Tag Archives: Colours


This is rambling article about human vision.

Blind spot
It all started when we were having fun with the “blind spot”. Its been known for ever that the blind spot exists. It is now well-known that is the position in the eye which has no receptor cells from where the optic nerve leaves for the brain.

I couldnt get it to work for it – but the wikipedia page worked perfectly for me. It was awesome !!!



Colours have always been fasicnating. Aesthetically, scientifically. We know that there are basic colours – red, blue and green – from which all other colours can be derived. Changing the intensities of these colours and mixing them can produce virtually every other colour. And can be very entertaining too. It doesnt have to be exactly these three colours, but can be any three colours from three appropriate group. Why 3 ? It turns out, and it seems so obvious in retrospect, that there are three kinds of cone cells in the eyes. These cone cells are responsible for colour perception and their photoreceptors are of three kinds – most sensitive to red, geen and blue !

It turns out then – that night vision – vision in dim light – which is colourless – is due to biology again. Rod cells are responsible for this vision, as opposed to cone cells. And unlike cone cells they dont have the photopigment in them.

Some notable scientific greats have been intrigued with colour and have focussed their energies there.
Schrodinger, the genius who did many things, but is mostly known as one of the founding fathers of the quantum theory, and his quantum mechanical wave equation. He published a number of papers in the field of color, color perception and colorimetry.
While on the topic, it was Schrodinger’s book “What is Life?” that led to an entire generation turning their energies to research in that line that eventually led to the discovery of genes and established the field of genetics. Continue reading