Light trails Play with traffic

Transform passing vehicles into glorious streaks of colour, with James Paterson

WE PHOTOGRAPHERS have a bit of a love/hate relationship

with movement. At times it’s a real pain and we strive to keep it to a minimum; at other times, we want to celebrate it in all its blurry glory.

The motion of traffic at night definitely falls into the latter category. If you set a long exposure in the low evening light, the smooth motion of the car lights creates wonderfully evocative streaks of colour through the frame.

This is one of those photo projects that reveals the magic of photography – and the best part is, it’s easy! Anyone with a DSLR and tripod can do it. It’s a great way to get started with long-exposure photography, as there’s no need for extra filters or even a cable release.

If you find you usually stick to the auto exposure modes, a project like this offers a gentle introduction to the Manual exposure mode. To get the long shutter speeds you need, you have to restrict the amount of light that can get in by adjusting other exposure settings. Use a high f-number such as f/16 to decrease the size of the opening in the lens and restrict the flow of light. Set a low sensitivity, such as ISO 100, so the sensor requires more light. The challenge is finding an interesting composition for your shot. Winding roads and mountainous scenery work perfectly, but why not try a multi-lane motorway, a city street, or a knotty junction? Another challenge is timing – you want to capture a decent array of lights but at night, especially, traffic can be rather sparse. However, you can always shoot several frames then combine them with simple Photoshop skills, as we’ll explain.

Once you’ve mastered this technique, why stop at road vehicles? Trains, boats, bicycles and any other moving object that has lights will produce similarly amazing results.

Step 1

Fix your DSLR to a tripod. Look for an angle where the winding road begins close up then recedes into the distance, as this will make the most interesting lines. Try a low-down or high-up view, and frame loosely to account for different-height vehicles.

Step 2

Rather than shooting in pitch-dark, try just after sunset so there’s still detail in the sky. Even so, autofocus can struggle to lock on in low light, so focus on a point a third of the way into the scene, then switch to manual focus to lock it.

Step 3

Switch your DSLR to Manual exposure mode. All scenes are different, but here’s a good starting point for exposure: set the aperture to f/16, shutter speed 30 sec and ISO 100. If the image is too bright or dark, try adjusting the aperture until you’re happy.

Step 4

Shoot plenty of frames as vehicles zoom by. Differences in height make the trails more varied (as will flashing lights, which appear as dashes). Take care not to nudge the camera between shots, as you need all the frames to be in alignment to blend them together.

Step 5

Open all the images you want to blend in Photoshop. Choose one frame as the base image, then go to another image, Select All (Cmd/Ctrl+A), Copy (Cmd/Ctrl+C), then go back to the base image and Paste (Cmd/Ctrl+V). Repeat for all the other images.

Step 6

In the Layers panel (Window > Layers), change the Blending mode of all layers to Lighten, which effectively lets you overlay the trails on top of one another. If any other areas look messy, use a Layer Mask or the Eraser to remove them from the mix.