A few months ago, I had the opportunity to shoot the Stone Mill with my friends Bob Lussier and Steven Perlmutter. They conduct workshops in the Lawrence mills and I highly recommend them. This particular workshop was focused on light painting. I haven't done much light painting photography, so it was an interesting and learning process.
One of the things that makes the Stone Mill a great subject for night photography are the lights that come on through the windows that create great shadows on the walls. These shadows, coupled with the use of colored lights, make some really cool effects. I typically might try some HDR processing with the high dynamic range of light, but the Lightroom has come such a long way in the past few years that it wasn't necessary. I also used Lightroom's new feature in the Transform Panel (Guided) which worked amazingly well. It was quite simple to use and it did wonders straightening the windows.