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SeanKP
25-02-07, 12:24
I've been experimenting with some long-exposure night shooting recently with some mixed results. One thing that I can't figure out is why I often get a brown cast, particularly to the sky. Sometimes it looks quite neat but I'd like to also be able to achieve the nice crisp colours as displayed in Yelvertoft's photos of the cloth hall in Ypres (http://www.worldphotographyforum.com/gallery/showphoto.php?photo=14761&cat=503&limit=recent). Can anyone explain what is happening?

Thanks.

Sean

yelvertoft
25-02-07, 13:00
If you post an example of the effect you are describing, it would help in analysing what's going on. On first reading, light pollution from sodium lamp street lighting springs to mind but an example would help.

Thanks for the compliment on my shot. Apart from a bit of perspective correction, and subsequent crop, I didn't do anything with this shot, it's "as taken".

Duncan

SeanKP
25-02-07, 13:26
If you post an example of the effect you are describing, it would help in analysing what's going on. On first reading, light pollution from sodium lamp street lighting springs to mind but an example would help.

Thanks Duncan. My shot of St Pauls (http://www.worldphotographyforum.com/gallery/showphoto.php?photo=14406&cat=500&ppuser=897) is an example.

Sean

Canis Vulpes
25-02-07, 13:57
Thanks Duncan. My shot of St Pauls (http://www.worldphotographyforum.com/gallery/showphoto.php?photo=14406&cat=500&ppuser=897) is an example.

Sean

This is light pollution and is brown or really orange from low pressure sodium street lights. Duncans photo may have been more rural or lighting of the church may have overridden this pollution. I took almost the same St. Pauls photo and posted in the critique forum back in Feb 2006 with the same orange sky.

Leif
25-02-07, 14:18
I agree with Stephen. You are recording the light from the city scattered from clouds and dust in the sky. The solution is to wait for a clear sky, then it will be black, at least in shortish exposures. Also, if you want a bit of colour, you can wait for a nice sunset. If you take a look at the postcards sold in central London newsagents you will see some good examples of this. Of course it is easiest if you live in London, as you can never be sure quite how the conditions will turn out. I suppose these days we should all be taking pictures close to home to avoid needlessly burning fuel.

yelvertoft
25-02-07, 16:31
Duncan's photo may have been more rural or lighting of the church may have overridden this pollution.

The lighting in Ieper is far lower intensity than London, it's a small provincial town in rural Flanders. What you have in the St. Paul's picture is light pollution from the vast urban spread that is London. Even on a clear night, you are going to get the orange sky effect.

Sorry, there is no cure except to take pictures in less urban environments.

Duncan

Leif
25-02-07, 18:12
Even on a clear night, you are going to get the orange sky effect.


Some years ago I took some pictures of the Houses of Parliament and Big Ben at night with a clear sky and the sky came out black. I've attached two examples. They are not particularly good pictures, but they are quite good illustrations of technque. The first was taken long after sunset, and the sky is black. Any colour in the sky is electronic noise from the scan and is not present in the slide. (Yes this was pre-digital.) The second was taken just after sunset, and the sky has some colour. If you are really lucky you can get a lovely red sunset as the background. Sadly those are quite rare.

miketoll
25-02-07, 19:13
The air will be cleaner on a fine night after rain but light pollution will still be there. Its often recommended to shoot while there is still a bit of light in the sky as per yelvertofts second shot i.e. at dusk rather than when it is truly dark. I think a that makes for a more interesting shot but it makes the photography more weather dependant.

yelvertoft
25-02-07, 19:25
It was Leif who took the two pictures above, not I. And very good they are too.

I wonder how much difference there is with digital vs. film in picking up the orange tint? I've shot many cityscapes on film at night. I've just gone and had a look at one hanging on my wall, it has negligible orange glow.

miketoll
25-02-07, 19:30
Sorry to have given the credit to the wrong person Leif. Yes they are very good shots. Interesting question, you would have to set up a film and digital camera up side by side so the conditions were identical. Different films would make a difference too so its a bit complicated!

yelvertoft
25-02-07, 19:54
I should perhaps clarify by saying that I've taken traffic light trail pictures on digital cameras, out in the sticks, on different days, and under different conditions admittedly, and suffered terribly with light pollution from small towns several miles over the horizon.

Leif
25-02-07, 22:01
I think it all depends on the length of the exposure. A few seconds should be okay.

paul0510
26-02-07, 10:34
Sean,
quite honestly, I prefer the shot as is!

SeanKP
26-02-07, 23:23
Thanks everyone. What you are saying fits in with what I've been experiencing. The cloudier the weather the browner the sky certainly. And taking the shot at dusk seems to result in a bluer sky as Leif's great shots prove and I have found with my own shots of Parliament.

Paul, I tend to agree with you that the effect can be quite pleasing but it is always nice to have an understanding of these things so as to be able to predict how a shot might turn out and possibly turn that knowledge to your advantage.

Finally, since posting the message I have revisited some of the shots I have taken recently and played with the white balance in ACR with some variable but occasionally pleasing results. I have gotten into the habit of always shooting in RAW anyway due to my underwater photography but I think it probably can be useful in a night shooting scenario too.

blackmarlin
07-03-07, 22:12
Sean if you look at my picture "Light trails" you will notice that the sky is brown, this is caused by the lights of Manchester and Warrington, as this picture was taken in the Cheshire countryside I think it shows just how bad light pollution is beginning to get. Overall the shot of St Pauls is good but the sky spoils it somewhat.

Alan

carman
09-03-07, 21:11
Sean if you look at my picture "Light trails" you will notice that the sky is brown, this is caused by the lights of Manchester and Warrington, as this picture was taken in the Cheshire countryside I think it shows just how bad light pollution is beginning to get. Overall the shot of St Pauls is good but the sky spoils it somewhat.

Alan

Light Pollution I'm afraid.:(