if photons don’t have color, why does light have different color


if photons don’t have color, why does light have different color

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Photons have a wavelength, or a frequency, depending on how you want to look at it.

In your eyes are “rods and cones” which are sensitive to photons of certain wavelength ranges. Those are what we call colours. You have red, green, and blue cones (unless you have colour blindness or such) which react to those colours and you see things with them.

All things considered, it’s a fairly specific range of wavelengths/frequencies we can see.

Light is made up of photons. If your definition of colour says that light has colour, then photons have colour too.

There’s some argument about whether colour is a property of light or only the human sensory perception of light. If photons don’t have colour then light doesn’t either.

Light is generally made up of photons of many different wavelengths meaning that it can have colours (like magenta) that a single photon can’t. Single photons, or light made up only of photons of the same wavelength, can only have fully saturated spectral colours, like the ones you see with a prism or in a rainbow.

There is no property of light that actually contains color. Colors are constructed entirely by our brains as a way to process different wavelengths of light that our eyes are able to sense. Consider “forbidden colors.” These are colors when, compared to how your eyes perceive different wavelengths of light, shouldn’t exist. Our brains create them to try to make sense of the way our eyes are sensing different wavelengths of light that have a gap in it. [Magenta is an example of a color that shouldn’t exist.](https://www.reeditionmagazine.com/to-the-minute/magenta-the-color-that-doesnt-exist-and-why#:~:text=First%20and%20foremost%2C%20it%20is,corresponds%20to%20that%20specific%20color.)

Photons can be associated to specific colors, but not all colors can be associated to a specific photon.


Think of it like notes on a guitar.

If I pluck an open string and it starts vibrating at ~330Hz then listeners might recognize *”Oh, that’s a pure E note!”*.

Alternatively, if I put my fingers on a certain combination of frets and strum them together, the listeners might say *”Oh, that’s an E-major chord!”*.

Then, if some newbie comes up to me and says *”What string do I pluck to play that E-major chord you just played!?”* I’d have to explain that a “chord” isn’t played on a single string the way a “note” is, and that it actually requires multiple notes be played at once to produce the right sound.


Photons and light are the same way.

Any individual photon basically acts like a specific pure “note” based on it’s frequency and many of these notes get associated with specific “colors”. But! There are other “colors” that are more like “chords” and cannot be recreated by a single pure photon because they actually need multiple notes to be played together to produce the right feel.