My research in the area of “inherent illumination” represents a branch of material science uniquely focussed on the interplay of materials being both functional and a source of their own light and colour. To achieve functionalities such as surface coatings, paints and inks, pigments needed to be developed that were considerably below the current conventional size range – that is in the realm of nanotechnology. To provide self-illumination, new photon physics of phosphorescence had to be researched and developed at this nano-scale. This work was undertaken at the Royal Melbourne Institute of Technology - School of Applied Science 2008-2013 as Professor of Chemistry and Dean of Research – College of Science, Engineering and Technology with external Australian Research Council Linkage Grant of about $210,000 and participation of a local industrial manufacturing partner.
Context of Research
The key research outcome was provision of significantly improved safety and security systems, that is, way-finding coatings and signs in emergency without recourse to power supplies i.e large buildings, stadiums, theatres, and stations. This needed significant improvements in glow persistence, brightness and particle fineness. Arising from this research, new ranges of long glow-persistence pigments have developed that are being put into enhanced safety and security products. Additionally, the work has been published in international material science journals.
Through participation in the RMIT Design Research Institute (DRI) further opportunities arose to explore these pigments in the context novel architecture – Passive Urban Lighting and new approaches to the art of Tapestry since we had now created fibres incorporating these persistent phosphorescent nano-pigment particles. Collaboration with the Tapestry of Light project thus began.
Additionally, the three application areas (Safety & Security, Passive Lighting ant Tapestry Art) provides a avenue to explore the relationships between the particular sensory stimulus of light and colour and the perceived qualities of Art where the artefact itself is the sole source of illumination.
Science is spectral analysis [while] Art is light, wrote Karl Kraus a foremost German language satirist from last century. The underlying photon physics of persistent phosphorescence is illustrated below in terms of light (sunlight) absorbed , stored in excited electron levels, and remitted over prolonged periods.
If electron energy states are altered by doping with an additional neighbouring atom, then electrons can be retained in their most excited states and allowed to only slowly degenerate to a lower intermediate energy level. This produces phosphorescent light emission able to persist for up to 8 hours.
Patrick Hunt points out that it was Abbe Sugar in the 12th century who first exemplified light in terms of: lux, lumen and illumination, terms which today now represent the major technological parameters of light and colour intensity. Visual perception, being largely governed by retinal illuminance is governed by the brightness level of an object in comparison to its total background and thus is a highly differential phenomenon. Light intensity gathered by the eye from illumination sources represents a solid cone as part of a total illuminated sphere growing in size but decreasing in the illumination flux density per unit area, as distance from the source increases as illustrated in the figure below
Advances in the psychophysics of perception have now provided a new avenue to explore the relationships between the particular sensory stimulus of light and colour and the perceived qualities of art. Faber Birren in Leonardo points out that the perception of colour in art was attributed “beyond the eye into the brain” by the 19th century German scientist von Helmholtz and in doing so coined “Perceptionism” as a possible new art form that “continues beyond the eye, up the optic nerve and into the brain (where) it is less concerned with what the eye sees literally than with the way the brain interprets what is seen”.
Our perception of light’s colour and intensity is thus first moderated by the eye’s anatomy with its two types of receptor cells each responding differently to daylight and low light intensities. From which the brain interprets colour and generates, for example, such effects as the significant spectral shift to blue at night (moonlight) and the perceived fading of red-yellow objects faster than blue-green objects (Purkinje’s effect). More recently cognitive neurobiologists such as Dale Purves et al. have clarified perceptual phenomena showing that they depend on spatial attributes of the optical stimulus of an object in the context of past experience. Recasting Mark Weiser’s remarks to the realm of the science achieving tapestries of light “The most profound technologies are those that disappear. They weave themselves into the fabric of everyday life until they are indistinguishable from it.