Fine-tuning colour

The course materials go on to give information about how within Photoshop Elements there are a number of ways to alter the colour of digital photographs ie Enhance>Adjust Colour and Adjust Brightness/Contrast these menus are not available in Photoshop CS4 which I noted in Project 4...still presuming that the alternative route with CS4 is via Levels or Curves Layer.....examining the image Goathland I couldn't find any neutral's at all which didn't really surprise me as I couldn't find any in my Commercial Road image. Using the Auto Colour adjustment the image altered very, very slightly and seemed to lose a little blue cast which wasn't that noticable until the adjustment was done. I had to zoom into the roof quite closely to see the change. On one hand it is quite surprising that not many of the hues in an image are truly neutral but on the other when you consider white light is not really white and secondary colours are made by the mixing of primary colours it is to be expected...