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n the previous article, we discussed how to select the brightest photoluminescent powder from multiple dimensions. However, does a product made with the brightest powder necessarily have the highest brightness? The answer is not necessarily. This article will explain in detail how, as a product designer, developer, or factory procurement staff, you can choose the most suitable photoluminescent powder for your product.
The selection process mainly involves three steps:
First, consider the particle size, which determines whether it can meet the product requirements and production process. After that thinking about the luminescence features, selecting the one that suits the product application scenario (charging speed, initial brightness, and afterglow duration). Finally, choose the color (body color and luminous color).

How does the production process affect the choice of particle size?

For example, in スクリーン印刷, the particle size of the photoluminescent powder must be smaller than the mesh size to ensure all the luminescent ink can pass through. Similarly, when spraying paint, the particle size of the photoluminescent powder must be smaller than the nozzle diameter of the spray gun, otherwise it will clog the nozzle. When making 極薄コーティング or ultra-fine cables, the maximum particle size of the photoluminescent powder must be smaller than the coating thickness or cable diameter. Therefore, when choosing the particle size of the photoluminescent powder, it is crucial to understand the production process.

different partical size

Even If The Particle Size Fits The Process Requirements, Larger Particles Do Not Always Perform Better.

The characteristic of photoluminescent powder is that the larger the particle size, the higher the brightness. However, when choosing photoluminescent powder, choosing larger particle sizes doesn’t always lead to better brightness. A key concept here is the coverage. Larger particles have higher brightness, but their coverage is not as good as that of smaller ones. When applied to products,

Sometimes smaller particle powder performs better. The final product may show a more translucent and even brighter effect . Professional suppliers have more experience in finding this balance.
Some customers want to choose large particles and grind them according to their needs. It is important to note that it is not feasible because the grinding process will damage the surface of the photoluminescent powder particles, causing them to lose their luminescent effect. Therefore, you can only choose according to the existing particle sizes.

Step 2: Different products require different luminescent features.

The features of luminescent powder vary due to different formulations. These properties include charging speed, initial brightness, afterglow duration, and sensitivity to low illumination.

  • Charging Speed: This reflects the efficiency of the photoluminescent powder in absorbing light energy. It describes how quickly the powder can be excited to emit light. The faster the charging speed, the higher the initial brightness. (Consider linking to a comparison video between YS and HS)
  • Initial Brightness: This refers to the brightness level of the photoluminescent powder in the first few seconds after the light is turned off. The initial brightness is directly proportional to the charging speed.
  • Afterglow Duration: The afterglow duration indicates how long the photoluminescent powder emits light. According to the international standard DIN67510, the afterglow duration is measured by exposing the powder to a D65 light source at 1000 lux for 5 minutes in a completely dark lab, then turning off the light and recording the brightness at the 10th minute. Higher data values mean longer glowing times.
  • Sensitivity to Low Illunimation: This measures the powder’s ability to glow under low-intensity light sources. If the powder can still emit light when exposed to very low light, it is considered sensitive to low illunimation.

Different products require different combinations of these features. For example:

  • Toys: For example, photoluminescent water bullets need to be illuminated within 0.1 seconds and do not need to glow for a long time after being shot. This application requires fast charging speed and high initial brightness, but does not need a long afterglow duration. (Consider linking to a relevant product video)
  • Safety Signs: For safety signs in building, it is crucial that they glow for as long as possible during a disaster to provide more time for people to escape. This application requires a long afterglow duration but does not emphasize charging speed or initial brightness.
  • Combined Requirements: Some products require both comparatively fast charging and a reasonable afterglow duration. In such cases, professional manufacturers need to adjust the formulation to balance these properties.

Step 3: Different Colors of Glow Powder

The color of glow in the dark powder comes in three series: Nature Colors, Dyed Colors, and Orange-Red Colors. Many customers think they can choose any color of photoluminescent powder at will, but different colors have different properties and are not entirely interchangeable. They are suitable for different product applications.

  • Nature Colors: This series includes yellow-green, blue-green, and sky blue. They are naturally produced, with different formulas emitting different glowing colors. The characteristic of this series is that their body color in daytime is all yellowish-white to pale-white. They have the highest luminescence among all the 3 series. In terms of brightness, yellow-green > blue-green > sky blue. They are mainly used in products that require high brightness and long afterglow duration, but do not need colorful body colors. For plastic products, only yellow-green and sky blue are suitable. Blue-green photoluminescent powder has harder particles, which can result in dark finished products.
  • Dyed Colors: These are usually made by physically mixing nature color powder with different fluorescent powders. The characteristic of this series is that they have various body color in daytime. Their brightness is relatively weak because the fluorescent powder covers part of the glow brightness. They are mainly used in products that need to be colorful during the day but do not require high brightness or long glowing time in the dark, such as T-shirt patterns, decorative paintings, arts etc.
  • Orange-Red Colors: This series has the lowest brightness and the shortest glowing time only around 10-20 munites. Due to the complicated formula and production, also the higher cost of raw material, it is around 4-5 times more expensive than the above two. Typically, only high-priced products that pursue uniqueness, such as artworks and jewelry, will consider Orange-Red Colors.

Customers can also purchase only the nature color photoluminescent powder and add dye colorants during production to create their own colors. It is important to note that the proportion of dye added should be as small as possible and preferably light colors to retain more of the luminescent effect.

How to achieve the best luminescent effect?

How to achieve the best luminescent effect in the final product does not have a standard answer. It is gereally related with getting the most suitable luminescent powder, and the production. The powder’s types, machinery, product material, all of them may affect the final result. Therefore, the most effective approach is to choose an experienced supplier and actively conduct experiments.
An experienced supplier understand the nuances of different photoluminescent powders and their interactions with various manufacturing processes. They can provide valuable insights and recommendations based on their expertise. During experiments, they are able to optimize the luminescent properties of the product by providing technical guidance and making adjustments based on the different phenomena that occur. Their knowledge helps optimize the luminescent performance of your product.
Collaborating with a knowledgeable supplier and continuously experimenting ensures that the final product will meet the best luminescent effect.