Though some may object on ostensibly puritanical grounds, the ability to remove extraneous items from an image—e.g., leaves, sticks, bird feeders, etc.—is one of the great advantages of using a powerful tool such as Photoshop to postprocess your images.  The example below speaks for itself.


In this example, the green leaves in the background have been painstakingly removed from the bottom image, resulting in a more striking depiction of the bird.  Indeed, this technique has the potential to so transform the image that the bird ends up appearing as if it was photographed in an entirely different environment from where it was actually seen.
    The primary workhorse of this technique is the Clone tool in Photoshop.  On Apple Macintosh computers, this tool allows you to choose a source location by holding the Option key while clicking the mouse cursor on some part of the current image (or even another image open in a separate window); on Windows computers a similar key combination performs the same function.  Once you’ve indicated the source location via Option-click, you can then begin drawing at another location in the image using the normal click-drag mouse technique that you’ve no doubt become familiar with in your explorations of Photoshop.  Each click-drag operation with the mouse will result in a corresponding region of the source location being cloned (i.e., copied) to the destination location, which is indicated by the current mouse cursor position.  At any time you’re free to re-set the source location via another Option-click, which will then affect all subsequent click-drag operations.
    This technique can obviously be used to effect vast changes to entire regions of an image.  In the above example, portions of the sky in the original image (top pane of the figure) were cloned into the bottom of the image so as to eradicate all evidence of leaves (bottom pane of the figure).  This particular example required about forty minutes of intense mouse work to fully remove all of the leaves from the image.  For the larger regions I used a large-radius clone brush to rapidly erase vast stretches of leafy background from the image.  After this was accomplished, a smaller clone brush was used to carefully attend to the margins of these leafy regions bordered by foreground elements such as sticks, legs, and toes.  The figure below gives another example in which a suet feeder was erased from the image by cloning background pixels over it.

    When choosing a brush for cloning, there are a number of important considerations to keep in mind.  First is obviously the brush size.  For large areas, a large brush is obviously recommended, for the sake of time.  For careful work around the margins of the subject, a smaller brush is advisable, as mentioned above.  In both cases (large-scale and fine-grained) you’ll want to consider the hardness of the brush carefully.  Initial work at large scales can typically use a hard-edged brush, while closer, more detailed work often requires a soft-edge brush for blending with foreground edges.  The earlier example in Fig. 11.5.1 provides one counter-example to the latter suggestion: when brushing around the lower branches a hard-edge brush was used so as to create a harder edge to the branches, making them appear more immediate or up-front. 
    Cloning in Photoshop is an entire art form of its own.  A variety of techniques can be called for in creating smooth transitions around the edges of the cloned region.  The use of soft-edged brushes is an obvious technique.  I like to use a large, hard-edged brush to do the main work, and then to clean up the edges using a smaller, soft-edge brush, possibly with reduced opacity; this also works fairly well for removing halos and shadows and the like.  You can also use the Blur tool to smooth transitions after you’ve cloned in a region from elsewhere.  Be sure to view all of your cloning work with a critical eye afterward, since it’s easy during cloning to fail to notice obvious artifacts, such as textural anomalies that are repeated close to each other.  A combination of edge softness and tasteful opacity can help to remove many anomalies, but don’t underestimate the effort that may be required if you want a truly flawless result.  For images that you’ll only be posting on the internet, a flawless result may not be terribly essential; for large prints on expensive media (such as canvas), you’ll want to be more exacting so as to reduce expensive re-printing costs later after you discover the artifacts in print.
    When cloning in Photoshop, I highly recommend using a new, blank layer as the destination for the cloned pixels, rather than cloning directly onto the existing image layer.  Creating a new, blank layer is a simple as clicking the appropriate icon in the Layers palette.  You may need to activate an option in the clone tool to allow it to clone from all layers, or from merged layers.  Because the cloned pixels will be written to the new layer, rather than destructively overwriting the pixels of the existing image layer, you’ll be able to more easily modify the results of your cloning operation later if necessary.  A common example is when cloning close to the edge of the bird: if you accidentally over-write some of the pixels making up the bird, you can later fix the mistake very simply by engaging the Eraser tool, and then simply erasing the few pixels of the new layer that occlude the bird.  Because you haven’t modified the pixels of the underlying image layer, the original pixels are still available and can be made visible either by erasing pixels from the clone layer or by creating a layer mask and then masking out the offending pixels via the mask (see Chapter 13 for instructions on using layer masks).


    A feature of the clone tool that bears mentioning is the Aligned check-box.  Normally, you’ll want this box to be checked.  Recall that before cloning any pixels to the new location you had to Option-click to indicate the source location from which the pixels would be copied.  You then performed a click-drag to copy a series of pixels to the destination region.  Each subsequent click-drag faithfully copied pixels relative to the original source location.  That is, if you moved your mouse 50 pixels to the right before performing the next click-drag, the source pixels would be correspondingly taken from a location 50 pixels to the right of the previous source location.  If you were to instead uncheck the Aligned box in the clone tool’s parameter bar, then for each successive click-drag, the source location for the cloned pixels would revert each time to the original point where you had Option-clicked.  This latter behavior can be useful if you want to clone the same texture to a multitude of locations.  Most of the time, however, you’ll want to keep the Aligned box checked.
    Note that the Clone tool isn’t the only way to clone image elements.  You can also select a region with your favorite selection tool (see section 10.6), copy that region to a new layer via Cmd-J / Ctrl-J, and then drag that region to a new location via the Move tool.  We used this technique in section 11.2 to copy textures into areas of an image that suffered from clipped highlights.  One advantage of this alternate technique is that you can also rotate the cloned layer and adjust its opacity if necessary.
    As already mentioned, an important issue in cloning is to make sure that you don’t introduce obvious artifacts, such as via repeated elements.  After performing extensive cloning, it’s often worthwhile to follow this with a second round of cloning (preferably on a new, blank layer) in which you attend more carefully to the issue of repeated elements.  Whenever you identify a case of blatantly repeated pixel patterns in the cloned region, during the second pass of cloning you can obliterate one copy of the pattern via another cloning operation (from a different source location, possibly with lower opacity and multiple passes of the mouse cursor). 
    Not all uses of the Clone tool need be as dramatic as those exemplified above.  In the figure below we show the use of this tool to remove a shadow around the bird.


In this example, the bird in the top pane shows a shadow, primarily along its direction of forward motion.  The bird was frozen in flight by an extremely short flash duration, but because the ambient light was comparable in brightness to the flash, a ghosting effect occurred.  In the bottom pane we’ve removed most of the shadow via the Clone tool.  In this case, areas of the background were cloned in close to the bird to erase the shadow.  A Clone brush of between 5 and 10 pixels was used, initially with a hard edge to cleanly paint around the bird’s contour, but then with a soft edge to restore a smooth gradient further out. 
    Note that the source and destination of the cloning operations used in the previous example were mere pixels apart, and in some cases even overlapped slightly.  When the source and destination are so close, you’re effectively pushing pixels, or smearing them, in some direction.  Photoshop has a tool which is dedicated to such small-scale smearing applications, called the Smudge tool:


The Smudge tool is what may be referred to as a blunt instrument—it can be useful when making an initial stab at correcting a problem with an image, but will usually require follow-up work using some other tool providing greater precision or subtlety. 
    Note also that the shadow in the above example is somewhat reminiscent of the types of artifacts that sometimes occur when you separate the bird from the background and apply filters such as noise reduction to the background.  A halo or shadow often results, due to edge effects of the filter.  These can sometimes be prevented from occurring by locking the transparent pixels in the layer, and/or by erasing a thin band of pixels around the subject that has been spliced out into another layer.  If you still end up with a halo effect, you can use the above cloning technique to manually paint away the artifact.
    Another type of artifact that you’ll often want to remove in postprocess is dust spots—small, dark circles resulting from dust specks on your imaging sensor (see section 2.8 for instructions on cleaning dust from your imaging sensor).  The Spot-healing brush is extremely handy for this task (you can also remove blemishes using a similar tool in ACR, or using the Clone tool in Photoshop, but the Spot-healing brush in Photoshop is typically the easiest).  Set the brush size to be slightly larger than the dust spots, and simply click once on each spot.  In rare cases the Spot-healing brush will do a poor job of matching the replacement pixels to the surrounding area, and in these cases you can use the Clone tool with a soft-edged brush to clone over the dust spot from an area just a few pixels away.


    It’s easy to miss a few dust spots during post-processing, especially when you’re concentrating on fixing more obvious issues.  Some dust spots are indeed very subtle (such as the one circled in red in the above figure).  One method for finding the more subtle spots is to invoke the Hand tool and then “shake” the image by dragging it back and forth very rapidly with the mouse (you may need to press the F key a few times to get into Full Screen mode).  If you keep your fingers on the H and J keys, you can rapidly switch between the Hand tool and the Spot-healing brush, allowing you to find and fix all of the dust spots in the image in no time flat.
    Other elements that you may wish to remove via cloning are plumage defects (such as missing feathers), parasites (such as bird ticks), and dirt adhering to the bird’s feathers.  As always, keep in mind that once you start using the Clone tool to fix blemishes in the image, you’re no longer working with a photograph, but rather an idealized, artistic rendering of the bird.  Be sure to make plain to your viewers that the image has been subjected to digital manipulation, and is intended to be viewed as art, rather than as photographic documentation of reality.  As long as you do so, there’s absolutely nothing wrong with making these types of digital manipulations in the name of pure aesthetics.