Fluorescent Materials:

Fluorescence is where a material absorbs light at one wavelength and re-emits it at a longer wavelength, typically visible light. This process occurs instantly, creating a vibrant colourful glow.

Characteristics of Fluorescent Materials:

1. Instant Emission: Fluorescent materials emit light as soon as they absorb energy, resulting in an immediate and vivid glow.

2. External Light Source Required: Fluorescent materials rely on an external light source to activate their fluorescence. Once the external light is removed, the emission stops.

3. Limited Duration: The glow from fluorescent materials is temporary and lasts only as long as the external light source is present.

Photoluminescent Materials:

Photoluminescence is the absorption of light at one wavelength followed by the re-emission of light at a longer wavelength, but with a difference—it occurs after a delay. This delayed emission is what gives photoluminescent materials their characteristic glow in the dark. These materials store light energy when exposed to light and release it gradually when in darkness.

Characteristics of Photoluminescent Materials:

1. Delayed Emission: Photo-luminescent materials have a delayed emission of light, creating a soft and long lasting glow after the removal of the light source.

2. No External Light Required: Unlike fluorescent materials, photoluminescent materials do not need a continuous external light source to maintain their glow. They "charge" in the presence of light and emit light in the absence of it.

3. Extended Glow Duration: Photoluminescent materials can continue to emit light for an extended period, gradually fading over time as the stored energy is depleted.

Applications:

• Fluorescent Materials: Used for creating vibrant and dynamic colourful effects in artwork. Fluorescent materials are particularly popular where a bright and immediate burst of colour is desired.

• Photoluminescent Materials: Used in Glow in the dark products. Their ability to glow in low-light conditions without the need for external power makes them perfect for star ceilings and murals at night. 

   

  Glow in the dark paint does not fluoresce under UV light; instead, it absorbs and stores energy for later emission in the dark.
  
  Fluorescent paint has an immediate and vibrant response to UV light.