Why are these lights all different colours and how can I correct them?

Question

I occasionally take panoramic city photos and I've noticed that certain sections of the cities have a lot of different coloured lights.

What causes these different lights? Some of these appear to be 'coloured' lights (the green and red for example) but there's a lot of purple and orange and white lights which 'look' white when you view them with the naked eye.

I've previously had issues like this and I've found that correcting using white balancing works wonders, however, I believe all these lights are of different temperatures so I cannot balance them all.

Is there any way to fix this?

Below is a snip of a picture from one of the shots:

Answer 1

The different colors are caused by different chemicals in the lights. The bright orange ones are sodium vapor. Actually, there are two types of sodium vapor lights, with different colors. The blue/purple are mercury-vapor lights. The green lights may be ordinary florescent lights. The light yellow are probably tungsten, perhaps from car headlights.

You are asking a philosophical question: which is correct? You have to pick one, so that you can correct the color temperature in post-processing. There is no answer. Its trivial to correct one of the types, but I know of no way to correct a collection such as this.

You could try to desaturate the photo, or even push it all the way to black and white.

Answer 2

i think it's better that you correct it zone by zone.because there are different color and kelvins it isn't possible to correct them at once.
but i think it isn't bad to have different color in one panoramic shot of city and it's attractive but you should try to improvement your work.

Answer 3

What Pat said, basically. I might add that your eyes and brains are fiendishly good at autocorrecting for this kind of light-colour variation, which means that you basically don't notice that it is there in real life. The camera on the other hand records the light at is is, not as it "ought to be".

Answer 4

Basically, your question comes down to understanding light and the way the human eye and the human brain do colour corrections automatically, versus the way the electronic parts of your camera record it, as Pat and Staale both pointed out.

The technical part of colour temperature versus camera sensors versus the sensor quality versus lens quality and all the other variables that ultimately give the end result is a completely different story.

To take your question into a different realm:

What would happen if you would try to give 4 individuals from - let´s say - Ghana, Texas, Finland and Marocco, shot in exactly the same natural light, the same skin colour?

http://www.ted.com/talks/beau_lotto_optical_illusions_show_how_we_see.html gives some really nice insight in the matter...