I am looking for some advice on how to improve the colour of the sky during night time photography. At the minute I take most of my photographs in central london and the sky colour can vary by a large degree some deep black, some a blue colour and others sometimes appear a slightly polluted colour. Ideally I would like to take photos that show the sky with a deep dark colour.
I am wondering if it has something to do with camera settings or whether I should be looking at the night time conditions whilst taking the photographs. I also use Photoshop to edit the photographs so if anyone has any tips on how to improve the sky conditions this way that would be great.