• Question: If the colour we see is just a reflection, does that mean that everyting really has no colour?

    Asked by stevebuck to Adam, Catherine, Karen, Leila, Nazim on 14 Mar 2012.
    • Photo: Catherine Rix

      Catherine Rix answered on 12 Mar 2012:

      We see something as coloured because it absorbs some wavelengths of light, but reflects others. Colour is really how our eyes percieve the diffirent wavelengths of the reflected light, many animals don’t see in colour at all.

    • Photo: Adam Stevens

      Adam Stevens answered on 12 Mar 2012:

      That’s a very interesting question, and a lot of intelligent philosophers have thought very hard about it!

      What you’re asking is whether colour is an intrinsic property of an object.

      Like Catherine says, something looks green, for example, because it absorbs red and blue light and reflects green light. So to our eyes, it looks green.

      However, if you looked at the same object in blue light, it would look black! Or if you looked at something yellow in red light, it would look red! So the colour of something definitely depends on the light you look at it under, so it /can’t/ just be a property of the object!

    • Photo: Leila Battison

      Leila Battison answered on 12 Mar 2012:

      Ace question! Did you see the latest BBC Horizon, ‘Do you see what I see’? It is all about colour and really interesting. Also, I helped to film it!

      It all comes down to how you define colour really. Colour is what our brain interpret when our eyes recieve certain wavelengths of light. So without eyes, is there colour? Like the tree falling in the forest, that might or might not make a sound, does a wavelength of light make a colour if there aren’t eyes to see it.

      Scientifically the answers to both these questions is probably yes, but its hard to draw the line. It’s a fun philosophical question to think about though!

    • Photo: Karen Masters

      Karen Masters answered on 14 Mar 2012:

      Hmmm. Well some things radiate – not just reflect light, and so I suppose they really have a temperature. A great example of that is the Sun. It looks yellow to use because of it’s temperature which puts most of its radiation in the yellow part of the spectrum.

      Oddly the name for this type of object – with a colour which depends on its temperature, is a black body. So the Sun is the brigtest black body in our solar system. Most of the other objects we can see because they reflect sunlight only.

    • Photo: Nazim Bharmal

      Nazim Bharmal answered on 19 Mar 2012:

      It depends on how the light is created. You can either see the colour of an object when light is reflected from it, which depends on what colours are in that light. Or, the light can be created by the object itself and
      then we always see the same colour. Good examples are a coloured light shining on a white sheet: we always see the colour of the light and not that the sheet is white. But if we set the sheet on fire (!) then we see the oranges and yellows of the flames, and any lights being shone don’t change that. So there is such a thing as absolute colour.

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