Working on some light painting images. This photo was taken in the Dupont Underground in Washington DC. It's an area beneath Dupont Circle that served as a trolley station until 1962. In the mid-90's portions were refurbished into a food court, but that didn’t last long and it now sits in disrepair. I used a headlamp to illuminate this tangle of wires on the cement floor. If you want the greatest control over your light painting try combining multiple images. For each photo you can illuminate a different part of your composition, then put the images together to take the best of each one. This approach affords you greater precision because you can focus on getting the lighting just the way you want for one area. You don't have to try to illuminate the entire composition in a single exposure.
For this image I combined the following five exposures:
The top two thumbnails are the base images, providing the overall illumination for the ground and the wall. I then used the remaining three photos to bring in the strong directional lighting from the bottom left corner. The images were combined using layer masks in Photoshop. To finish things off I used Color Efex Pro 4, and applied selective darkening to direct the viewer's eye and shape the visual flow of the image.