Question: why do we see colours

Rowena Fletcher-Wood answered on 20 Mar 2014:

We have cones in our eyes for green, blue and red which identify colours in the world. Where they are and how many determined what colours we can see, so we almost certainly see colours slightly differently from each other! Certainly people do with colour blindness. Red/gree colour blindness is the most common and occurs mostly in men. It is inherited so if there is colour blindness in your family you are more likely to get it.

Colours are formed by the interaction of light with objects. Those objects absorb some light and reflect some. Our eyes pick up the light that is reflected and those wavelengths give us the colour. Wavelengths outside teh visual spectrum still interact with matter and are reflected or absorbed (like infra red!) but we can’t see them because our eyes don’t know how to pick them up.