I built the computer I'm using for photo processing a few years ago, to replace a very old and very slow PC I'd been using. For a while, I used Linux Ubuntu on this computer, which worked fine, but I wanted to use the Nik Collection so I reluctantly installed Windows 7. Nik ran fine with it, much faster than on my old Windows 7 laptop. However, I soon grew tired of the increasingly frequent Windows crashes, and the constant "critical updates". I said goodbye to Nik, and reinstalled Ubuntu. Yesterday, however, I learned how to install the latest WINE Windows program loader, used it to install Nik Collection, and I now have the best of both worlds: the stability of Linux and the utility of Nik. I'm one happy camper. Here are a few variations of a waterfall scene I visited a couple of weeks ago, generated using HDR Efex Pro 2. The rust color in the rocks and water is real . . . some of the larger rocks have significant iron deposits. The 4th image is from Silver Efex Pro 2.