As it happens, rubies are one of Dr Subramanian's inspirations.
His hope is that by piggybacking on the structure of their crystals—
already known to yield an appropriately, well, ruby, colour—he might be able to reproduce the effect.
A weakness of this approach is that rubies themselves make an unsatisfactory pigment. When crushed, they become pale pink.
A second avenue may be more promising. Many inorganic reds, including those based on cadmium, lead and mercury, are semiconductors.
Dr Subramanian and his team hope to use tin—a metal in the same group of the periodic table as lead—
to produce a similarly vibrant, though non-toxic, semiconductor pigment.
Inevitably, the semiconductor approach does bring problems of its own.
A semiconductor's colour depends on a phenomenon called its band gap. This is the ease with which its atoms can shed electrons.
The process of shedding requires energy, often in the form of light,
so a substance's band gap helps determine which frequencies of light it absorbs and which it reflects.
Unfortunately, band gaps can, themselves, be altered by exposure to energy in the form of heat or light. That changes the pigment's colour.
For example, mercury sulphide, known to painters as vermilion, has a small band gap.
This means it absorbs much of the visible spectrum, reflecting only red because red light is insufficiently energetic to shift the relevant electrons.
If the gap is diminished still more, as sometimes happens when vermilion is exposed to light,
the pigment absorbs all visible light and turns black. Making a semiconducting red is not enough, then.
It also needs to stay red when in use. And that essential property remains elusive.
Dr Subramanian and his team have got close. The tin approach has resulted in some promising flame-bright superconducting oranges.
But shrinking the band gaps of such materials just that little bit further, to the point where a brilliant red is reflected instead,