Know Before You Glow!
5 Things You Should Know about Glow in the Dark Materials!
Want to add glow to your designs? Thanks to new technologies, there are now more ways than ever to do that! With so many materials to choose from, it’s easy to become a bit confused over glow in the dark alternatives. Here are some basics!
1. Glow Materials Charge by Absorbing Light
All glow in the dark (photoluminescent) materials work by absorbing light through various sources such as UV or daylight, black lights and regular room lights such as fluorescent or incandescent light bulbs.
After absorbing sufficient amounts of light energy, glow in the dark materials then “re-radiate” the light. So if glow materials are kept in a dark closet without light for a couple of days, the product will need fresh exposure to a light source in order to renew the glow.
As photoluminescent materials are powered by exposure to light, they do not require batteries or bulbs and are endlessly rechargeable. High performance material can glow for many hours until recharged again.
2. Glow in the Dark Materials are Best Viewed in Full Darkness
It may seem obvious but “glow in the dark,” means just that. Glow products are most visible in complete darkness without other competing lights around them. This means that glow materials may work extremely well in a dark campground or along an unlit country road but would not be as visible in a public area illuminated by safety lighting.
A simple explanation is that photoluminescence works by absorbing then emitting light. While in well-lit settings, the materials are absorbing light energy instead of emitting much light. It typically appears to do one or the other whatever is dominant: darkness to emit light or lighting to recharge.
It is important to note that photoluminescent materials are best seen with dark adjusted eyes. This is like walking into a movie theater after the film has started where you must wait a few minutes to literally see your way to your seats. Photoluminescence is the same. It is most visible in the dark when your eyes have already adjusted to night vision.
3. The Relationship Between Glow Intensity and Duration
New high performance glow materials offer excellent brightness and strong longevity of glow. It is important to understand the attributes of the glow intensity vs. the length of time the material actually glows.
The initial afterglow effect is the brightest and most visible in the first 1-3 hours, and then levels off to a moderate level of brightness. As the glow slowly fades, it becomes more of a light white color that is still quite visible in darkened conditions.
In some scientific tests, glow is measured for many more hours of visibility and can reach performance standards of glowing for up to 30 hours. In this type of laboratory test, scientific instruments (vs. human eyes) measure glow output results.
With safety signage, tests are done with human vision and measure the actual visibility of the photoluminescent sign in darkened conditions at 50-100 feet.
Technically, the length of time a glow material is said to “glow” is defined as the amount of time it takes for the afterglow brightness to diminish to 0.32 mcd (0.32 mcd is 100 times the human visible perception limit). Even at this level, the glow is clearly visible in darkness.
Glow output at 10 hours is not nearly as bright as it is at 10 minutes after light exposure. However you can still plainly see it in darkness. So we prefer to say our glow products are visible from “dusk to dawn” based on real life applications.
4. Many Formats of Glow Materials are now Available
Much has changed since the original glow in the dark ceiling stars many of us remember from our childhood. Older forms of photoluminescence had a short glow period and offered weak glow output. Advances in technology have enabled new high performance materials to be developed. This new technology is being integrated into many new substrates that serve as carriers for the glow technology.
Photoluminescent materials can include resin, paints, silkscreen inks, tiles, glow sheets, fabrics, glow crystals and glowing trims such as Lunabrite rope or ribbon.
The wide assortment of materials offers a multitude of choices to suit your project requirements.
5. Color, Size and Distance Impact Glow Perception
In choosing colors, it is important to recognize that glow color affects light output and performance. Green is the brightest and this is why it is used for safety applications. Blue and Blue Green also offer good visibility. Special glow colors like Purple, Reds and Oranges are good for creative effects but offer less apparent brightness and glow duration.
Larger areas of glow will also provide brighter effects. For example, large swaths of glow will stand out more than small or thin areas. Larger areas of glow will also be more visible from a greater distance away.
If your project calls for a smaller scale part or accent area with glow enhancement, you may need more help to maximize the glow output. Glow strength can be customized to maximize brightness and provide longer duration. Our technical experts can create a custom formula that will boost bright effects even for these areas.
Understanding glow properties can make a big difference in selecting materials for your next project.
So now that you know, go ahead and glow!