5Spot cloning removes artifacts after flipping the canvas.
To get realistic results, I needed to clone the outer edges of the thermal pool on the right side of the image and then replace the boardwalk with these cloned edges. The problem is that once I cloned the outer edges of the thermal pool, I had to find a way to change the angle so the edges would be mirrored. This meant I had to flip the area that was cloned horizontally so I could connect the full inclusion of the geyser. I chose to clone the right-side edges using the Marquee tool (M) in the Tools menu.
Once you've selected the Marquee tool, make a selection of where you'd like to clone. Try to make the selection larger than the boardwalk. Once you're happy with the selection, feather the selection: Select > Modify > Feather. Feathering eases the transition so there's a smoother gradient between the selected portion and the rest of the image. It makes the changes less obvious. Remember to do editing on a separate layer, then the background layer. Once you've jumped this selection to a new layer and labeled it, you're ready to start replacing the boardwalk.
6Repeating patterns in the foreground of the pool are removed.
Hold the Command button (Mac) or Control button (Windows) and drag the selected layer over the boardwalk. Now that the layer is on top of the boardwalk, flip the layer horizontally. There are a few ways to do this, but the easiest and most flexible way is to go to Edit > Free Transform. This brings up a selection bar with anchors located at the corners and the side. This tool allows you to transform the image by changing its shape and size. To get the image flipped horizontally, grab the right- or left-side anchor in the middle and pull it over, overlapping the opposite middle anchor so that you're left with the selection flipped. At this stage, I fine-tune the anchors so the edges of the thermal pool line up.
7Hue/Saturation matches colors and tonalities.
We've cloned out the boardwalk at this point, but we've mirrored the outer edges of the thermal pool, thus repeating patterns in the image—an obvious sign of a clone edit. The next step is to clone in new patterns and textures to avoid the repeating patterns along the pool's edge. Three primary tools can be used for cloning. Which ones you should choose depends on the properties of the areas that need the cloning. The first is the Healing Brush (J) in the Tools menu. (Make sure All Layers is chosen in the Options bar and that you're working on a blank new layer properly labeled as something to do with the process of healing.)
8 Unnatural elements are removed from the background.
The key to the Healing Brush is to use several clone sources when sampling. The more areas you sample, the better. To sample or clone an area, hold the Option (Mac) or Alt (Windows) key and click on a source point; the size and hardness of the brush depends on what's being cloned. (You can quickly change the size of the brush by clicking on the left and right Bracket keys on the keyboard; the left key makes it go smaller and the right, larger.) For healing to be effective, alignment and angle are important. Another consideration is to avoid areas of high contrast or uneven areas of luminance. Sampling of these areas can cause bleeding and obvious signs of editing. If you must do cloning in these areas, be sure to adjust color and tonality afterward so that the sampled areas match their new surroundings.
Once you're finished with the healing, zoom in to the image at 100% to get a better look at your editing; make sure to pan around the image for smooth transitions between the edits by holding the Space bar down and dragging around the image. Lastly, zoom out and take another look for the consistency of the image between edits. In areas where healing must be done on high-contrast edges, simply follow the edge by repositioning the content so that everything lines up.