I can thoroughly recommend all three of Frederic's plug ins (White Balance, Colour Matching and Exposure Correction). I've used them extensively, most recently on a difficult and lengthy family project involving film taken over many years on different and sometimes indifferent equipment and in different formats. I found all three of these plug-ins improved the results and were quick and easy to use, making my life much easier and saving a great deal of time.
Colour Match works well when trying to match the colours from two cameras or when trying to match the colours of the same scene when taken at differentr times. It's easy and quick - there's a demo on Frederic's web site at:-