Colour cast correction

I came across this which some may find useful.

One of the easiest ways to correct a colour cast in say a night-shot is to use the Average Filter in Photoshop. There is a YouTube video tutorial about half way down this page, which will give you a good starting point to work from

http://www.the-graphics-tablet.com/color-correction.html

I would be tempted to use the Eye Dropper tool on something that I know to be white and while looking at the RGB values on the Info palate, adjust the opacity until the values are more or less the same.

For this and the Threshold Adjustment Layer mentioned later, I would use the eyedropper sample size of 5x5 Average rather than a single pixel sample.