AA Edit | Shall We See New Colours Soon?

Before people watched the American movie The Power of Love in 1992, they might not have believed that one could introduce depth into a film. But now, 3D films are as common as any other form of entertainment. Unless researchers challenge the norm, they will not earn a place in history. A similar piece of research, undertaken on the retina, claimed to have produced a new colour, olo, which cannot be seen by the naked eye.

Human eyes can perceive only a narrow band of light rays — between wavelengths of 400 nanometres and 700 nanometres — in the colour spectrum. There is a vast range of light rays, including gamma rays, X-rays, and microwaves, which we cannot perceive.

The eye’s physiology, as the new research showed, plays a significant role in the perception of colours. The retina, which receives the input of light rays and sends it to the brain for colour interpretation, is composed of three types of cone cells: S (short wavelength or blue), M (medium wavelength), and L (long wavelength or red). While the S and L cones activate independently, perceiving blue and red respectively, the M cones do not become stimulated on their own and require the help of neighbouring S or L cones to perceive green.

As the M cones do not activate independently, no human in history has ever been known to have seen the colours that this part of the retina could produce. The researchers used a laser to stimulate the M cones independently, which resulted in the perception of an entirely new colour. This new colour, which is closest to an intense teal, cannot be accurately reproduced without it.

Though this discovery does not have immediate practical value, it could potentially lead researchers in material sciences to produce new colours. If one could time travel into the future, the world might perhaps be more colourful than it is today.