Photoshop tutorial in foggy conditions, from Purisima Creek Redwoods
This photograph was taken in Purisima Creek Redwoods, specifically on the Harkins Ridge Trail. This is one of the most beautiful locations in the Bay Area. There are stunning vistas and monstrous Redwoods. It is a must-hike for anyone in the area. But there are also quieter, more intimate scenes of equal beauty, if one keeps their eyes open. This picture is such a scene. As I rounded the bend, I was struck by the simple, peaceful beauty of the dirt trail, flanked by wildflowers, passing between two evergreens, while the sunset-colored fog coated the scene in varying degrees of mist.
But it can be hard to get photographs in scenes like this to match the splendor of what you witnessed. In particular, the white blanket of fog can mess with relative brightness of each portion of the scene. To pull any detail out of the fog requires a short exposure, making the foreground very dark. It can be difficult to blend multiple exposures together, because the fog has a way of blurring the edges of things like trees and bushes. However, if you know a few tricks, it becomes easier. Hopefully some tricks shown here can help you blend foggy images more successfully.
First, import the images in Adobe Camera Raw
As always, the first step is to import your images in Adobe Camera Raw (ACR). The image shown is actually an eight exposure composite. It sounds like a lot of work, but composites are often needed to achieve the vision in my head. This image consists of four "frames," with two exposures each. When I say frame, I mean the camera pointing in a specific direction, looking at a specific composition. The reason I split this image into four frames was to keep the perspective distortion down. I had a wide angle lens and could have captured the same items in a single frame... however, to do so, I would have had to zoom out to a very wide angle. This would inevitably shrink the background objects, such as the trees, and draw most of the attention to closer objects, such as the road. I wanted the two trees to be as prominent in the composition as the road, so I zoomed in a bit, and then used as many frames as were needed to include all of the objects I wanted in my photograph: the road, the wildflowers, the two trees, and some empty fog to the left. Each frame needed two exposures: one for the foreground objects, and one for the brighter fog.
Screenshots below show my ACR settings for each exposure for each frame. Notice that the white balance is not the same for the two exposures within each frame (I found different white balances worked best for the fog versus the foreground), but they are the same for similar exposures across different frames (because if the white balance differs, stitching the four frames together will be very difficult).
Notice the settings for the darker exposures. First of all, they required more of a saturation bump to bring out the colors of the fog. It's important to keep balanced interest in your composition, and the color in the fog was necessary for that. Also important was the -20 setting for the clarity, and the +10 setting for fill light. The purpose of these were to make the edges of the two evergreen trees hazier and brighter, which will be useful when blending the two exposures together.
Blend the two exposures together for each frame
The next step is to blend the two exposures together for each of the four frames. I recommend at this stage to only try to get the blending done perfectly, but not do any other sort of tweaking. The reason for this is that you will likely also want to do the same sort of tweaking on each of the other frames, and will find it difficult to do it identically the same. It's best to wait until the frames have all been stitched together before doing more adjustments.
The blending step here was actually quite easy, because of my adjustments to the raw images. Since the outer edges of the trees are bright enough in the dark exposures, it doesn't matter if they show through a little bit. This makes blending a breeze. First, I pasted the brighter exposure over the darker one. Then, I selected the fog with a magic wand (make sure it's set to 'non-contiguous'). I then expand the selection by 40 pixels, then feather it by 100. I then simply do a "Layer -> Layer Mask -> Hide Selection," and voila! I show this below in screenshots, for 2 of the 4 frames. It's important to note that in images where the blending borders have vastly different brightnesses within the two exposures, this method will not produce good results. It will also produce bad results if the two exposures have slightly misaligned edges, for instance if you had taken them by hand, or if it had been really windy and the trees had been swaying. Nevertheless, it's a good method to try first, and it worked great here.
Stitch the Frames Together
The next step, now that each of the four frames has been blended, was to combine the four frames together. For this, I used File -> Automate -> Photomerge. The method which ended up working best was the cylindrical method, as shown below. I typically try "reposition only" first, as it yields the most un-distorted image, if it succeeds. However, it didn't succeed for this image, as there was significant amounts of perspective change between the four frames. If reposition only does not work, I find that cylindrical of spherical is usually best. After the frames were stitched, all I had to do was rotate it, crop it, and then use the clone stamp to fill the empty corners.
To my eye, the stitched result has the trees tapering up a bit too much, as if the trees are leaning away from the viewer. That's simply an unavoidable consequence of the perspective from where I took the photo, given that I was close to these tall trees. To correct this, and make it feel less like the trees are leaning away from the viewer, I used the "Edit -> Transform -> Distort" feature. This allowed me to widen the top, which can pull the treetops "back towards" the viewer.
Final Adjustments: Saturation and Match Color
I still felt that I needed to draw the beautiful colors out a tad more, to match my memory of my hike. However, different portions of the photograph needed different amounts of additional saturation. The fog needed quite a lot, the flowers just a tad, and the path none at all. So I selected these regions separately, and applied differing levels of saturation. Because these adjustments are only for the web version, I simply made the changes directly, instead of in an adjustment layer. If you are making these changes to the master file which will be used in printing, be sure to make the changes in an adjustment layer instead! After the changes to saturation, one last change was to use the "Image -> Adjustments -> Match Color" feature to give some color contrast between the warm and cool parts of the image. After that, the only additional thing I did was sharpen for web, which included the approach I detail on some of my other hubs, including the "St Mary Falls" walkthrough. That's it! Hope you've enjoyed this visit into Purisima Creek Redwoods, and glimpse into my methods.