Merging images – landscape photo tip from Summit presenter Jay Goodrich.

Utah skyscape, (c) Jay Goodrich

Utah skyscape, (c) Jay Goodrich

On a recent trip to the desert southwest of Utah I photographed an amazing sunrise as a winter storm front approached my location. For landscape photographs such as this one, I prefer to use a graduated neutral density filter in the field to balance out my scene’s High Dynamic Range, but the composition that I selected for this particular moment did not allow me to follow this practice for two reasons. One, my horizon line was very erratic and jagged, which would have made the filter’s delineating line visible along the top of lower peak. Second, I decided to use my new Vari-ND filter from Singh-Ray to slow my shutter speed drastically, which blurred the clouds in the sky to give them a more dramatic look as they drifted across my composition. This filter had my shutter speed so slow that my standard practice of hand holding the grad ND filter still in front of my lens, for the prescribed amount of time, would have been next to impossible.

So with the given parameters how would you accomplish the above image? Simple, take two exposures, one for the sky and one for the foreground then merge the two in Photoshop CS5 to yield the desired results.

As you can see I have selected the two exposures in Lightroom 3, which is what I use to manage my catalog of images and make global adjustments to all of my raw files. These two files have had those initial adjustments already done. From here I right click on my main selected image and choose Edit In>Open as Layers in Photoshop…Lightroom sends my files to Photoshop and stacks the files in layers in a single document. Once the files have loaded you may need to adjust the order of the layers. I always put my darkest image on top, lightest on the bottom, and any consecutive images from darkest to lightest in between the two by simply dragging and dropping them in the appropriate locations.

In this next screen shot you can see the two layers, the darker on top which I have temporarily turned off for my next step, which is to select the area of the sky on the foreground image that I want to replace. The reason I use the lighter image to select the sky is because it is easier to make a selection in an area that contains less contrast and detail. To make the selection, I am using the Quick Selection Tool which I have circled in the upper left of the image in red. You can also see the “marching ants” of my selection in the image.

Once you have the whole sky selected, turn your upper/darker image back on and click on it to make it the current layer. Take note of how I had to shift the upper image just a bit to get it to line up perfectly with my foreground image below. My tripod collar had a bit of play in it and I managed to spin the lens a little in between exposures.

Next, with my darker image layer selected, and my “marching ants” selection still current  from image 2 above, I pick the Add a Mask icon at the bottom of my layers palette. You can see that Photoshop creates a Layer Mask on my darker layer revealing the sky/marching ants selection and concealing the darker part of the foreground which was not selected. A sentence to always remember when using layer masks in Photoshop is “White reveals and black conceals.” Next look at the dividing line between both images, it is quite noticeable after this process. Adobe has made some major refinements to their Masks Palette in Photoshop CS5, so now we can easily adjust our mask line in seconds. Make sure your Layer Mask is selected in your darker layer as it is in my image above noted by the smaller red circle in the larger one.

With our final adjustment we need to open the Masks Palette and then select the Mask Edge…option. This opens a dialog which allows us to adjust the edges of our selected mask. As you can see in the Refine Mask dialog box that I have checked the Smart Radius option, given it an 80 pixel Radius. Then adjusted the Feather to .5 pixels, and Shifted my edge to the plus side by 30%. If you compare the mask edge in this image with the edge in Image 4 you can see how much smoother the transition has become. From here I would typically use the Blur Tool to further refine and smooth my edge transition. Then I save that file separately should I decided to make further refinements in the future. Now I flatten my image and make all of my color, contrast, and exposure adjustments to a final master copy of the photo.

To learn more about the techniques involved in creating HDR images, Jay Goodrich will be teaching a 3 hour workshop at this year’s Summit in McAllen titled HDR as a Photographic Reality. To find more great tips from Jay, visit his blog: http://jaygoodrich-blog.com/.