Light Pollution & the antidote....?

The following pictures are a single frame taken on a bad night. Forget about the bad tracking etc. that's not the point here. The point is light pollution and how to deal with it.
Canon 350D, 300mm lens, ISO200 and 180sec exposure.

Before Processing: (now you see what I'm up against)


After processing:


Processed only in Photoshop using Carboni's Astronomy Tools filters.

The trouble with trying to process out light pollution is that you tend (well I tend anyway!) to end up with overly blue stars when you get the background to black. Is there a way to get more realistic colour?

You can rebalance the colour afterwards - it stands to reason that if you take out orange - ie Sodium - which is red and yellow, then most of what's left is blue.

I've tended in the past to keep my exposures down to 30 seconds and my ISO at 200 but there is only so long you can do this. Which is why I am bringing this up now. You can see in the shot above which is only 3 minutes at a low ISO the kind of problem I am up against, the same shot at ISO800 would be incredibly yellow, and this is my darkest aspect it would be even worse for me shooting North over the city. Given that I now have a mount capable of longer exposures this is going to become more and more of and issue for me. So other peoples proven tips and tricks are appreciated and please no speculation - just the facts. Which is why I've started with the shot above.

John, there's a short article on my website.....

www.pevans.me.uk/html/articles.html

covering much the same ground. This is the artificial darkframe method, probably similar to what Noel Carboni's actions are doing.

This method is good for star fields but less good for nebula type objects as a lot of the nebulosity gets lost with the LP.

You can rebalance the colour afterwards - it stands to reason that if you take out orange - ie Sodium - which is red and yellow, then most of what's left is blue.

Well, yea obviously. But how exactly should you rebalance the colour? Just altering the balance of the image seems to either yellow the background or causes all stars to be white. To get the orion nebula correct you seem to almost need to paint the red back in or process the nebulosity separately. All of which leave you with a very fake looking image I've found.