Neon Light Knot

The term ‘neon’ has become the vernacular for cold cathode lighting, whereby different colours of light are produced by passing current through a range of different gases. The generation of visible light relies on an electric charge being passed between two electrodes at each end of a tube. This causes excitation of the inert gas in the tube, which subsequently emits light energy as the atoms relax. This particular neon 'knot' was made by Neon Workshops during a neon-making workshop at the Institute of Making in 2010. The gas contained within this neon knot is argon, which produces a violet light.

In addition to the various colours generated by the gases themselves, cold cathode lights can have phosphorescent coatings present on the inside of these glass tubes that affect the overall colour. Mercury vapour can be introduced into argon lamps. This has the effect of generating ultraviolet light that excites the coating, which in turn emits visible light as its constituent atoms and molecules relax. Mercury in lamps is currently being phased out by EU directives.