The luminescence principle of fluorescent ink is to store the light energy under illumination and convert it into internal energy, and then convert it into light energy through photochemical reaction and emit it. Generally speaking, the emitted light after absorbing light energy can be divided into phosphorescence and fluorescence. Although both have similar luminescent effects in the environment, they have significant differences. Phosphorescent materials need to be in the dark environment to emit light after absorbing light energy, while the fluorescence emitted by fluorescent ink requires the presence of light to emit light.

In terms of ink display, the color of ordinary ink is presented by the color of reflected light, and the color of absorbed light determines the color of reflected light. However, the color presentation effect of fluorescent ink is significantly different from that of ordinary ink. It can not only output light of different wavelengths but also light of different intensities. For example, the color of fluorescent ink itself is blue, which can absorb the energy of red, blue, purple and other light in the light and convert them into blue wavelength light to emit. This effect makes the object printed with fluorescent ink not only reflect light but also emit light like a radiation source.

From a physical point of view, fluorescent ink integrates light of different wavelengths, converts them, and then overlays and emits them, creating a fluorescent color different from reflected light.