Hi Mat, and welcome to the list. I liked your Antarctic work, BTW. As far as Photoshop goes, go ahead and play with the sliders all you want. Just don't save anything without backups! There are a number of good books on Photoshop techniques, but since finding a good bookstore on the southern most continent might be a little difficult, if you have iTunes (available or Mac and Windows), there are a number of podcast tutorials you can download and watch. Depends on your bandwidth and 'net time of course.