Night Sky Red Haze Question

[c5jr]

Hi,

I am pretty new to photography and have been doing some night shooting. In a few of my photos at night I have been noticing a red haze showing up in the pictures. Is this noise? Light from he city at long exposure? What can I do to minimize this in camera and post process? I have attached a photo as an example (I know not a good shot). This is my first time posting so hopefully the attachment works okay.

Nikon D3100
18-55 kit lens
ISO - 100
Aperature - F8
White Balance - Auto
Shutter - 10 seconds

 

[pgriz]

Back glow from city lights. If atmosphere is dusty or polluted, effect is stronger. Low clouds tend to reflect light, and in general there's a lot of light pollution. The way around is to shoot right after a rain, which tends to clean out particulates from the air, and if the sky is clear, then there will be less reflected light. Another technique is to use relatively short exposures (which will minimize the recording of the relatively dim skyglow), and if necessary, stack the photos.

 

[analog.universe]

It is light from the city... If you shoot in the city it's going to be there no matter what, but you can still improve your results a little. The red color cast that it has is because artificial city light tends to be pretty warm, and auto white balance isn't that good at correcting for it. You can set the balance in camera to tungsten, or even warmer by dialing in a specific temperature. (anywhere from 2000-3500k in these sorts of scenes, depending). This will balance out your color, but you'll still have bright skies. In post process you can use the curves tool to bring up the black point (just grab the node on the bottom left and move it to the right). Use care though, because all the dark parts of the image will be affected, windows, etc...

Ideally you should be shooting in RAW. This way white balance, and curves adjustments, and anything else can be custom controlled in post-process to yield the best results. Shooting jpg's means the camera decides a lot of stuff for you, and doesn't leave you much to work with when you want to do your own post processing.

 

[KmH]

Also known as 'air glow' or 'light pollution'.

Cities near major astronomical observatories often have lighting ordinances that keep most outdoor lighting from being able to shine upwards.

 

[c5jr]

Thank you for the responses!