TUTORIAL: How to Create Car light Trails Images Using Lightroom and Photoshop?
Have you ever seen photos with nice car trails and wonder how to make them? Or have you tried taking car light trails in a road that not many cars pass by and you end up with one or too streaks that don’t look that good? In this tutorial I’ll give a step by step guide of how to make better car trails photos using Adobe Lightroom and Photoshop. At the end of the page there’s a 3:30 minutes video in which I did the steps described here with an image I recently took. If you don’t feel like reading go ahead and skip to the end. What are car trails? Car trails are the streaks of light that you see in images, these are created through long exposures. Typically you can make photos in which the cars are just a line of light through your image by making exposures that are longer than 1/10th - 1/3rd of a second depending on the speed of the cars passing by (and of course that they have their headlights on!).
There can be several difficulties to do this:
1. Is not dark enough and long enough exposures are difficult to obtain without ND filters.
2. High dynamic range scene and if you expose for too long part of the image gets blown out (sunset, sunrise situations).
3. You are able to get long exposures but there’s camera shake that you can not control (wind, vibrations on a bridge, etc) so you need to make shorter exposures to mitigate this.
4. The longer your exposure the longer the car trail but as your exposures get longer the light becomes fainter.
On highways usually an exposure time of around 1-3 seconds will give you long enough car light trails that look nice but there might not be enough cars passing by to make them look great overall. The goal of this tutorial is to take multiple exposures and the blend them in Photoshop to create rich and dense car lights on your image.
Step by Step process
Select your base exposure and make you global adjustments in Lightroom. In this case I selected the images that had the better sky of all the exposures I was planning on blending and made global adjustments of exposure, white balance, highlights, shadows, whites, blacks, etc.
Select all your photos and synchronize them in Lightroom. This will apply the same adjustments you made to your base exposure to all your selected images. Make sure that you have selected your base photo before clicking on synchronize. You’ll notice that some of you images might look brighter and some might look darker. This is expected as probably the base exposure of each image is different but when you synchronize them all get the same boost in exposure, shadows, highlights, etc as your base exposure. This difference in exposure will be corrected in the next step.
This is, in my opinion, the most important step to make sure you get a smooth blend in Photoshop. Select all you images and go to Setting> Match Total Exposure. As with the previous step, make sure that you have your base exposure selected, as Lightroom will apply the exposure of this one to the rest of your images. Here Lightroom will make all your images the same overall exposure. Now you will see that all the images look more or less the same.
With all the tone-balanced images selected, right click and go to Edit in> Open as Layers in Photoshop. This will bring all your photos into a single Photoshop file. This could take some time depending on how many photos you’re using and how fast your computer is. This is a good time to make some coffee, take a nap, go for a walk, etc.
Once your photos are imported into Photoshop, look for your base photo and drag it to the bottom of the layers list (is a good practice to also rename it). Next select all the layers and go to Edit> Auto-align Layers and click ok in the prompt window. This will make sure that you are correcting for small changes in the camera position that might have occurred while taking the photos. Again, this might take some time depending on your computer and quantity of layers. Time for a second cup of coffee (?)
Select all the layers but the base layer and change the blending mode to lighten. The lighten blend mode analyzes the layers and reveals the brightest pixels of each layer. This is why Step 3 is so important. By all the images having the same exposure only (mostly really) only the car trails will change from image to image. In my image the sky changed from image to image to it looked weird and had to mask it out in the next step.
Create a black layer mask for each of the non-base layers. Hold Option (Alt on PC) while you click on the Add Layer Mask button and a new black mask will be created. Once you create all the black masks, pick one of your images and paint with a white brush to reveal the areas where the car light trails are. Once you finish one mask, hold the command key (control on PC) and click on the layer mask on the Photoshop layers list, this will make a selection of the mask. Now with the selection loaded (you’ll se the marching ants) go to each of the other black masks and click Command (control on PC)+I on each of them. This will invert the mask to white but only on the selection. Finally, I like to put all my “car trails” layers into a group folder for organization purposes. You can do this my selecting the corresponding layers and click Command (control on PC)+G or by dragging the layers to the folder icon at the bottom of the layers index panel.
Step 8 (Optional)
You your car-trails blend is done you can now make final adjustments to the image. For this example I added curve layers to bring the sky even more and lighten the foreground a little bit.
This 8-step process is relatively easy and doesn’t require advanced photoshop skills to do it. Bellow is a short 3:30 minutes video with the step-by-step process described above. If you have any question leave a comment below and I’ll try to answer as fast as possible.