Calceolaria flowers, bright bursts of yellow hitting retinas and CMOS sensors.

Bright reds and yellows mixed with dull greens.

Why do some colours have a powerful visual impact?

It turns out that specialised, light-sensitive cone cells packed onto retinas, are responsible. Three cone cell types, triggered by short, medium or long wavelengths send a cascade of electronic signals through the optic nerve to the central processor and decoded to produce vision.

What about the camera?

The camera’s CMOS semiconductor acts as a retina, imitating the architecture of the human eye.

Photosensitive light sensors arranged in a dense array on the chip are equiped with a light filter. Three filter types selectively allow light of short medium or long wavelengths to pass through and trigger the photosensor.

A cascade of electronic signals travel through integrated circuits to the camera’s central processor where they are decoded to form the beautiful images of Calceolaria flowers.

Short, medium and long wavelengths correspond loosely with blue, green and red colours in the spectrum.

That still doesn’t explain the stunning brightness of yellow.

The visible spectrum is the region of electromagnetic spectrum visible to the human eye. Light is characterised by its wavelength.

• Cone cells, seven million on each retina, respond to a range of wavelengths between 380 and 750 nanometers. A nanometer is one billionth of a meter.

• The range of wavelengths stimulating each cone type overlap to some extent.

• The peaks in the graph correspond to wavelengths triggering the greatest signal output through the optic nerve.

• Yellow wavelengths stimulate M and L cones close to their maximum output with maximum effect.

• Green wavelengths stimulate S, M and L cones towards their minimum output. They look dull by comparison.