curves

I have been using PS for years but for my own art purposes not in a professional environment where critical color and tonal correction is needed. I have some basic knowledge of curves but would like to know more, any free tutorials out there that you know of? I know there are some good videos on the subject but cant afford them at the moment.

Thanks

Richard

any free tutorials out there that you know of?

google is your friend! < http://www.google.com/search?q=photoshop+tutorial+curves& ;ie=UTF-8&hl=xx-elmer&btnG=Google+Seawch&lr=lang _en>