The allegory of the cave is one of the most inspiring readings to get acquainted with design semiotics. In this beautiful metaphor, Socrates discusses with his disciple Glaucon the fundamentals of perception of reality and introduces to him the concepts of archetypes. In this article, I explain how my RCA final project dealt with the same principles to improve the concept of light.

DElight: liquid light


The theory of form

The allegory of the cave is one of the most inspiring readings to get acquainted with design semiotics. In this beautiful metaphor, Socrates discusses with his disciple Glaucon the fundamentals of perception of reality and introduces to him the concepts of archetypes. In the dialogue, Socrates describes human knowledge of the world as the perception of shadows that a group of humans would see projected into a wall. Those humans, locked inside a cave, have those shadows as their only information about the inside world, and as shadows pass by, they began to ascribe forms to them. Those forms represent the knowledge of the material world, and are abstract representations of meanings.

With this metaphor, Plato introduced his Theory of Form. In his mind, all material in the universe has its original "mould”, which determines its existence, shape and behaviour. As humans, our perception of this is like the shadows on the wall: what we perceive is an imperfect, yet recognizable, version of the original mould. When we look at a dog, we know it is a dog because it has some traits that hint to us: it has four legs, a determined size range, a tail, a head. Yet, we are still able to recognize a dog even though it has three legs. Even though some of the "parts" of the dog's mould are not present, our perception allows for a range of variations of those parts, and their sum is our idea of a dog.

In design semiotics, there is a word for that original mould: archetype. Objects, as any other material substance, have their archetype, their abstract essence that allows the human mind to recognize its meaning, its function. A chair has its chair archetype: four legs, a seat, a backrest. A table has four legs and a tabletop. Most of the work done on design is based on exploring, refining and elaborating on those object archetypes.


The archetype of light

As an immaterial substance, though, the archetype of light had to borrow other embodiments over time in order to populate humans’ imagery. First, light meant a fireplace, the sun. Then it became candles, luminaries, gas lighting. Electric lighting inventions in the 20th century gave us our most recent archetypes: the bulb. Nowadays, there are two main archetypes that come up to contemporary minds: the bulb, and the lamp or luminaries, with a base, a wire, a light source and perhaps a shade.

Light, however, is broader that those archetypes. The phenomenon of light has been dominated in the past century by thermal processes: light sources that emitted light because of being heated. From the sun and the stars to incandescent and halogen lamps, without forgetting flames, all of those sources are thermal: they emit light because they are at a given temperature that causes them to emit blackbody radiation, therefore light. There are other ways to generate light though. Luminescent light sources rely on other principles rather than heat: cold body radiation. The world is populated with such examples, especially in the animal world. Recent developments in lighting based also in cold body radiation, such as LEDs, are based on other principles not so close to the popular imagery of a flame, a bulb or a luminary.

New technologies in lighting are pulled by the need of finding a more efficient light source than thermal, since the latter transforms a higher percentage of the energy input into heat that gets dissipated into the atmosphere, and not light. LEDs and OLED sources are finding their way into their industry R&D departments as the alternatives for domestic and professional lighting. However, luminescent sources, as phosphorescence, electroluminescence and fluorescence, are being relegated to minor lighting functions because of their poor performance in light output and their dependence on another light source.

But as it always happens with new inventions, the discovery and exploitation of a technology has a learning curve, and it takes some long time for those new technologies to inform a new generation of archetypes. The same way first cars resembled horse carriages, and first plastic products copied shapes coming from existent metalwork techniques, new lighting technologies have yet to revolutionize lighting. The archetype of the bulb, of the luminary, remains intact in our minds.


Light from chemical reactions

There is a luminescent technology, though, that has a great potential of radically changing this archetype: chemoluminescence. Chemoluminescence is the emission of light as the result of a chemical reaction. In said chemical reaction, two compounds, or reactants, break down when they get in contact with each other, and the resulting molecules rearrange to form different compounds, or products. When that happens, energy is released in the form of light. This extra energy happens mostly because the products have less energy stored in their bonds than the reactants. Unlike any other luminescence technologies, it does not require the presence of an external light source to produce light, and its brightness is significantly higher as standard, and can be regulated by accelerating the chemical reaction - commonly heating up the mixture heightens the light output.

Almost all of us have experienced this phenomenon. Who has not broken one of those glowsticks and realized, amazed, the bright light arising from it? This happens because the plastic tube filled with one of the reactants (a hydrogen peroxide solution) and a fragile crystal flask that contains, in turn, the other reactant (a fluorescent dye and a phenyl oxalate ester). When the stick is bent, the crystal flask breaks, allowing the two reactants to mix and generate the luminescent reaction. Chemoluminescence has great prominence too in criminology techniques; if there is blood, the Luminol will react in an analog way and generate light, speaking out the truth. The lucky ones who have had the chance to see the beautiful sight of dancing fireflies at night have witnessed the biological version of chemoluminescence, bioluminescence.

As illustrated by those examples, chemoluminescence takes the shape of a liquid, since both reactants are often in that state. When observing the raw reaction at a laboratory and not inside a firefly or a glowstick, what the observer will appreciate is, plain and simple, liquid light. I did explore, in my graduate project (De)light* at the Royal College of Art, the huge potential of liquid light and its meaning – if you’re interested, you can find more details, the research thesis and multimedia material at, or clicking here. What I researched and explicated with my project is that liquid light is a beautiful, revolutionary, change of the light archetype. It represents a step towards what would become a significant change in the concept of domestic lighting. And what I would like to share with you here is a brief summary of my project and its intentions.


DElight: liquid light


Light freed from its container

The poetic and practical potential of having light without the need of a solid source is hugely appealing. Practically, liquid light frees light from the necessity of being tied up to the electric grid. Light could be brought off-grid to those places without the wiring infrastructure. No electrical input would be required to make it work, reducing the cost and environmental impact of lighting. Poetically, it could mean rivers flowing along the streets to form urban lighting. It could mean buildings in which light comes from cascades. It could mean pouring, containing, reshaping light, as you would do with any other liquid. By freeing it from its physical container – the bulb –, light returns to its primary significance, that of an element which appears magical, intangible and liberated. Liquid light enriches the experience of light, allowing the user to enjoy it directly and allowing for new lighting scenarios to populate our imagery. New archetypes, new forms, would liberate us from the shadows projected on the cavern and make a step ahead in the semiotics of light, thus leading a new perceptual revolution.

Of course, there are currently technological impediments to the use of chemoluminescence as a professional light source. As in any other chemical reaction, it finishes when the reactants are used up. In its current state, the chemical compounds are not totally safe for common use. And the emanating light is often dull and unnatural. The question here though is whether all those technical limitations are there because chemoluminescence has only been developed to suit non-common uses. If the potential value of this technology strikes the R&D departments of companies, development efforts will be aimed at providing this light source, and researching into creating compounds that answer those three limitations from a user point of view. Attention needs to be drawn not into improving existent archetypes, but radically change them.


You see things as they are and ask, “Why?”

I dream things as they never were and ask, “Why not?”

George Bernard Shaw



Let your imagination flow

One of the objectives of my project  was to trigger development efforts with new approaches in  chemoluminescence. If there’s anything to that regard you’d like to  comment or share, please feel free to do so.

What would you like to do with liquid light?


Further reading: Pour me a glass of light on Yanko Design.

I did originally post this article on the Light Community blog here, but you know, old but gold... 

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