Do we all see the same colours?

Actually, I'd say we don't. Colour is actually just an experience in the mind. Let's say for example, you're looking at a "green" object. Light from some source shines onto the object, and it absorbs every other wavelength besides the greenish wavelengths and a couple of blueish and yellowish wave lengths. The waves that haven't been absorbed are reflected off the object and into our eyes.

Once the light hits our eyes, then the three different cones in our retina (focused on long, medium and short wavelengths) will differentiate the wavelengths that have hit them and changes light energy into electrical energy, which is then (to make a longer story short) transmitted to the brain as a particular colour.

Now here's where people DON'T see the same colour. Some people have a defective cone type... or two... or three... and therefore their ability to differentiate colour is less than the normal person's. They'll still be able to see some colours, but the ones they can't differentiate will be grey (I think).

Ask me anything