Sanpo-yoshi Communication
Sanpo-yoshi Communication
President's Column] We contribute to our customers' sales increase in both BtoB and BtoC.
The other day, I worked on a product that used phosphorescent ink. Phosphorescent ink is a type of ink that stores the energy from ultraviolet light—such as sunlight or fluorescent lighting—and glows for a certain period of time in the dark. However, a problem arose.
Sales Rep A"The phosphorescent ink isn't glowing. Could you take a look at it?"
Hiraki"The phosphorescent ink isn't glowing?"
I immediately checked them in a dark place. The sample stickers I’d made before glowed in the dark, but the ones I made this time only glowed faintly…
Sales Rep A"Why?"
Hiraki"I wonder why…???"
This is my first time, too, so I have absolutely no idea.
At times like this, I become a detective. First, I examine the scene.
Hiraki"What's different between the last time and this time with the phosphorescent ink?" ← First, let's identify the changes.
Field Worker B"I made the initial sample a year ago, so I asked the person who worked on it back then and mixed the varnish and phosphorescent agent in a 10:4 ratio. I thought the glow was too faint, so I applied a thick coat, but it didn't make much of a difference."
Hiraki"I see—so you mix a phosphorescent agent into the varnish. But why doesn't it glow even when applied thickly?"
Hiraki"Why don't you try adding more phosphorescent material?" ← I'm guessing it will glow if you increase the amount.
Field Worker Mr. B-yama"We're out of phosphorescent pigment. If you mix in too much, the ink will harden and clog the screen."
Hiraki"Seriously?"
Mr. C, the worker from the previous session"Since you don't want to mix it too much, I mixed about this much last time, too."
Hiraki"So it's the same as last time... (>_<)"
From here on, it’s up to the Forensic Science Laboratory. We’ll conduct tests based on our hypothesis. If the cause lies in something other than the amount of phosphor…
[Hypothesis 1] It doesn't glow right now, but it will glow once it has been exposed to light for a longer period of time.
[Hypothesis 2] Since the sample made a year ago has a thinner coating, the thinner coating is the one that glows in the dark.
Verification Test: Let's Begin!
Test: We will expose the printed materials listed below (①–③) to sunlight for an entire day and examine how well they retain their luster.
① A sample I created earlier
② The items printed with a thick layer this time
③ This time, we printed it with a light ink layer
As a result,
① Shines brightly
② The light is dim…
③ The light is dim…
The test results showed that only ① glowed, while ② and ③ emitted a faint light of similar intensity. Furthermore, extending the exposure time yielded the same results. Increasing the amount of ink did not change the brightness. This suggests that the phosphorescent agent on the surface absorbs the light, preventing it from reaching deeper layers. In other words, the mechanism appears to be that light accumulates in the phosphorescent agent on the surface, causing it to glow. If that is the case, isn’t the amount of phosphorescent agent on the surface simply insufficient?
Regretting that I should have checked right from the start, I called the manufacturer’s phone number listed on the container of the phosphorescent agent.
Hiraki"Thank you for your continued support. I have a question. What is the typical ratio of varnish to phosphorescent agent?"
Manufacturer Representative"It's 1:1."
Hiraki"No way!! I wasn't using nearly enough of the mixture..." ← It turned out I was using significantly more than the amount I had been using on site.
Even though I knew human memory isn’t always reliable, I ordered some additional phosphorescent material, adjusted the formula, and when I printed it, it glowed just fine.
At first glance, it seemed like a detour, but I came to an important realization. Although I had imagined that a thicker layer would be more effective, the way it shimmers doesn’t change even with a thin layer. In other words, I can offer this at a lower price than I had anticipated for a thick layer! I felt like I’d come out ahead, thinking to myself, “Everything in life is a matter of perspective.”
I think phosphorescent ink—which absorbs light and glows in the dark—can be quite interesting depending on how it's used.
・A design that is visible only in dark places
・A design with different patterns for day and night
・To be used in the hidden illustration section
I get excited just thinking about all these possibilities.
Thanks to the customer who placed the order and the worker who made a mistake with the formula, it turned out to be a valuable experience. I’m grateful (＾－＾)