• Question: how do you see the same colour as me

    Asked by Jessica on 19 May 2025.
    • Photo: Ruth Pegington

      Ruth Pegington answered on 19 May 2025:

      The colour you see is due to the light coming into your eyes and being detected the cells in your retina and then your brain interprets this signal.
      I’m not sure we can know for sure that we see exactly the same colour, but if there are differences in the cells in the retina we might see slightly different colours and call it the same name. People that are colour blind (different distribution of rods and cones- cells in the retina) do see colours differently.
      Hope that makes sense?
      I looked for a good explanation and thought this was a good one: hope it helps!
      https://www.amnh.org/explore/ology/brain/seeing-color

    • Photo: Ioanna Bezirtzoglou

      Ioanna Bezirtzoglou answered on 19 May 2025:

      Hi Jessica, that is a great question – we actually have no evidence that we are all seeing the exact same colour, or rather interpreting what we see as the exact same colour. But we, as a society. early on decide what colours ‘should’ look like, even if you might be able to see a slightly different colour variant than someone else when you are looking at the same ‘red’

    • Photo: Martin McCoustra

      Martin McCoustra answered on 20 May 2025:

      This is an interesting question and the two other answers highlight the problem in addressing it. First, the process by which we see is pretty much the same for all of us. Light falls on the retina at the back of the eye and there are light sensitive cells that respond to certain colours. These cells produce an electrical signal that is interpreted by your brain. That’s where the difficulty arises… we can’t say if we all interpret these signals in the same way.

    • Photo: Calum Cunningham

      Calum Cunningham answered on 28 May 2025:

      To add to the excellent answers so far, it’s true that we don’t have any way to verify our brains are interpretting colours the exact same, but physics can help us define a colour because colour depends on the wavelength of light.

      For example, a red laser pointer has a wavelength of about 650 nanometres (nm) whilst a green one has a shorter wavelength of 530 nm. So, we can know for sure that we’re both looking at a ‘green’ laser, even if the colour in your mind looks completely different to the colour in mine!

      P.S. try to imagine a brand new colour that doesn’t exist… (it’s impossible!)

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