Photoshop Tutorial - Advanced beginners and Intermediate Users

In my last tutorial: Quick and easy "Color Cast" correction
http://microstockpix.com/tuts/colorcast/colorcast.html

There was some hemming and hording about the fact I did not include a way
to find and set the neutral gray point on a colorcast image.

Well although the tutorial was intended for beginners, all those more advanced
users jumped all over me for not including it. So here it is. I hope those advanced
Photoshoptic Surgeons stay off my case now!

http://microstockpix.com/tuts/gray/gray.html