# The Naked Scientists Forum

### Author Topic: how many colours are there?  (Read 4248 times)

#### jezza

• Jr. Member
• Posts: 36
##### how many colours are there?
« on: 14/09/2006 21:46:54 »
well, how many differnt colours are there, could it be infinate, surly theres a limit to how much you can mix it?

#### lightarrow

• Neilep Level Member
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##### Re: how many colours are there?
« Reply #1 on: 14/09/2006 22:05:21 »
There are infinite colours. I can't understand well what you mean with "surly theres a limit to how much you can mix it?" You mean "how many colours you can create by mixing two or more?" In this case the answer is: infinite as well.

For what concerns the ability to perceive different colours, that's another story; we surely are not able to perceive infinite different colours, but, however we can perceive a great number of it. I actually don't know how many, but of certainly it depends on the single individual.

#### another_someone

• Guest
##### Re: how many colours are there?
« Reply #2 on: 14/09/2006 23:28:23 »
quote:
Originally posted by lightarrow

There are infinite colours. I can't understand well what you mean with "surly theres a limit to how much you can mix it?" You mean "how many colours you can create by mixing two or more?" In this case the answer is: infinite as well.

For what concerns the ability to perceive different colours, that's another story; we surely are not able to perceive infinite different colours, but, however we can perceive a great number of it. I actually don't know how many, but of certainly it depends on the single individual.

What do you mean by 'colour'?

Is not colour simply a matter of perception, and if there are limits to what we can perceive, then do not those limits actually define the limits of colour?

If you are asking whether there is an infinite number of possible frequencies of electromagnetic waves, then even then, there may well be quantum limits on how close two different frequencies may be, and equally there must be an upper limit to the amount of energy a wave can contain, because there is a limit to the amount of energy in the universe.

George

#### lightarrow

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##### Re: how many colours are there?
« Reply #3 on: 15/09/2006 08:01:45 »
quote:
Originally posted by another_someone

What do you mean by 'colour'?

Is not colour simply a matter of perception, and if there are limits to what we can perceive, then do not those limits actually define the limits of colour?

If you are asking whether there is an infinite number of possible frequencies of electromagnetic waves, then even then, there may well be quantum limits on how close two different frequencies may be, and equally there must be an upper limit to the amount of energy a wave can contain, because there is a limit to the amount of energy in the universe.
Welcome back another_someone.

I really didn't know about quantum limits on how close two different freq. can be. Can you explain me?
About an upper limit for a wave's energy, it's true, but I was actually talking about a limited range of frequencies, that is, the visible range.

Your question "what is a colour" is very appropriate; I didn't go into this in order not to complicate much the answer.

#### Gaia

• Sr. Member
• Posts: 397
##### Re: how many colours are there?
« Reply #4 on: 15/09/2006 11:40:48 »
On a purely subjective level it also depends if you're colourblind, immediately negating the 'infinite' number of colours one can perceive, and on the species. There are also some people who have a limited number of cones in the eye and therefore cannot process the 'colour'.

Wikipedia gives a good general discussion of colour perception.
http://en.wikipedia.org/wiki/Colour_perception

Gaia  xxx

#### neilep

• Withdrawnmist
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##### Re: how many colours are there?
« Reply #5 on: 15/09/2006 15:49:15 »
If colours didn't exist then colour television would be very boring and paint manufacturers would have a very limited palette....and traffic lights and Christmas trees would be really quite banal.

Regarding Colour blindness...is it correct that it's mainly men who are affected ?...I suppose I should click on Gaias link that she has most generously provided...

OH..for our american chums... " colour " = "color "...I know it's hard for you !!..please try to keep up !!

Men are the same as women, just inside out !

#### neilep

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##### Re: how many colours are there?
« Reply #6 on: 15/09/2006 15:51:43 »
Yep..seems to be mostly a blokey problem http://en.wikipedia.org/wiki/Colour_blindness

Men are the same as women, just inside out !
« Last Edit: 15/09/2006 15:52:08 by neilep »

#### another_someone

• Guest
##### Re: how many colours are there?
« Reply #7 on: 15/09/2006 17:23:17 »
quote:
Originally posted by lightarrow
Welcome back another_someone.

Thank you – it is nice to have a stable connection again.

quote:

I really didn't know about quantum limits on how close two different freq. can be. Can you explain me?

I was thinking about limits such as the plank length, that may present a lower limit to which two different wavelengths may be discriminated.

quote:

About an upper limit for a wave's energy, it's true, but I was actually talking about a limited range of frequencies, that is, the visible range.

Visible to what?  Many birds and insects can see into the ultra-violet, while many mammals have far more restricted spectrum of vision than humans (some may not even have colour vision at all).

George

#### lightarrow

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##### Re: how many colours are there?
« Reply #8 on: 15/09/2006 17:30:14 »
quote:
Originally posted by another_someone

I was thinking about limits such as the plank length, that may present a lower limit to which two different wavelengths may be discriminated.
Ok. Thank you.

#### The Naked Scientists Forum

##### Re: how many colours are there?
« Reply #8 on: 15/09/2006 17:30:14 »