Photoluminescent Product Range | Vinyl |Sheet / Board | Tape | Floormarkers | Experts in Photoluminescence

Our technical expertise is second to none for all things glow in the dark or adhesive and adhesive tape applications. Our innovative research programme resulted in a Government award. We continue to (quietly!) work on new projects that are both novel and inventive which means that we have the expertise on hand to be able to confidently answer and address all your questions about photoluminescent products

Photoluminescence – what is it?

Photoluminescence (glow in the dark) is the phenomenon by which lightwaves are absorbed by a substance and re-emitted at a lower frequency. The lower frequency may be part of the visible spectrum of light, or, in other words, the human eye can perceive the re-emitted light as a distinct colour.

The scientific basis by which photoluminescence works is phosphorescence and it is that principle that Kemco investigates, develops and uses to assist safety in hazardous environments.

In the process of phosphorescence, a substance is excited by packets of energy contained within light which is a form of electromagnetic radiation. These energy packets are called photons. The energy contained in the photons causes a reversible change to occur within the stimulated substance, in this case a photoluminescent pigment. The pigment most commonly used in Kemco products is a non-radioactive, non-hazardous mixture of the compound strontium aluminate whose effect is enhanced or altered by the addition of differing rare earth compounds.

When the pigment absorbs photons of light, energy is provided which causes transitions to occur within the pigments’ atoms by a process known as intersystem crossing. The energy absorbed is then gradually released back into the surrounding environment (like a slowly leaking reservoir) and this is the energy which the human eye can see in the form of a coloured glow. The slow but steady release of light is termed ‘afterglow’ and explains why photoluminescent materials continue to emit a visible colour for several hours after the removal of the exciting light source.

Photoluminescent pigments are rapidly ‘re-charged’ following exposure to common light sources (e.g. daylight or fluorescent tube light) and as the exciting source is removed (for example when the light is switched off) so begins the process of energy release and afterglow. The time taken to fully re-charge the pigments depends on many factors including the intensity and wavelength of the light source. Practically speaking, this means the initial brightness and the length of afterglow of a photoluminescent material vary according to the intensity and type of the charging light source.

The pigments are able to undergo virtually unlimited cycles of charge/discharge when contained within a suitable matrix as the potential to do this is contained within the individual molecules of the activated photoluminescent pigment.

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