally, reflective tapes lose 50% of their brightness when the entrance angle increases from 0 to 30 degrees, but Nikkalite high intensity type 3 actually gets brighter.
To explain, Type 3 glass bead tapes encapsulate high-index glass beads in individual cells. When in this array, the beads form a dome under the transparent colored top coat. Because of the dome shape, the tape reflects at an angle as well as perpendicularly, and in this case, slightly better. With candela readings of around 250, Type 3 tapes can be seen from greater distances than type 1 or 2.
High Intensity Prismatic -Type 4 (3M , Avery , Oralite , Nikkalite)
High Intensity Type 4 Prismatic Tapes have effectively replaced Type 3 glass bead films for road signs and similar applications. Type 4 is much brighter and more rugged in its construction. We tested four brands of HIP, one each for 3M, Avery, and Nikkalite, and three for Oralite.
3M 3930 High Intensity Prismatic is the most popular film for signs in the states and is used mostly for road signs. It reflects at wide angles with only a 35.8% decrease in reflectivity at a 30-degree angle. While not the brightest of the Type 4 films we tested, it is plenty reflective and is the second brightest at a 30-degree angle.
Avery HIP, while plenty bright, tested the second lowest at a 0-degree angle and the lowest at a 30-degree angle.
Nikkalite HIM films had the highest readings for a 30-degree angle, and the second highest for a 0-degree angle.
Orafol makes several Oralite Type 4 films for various applications. We tested three of these films: 5900, 5930, and 5935. Their 5900 and 5935 films had the two highest candela readings for all the Type 4 films at a 0-degree entrance angle. Oralite 5930 reflective tape, which is for work zones, came in at about the same as Avery.
Type 5 Prismatic Reflective Tapes (Oralite)
We tested Oralite's V82 Type 5 prismatic metalized reflective tape and were impressed by its reflectivity at both a 0-degree and 30-degree entrance angle. With candela readings of 1070 and 538 respectively, V82 is an unbelievably bright film. This film is made using Oralite's AP1000 sheeting. It is very thin and flexible. However, it does not stretch or conform, so it is suitable for flat or singular curved surfaces like bollards. Oralite V82 and its sister film Oralite SOLAS have the greatest sight distance of any film we have seen.
Type 11 retro reflective sheeting is the latest improvement in retro reflective technology. It is designed for overhead highway signs but can be used for various other applications. Some brands use full cube corner prisms, and some use deep standard cube corner prismatic arrays. We tested 3M, Avery, and Oralite.
3M DG3 4000 series tested at 628.4 candelas at a 0-degree angle. Since it uses full cube prisms, angled reflectivity is higher at one angle and lower at another. The direction you apply the film affects brightness at angles. If measured with the trough-shaped prisms oriented sideways, the 30-degree reflectivity is 628.4. When measured with the prisms going up and down, the 30-degree reflectivity is 305.7. This provides a material orientation choice to best suit your application.
We also tested the Avery 11500 series Omni Cube material. For this film, Avery orients the prism arrays so that 50% are horizontal and 50% are vertical, eliminating the change in reflectivity from orientation. The downside is that both orientations come in on the low side. At a 0-degree angle, the film reflects at 621.2 candelas. At a 30-degree angle, vertical or horizontal, the film reflects between 150 and 165 candelas.
| Reflective Tape Name & Type | 0 Degree | 30 Degree | % diff - 0 to 30 |
| 3M 983 Diamond Grade | 797.7 | 487.8 | 38.9% Decrease |
| 3M 983 DOT C2 Truck Tape | 786.7 | 542.3 | 31.0% Decrease |
| 3M 983 FRA Tape | 789.6 | 548.9 | 30.4% Decrease |
| 3M RGA Rail Gate Arm Tape | 648.1 | 339.9 | 47.5% Decrease |
| Oralite V98 Vehicle Conspicuity | 627.1 | 322.5 | 48.6% Decrease |
| Oralite V92 Vehicle Conspicuity | 629.3 | 317.3 | 49.6% Decrease |
| Oralite V92 DOT C2 Truck Tape | 635.8 | 300.7 | 52.8% Decrease |
| Oralite V82 Type 5 DOT C2 | 823.1 | 354.1 | 56.9% Decrease |
| Oralite FRA Rail Car Tape | 789.6 | 403.1 | 48.9% Decrease |
| Oralite RGA Rail Gate Arm Tape | 828.5 | 378.0 | 54.3% Decrease |
| Oralite Marine SOLAS Tape | 1078.0 | 476.4 | 55.8% Decrease |
| Oralite Photo Electric | 1407.8 | 771.1 | 45.2% Decrease |
